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Contraception program effectively manages bison population

The wild bison roaming Catalina Island are a major attraction for the nearly 1 million tourists who visit the Channel Island’s most popular destination every year. But managing the number of bison so that the herd remains healthy and doesn’t endanger the health of the rest of the Island has been a major challenge for wildlife biologists. A new study by the Catalina Island Conservancy scientists, published in the December supplement of the Journal of Zoo and Wildlife Medicine, reports that the Conservancy’s contraception program proved effective in managing the herd’s numbers. Previously, more than two-thirds of the cows delivered calves every year. After receiving the contraceptive, the calving rate dropped to 10.4% in the first year and 3.3% the following year. The Conservancy’s study demonstrated for the first time that this type of contraceptive will work in a wild herd, a finding that can help improve bison management programs throughout the United States. “The success of the Catalina Island Conservancy’s bison contraception program demonstrates the innovative approaches our scientists undertake in fulfilling our commitment to being responsible stewards of the land and the Island’s resources,” said Ann Muscat, Catalina Island Conservancy president and chief executive officer. “By proving the effectiveness of this humane approach to herd management, this research will be a benefit to bison herds throughout the U.S. It also lays the groundwork for further contraceptive studies in other wild species.”

The bison were first brought to the Island in 1924 for a movie. Over the years, they became an iconic symbol of the Island’s culture. But with no natural predators, the herd grew to some 600 animals. The Catalina Island Conservancy, which protects 88% of Catalina Island, had previously conducted studies that found the Island could support only about 150 to 200 bison. To control the herd’s size, the Conservancy had been periodically conducting roundups and shipping bison to the mainland. “Shipping the bison to the mainland was costly, and it raised concerns about the stress on the animals during shipment and the expansion of the herd beyond ecologically sustainable numbers between shipments,” said Julie King, director of conservation and wildlife management and a co-author of the contraception study. “We launched the contraceptive program because it is a humane and cost-effective solution to managing the herd and protecting the Island’s resources.” Beginning in 2009, the Conservancy’s scientists injected the female bison with porcine zona pellucida (PZP), a contraceptive that had been used for fertility control in zoos, wild horses and white tail deer. In addition to substantially reducing the number of new calves, the PZP had no apparent effect on pregnant females or their offspring. The Conservancy’s scientists continue to study PZP to determine if the female bison can regain their fertility after a period of time without the contraceptive.

“The bison contraception program is a good example of trying to reach a balance with cultural, aesthetic or recreational needs and uses and cost-effective natural resource management to maintain the health of the ecosystem,” said John J. Mack, chief conservation and education officer. “Because humans have been living and changing the Island for thousands of years, the Conservancy is always seeking new approaches to ensuring the long-term use and ecological health of Catalina Island.”

Science Daily
January 21, 2014

Original web page at Science Daily

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The prevalence of colds and pneumonia in cows can be controlled

Respiratory diseases in cattle are a great threat to animal welfare and lead to financial losses in the cattle industry. The bovine respiratory syncytial virus (BRSV) is one of the main causes of respiratory disease in cattle. A study of the prevalence and infection distribution of the virus shows that it is possible to control the virus, even though it occurs very frequently. The BRS virus is equivalent to the human RS virus and causes most of the cases of serious pneumonia that lead to fatalities in calves and to epidemics which can spread to a large number of farms in the same area. The study focused on the prevalence and infection distribution of the virus between Norwegian cattle herds and found that during the course of one year, nearly half of the cattle herds were newly infected, while almost as many herds became free of infection. It therefore appears that the virus does not survive for a long time in one herd and that it should be possible to reduce the number of infections by preventing the herds becoming re-infected. The infection dynamics of the BRSV virus was studied in 134 randomly selected Norwegian dairy herds. Five calves in the herds were tested for antibodies against this virus and then again six months later. A herd was defined as positive if at least one animal aged between 150-365 days was shown to have antibodies against the virus. The young age of the animals tested would indicate that they probably were infected quite recently, i.e. during the course of the last year.

During the study period, a large proportion — 54% — of the herds was shown to be BRSV-positive. The prevalence of the virus varied a great deal in different parts of the country. Several herds with negative test results were located in close proximity to herds infected by the virus and some of the former remained free of the virus, in spite of the presence of several newly infected herds in the neighbouring area. This indicates that it is possible to prevent a herd becoming infected, even in areas with a high prevalence of the virus. 42% of the herds that showed negative results on the first test, showed positive results during the following six months. The frequency of new infections was the same, irrespective of the season. 33% of the herds which had originally tested positive managed to get rid of the infection after six months. The findings of this study indicate that monitoring the prevalence of the virus in order to identify negative herds and focusing on measures to combat infection in these herds ought to be effective strategies for limiting the prevalence and the consequences of BRSV infection in cattle. Knowledge about the most effective methods of preventing herds from becoming infected is still lacking. The research group “Viral infections in cattle” at the Norwegian School of Veterinary Science, which carried out this study, is currently engaged in projects that seek to identify the most effective ways of preventing new infections in herds.

Science Daily
November 26, 2013

Original web page at Science Daily

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Foot and mouth disease in sub-Saharan Africa moves over short distances, wild buffalo

New research shows that in sub-Saharan Africa the virus responsible for foot and mouth disease (FMD) moves over relatively short distances and the African buffalo are important natural reservoirs for the infection. The study, published in mBio®, the online open-access journal of the American Society for Microbiology, sheds light on how the type of FMD virus called SAT 2 emerged in sub-Saharan Africa and identifies patterns of spread in countries where SAT 2 is endemic. “The data suggest that the common ancestor of all SAT 2 was in African buffalo. It’s very clear that historically infections have moved from buffalo to cattle,” says corresponding author Matthew Hall of the University of Edinburgh in Scotland. Foot and mouth disease (FMD) is devastating to livestock all over the world, but it’s a particular problem in Africa, where wildlife that harbor the virus are thought to pass it on to their domesticated cousins. FMD strikes cloven-hoofed animals, presenting as a high fever, blistering in the mouth and feet, decline in milk production in females, and weight loss. Although most animals recover over the course of months, some die of complications from the disease. In wild buffalo, the disease is very rarely symptomatic and animals can be persistently infected for a period of several years. The SAT 2 serotype of the virus is endemic in sub-Saharan Africa, but it has crossed the Sahara and caused outbreaks in North Africa and the Middle East between 1990 and 2012.

In the hopes they could eventually predict future outbreaks, Hall and his colleagues wanted a better picture of the diversity of SAT 2 viruses in sub-Saharan Africa and how they move around from one location to another. They used 250 genetic sequences of the VP1 section of the genome from SAT 2 isolates taken from all over sub-Saharan Africa and tracked the appearance of the various unique ‘topotypes’ over the region. Hall says the patterns in which the topotypes appear in different places gives strong support to the idea that the virus is spread by infected hosts in land movements over relatively short distances. What’s more, African buffalo are an important “maintenance host”, meaning they maintain a reservoir of the virus that can re-infect domesticated animals after time and culling has ended an outbreak among livestock. The relationships between the 250 sequences also indicate that it’s possible the original source of the SAT 2 viruses that are now found in wild and domesticated animals was African buffalo. To Hall, these results indicate that genetic tracking of viruses has a lot of potential for making inferences about viral spread and heading off future outbreaks. “We showed that we can demonstrate virus movement using genetic data. It’s a tool that can be used for that kind of inference. In cases where less is known, this is a valid way of going about answering the questions,” says Hall. Going forward, Hall says he plans to apply a similar approach to studying serotype O FMD viruses in Africa, Asia, and South America to identify links between different animal populations. “It’s good to know the reason it spreads,” says Hall. “It could be quite a contribution to eradication or control efforts.”

EurekAlert! Medicine
November 12, 2013

Original web page at EurekAlert! Medicine

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Hormone disruptors rise from the dead

The vast amounts of steroids that are fed to cattle in some countries end up in farm run-off and may affect the environment even after they are broken down by sunlight. Hormone-disrupting chemicals may be far more prevalent in lakes and rivers than previously thought. Environmental scientists have discovered that although these compounds are often broken down by sunlight, they can regenerate at night, returning to life like zombies. “The assumption is that if it’s gone, we don’t have to worry about it,” says environmental engineer Edward Kolodziej of the University of Nevada in Reno, joint leader of the study. “But we’re under-predicting their environmental persistence.” “Risk assessments have been built on the basis that light exposure is enough to break down these products,” adds Laura Vandenberg, an endocrinologist at the University of Massachusetts in Amherst who was not involved in the study. “This work undermines that idea completely.” Endocrine disruptors — pollutants that unbalance hormone systems — are known to harm fish, and there is growing evidence linking them to health problems in humans, including infertility and various cancers. But pinpointing specific culprits from the vast array of trace chemicals in the environment has proved difficult. Indeed, concentrations of known endocrine disruptors in rivers often seem to be too low to explain harmful effects in aquatic wildlife, says Kolodziej.

He and his colleague David Cwiertny, an environmental engineer at the University of Iowa in Iowa City, decided to find out whether the breakdown products of endocrine disruptors could be boosting their environmental impact. Their team focused on trenbolone acetate, a synthetic anabolic steroid used as a growth promoter in more than 20 million cattle in the United States each year (this practice is banned in the European Union). Cattle metabolize the steroid into compounds such as 17α-trenbolone, a potent endocrine disrupter commonly found in agricultural run-off water. In laboratory tests, just a few tens of nanograms of these compounds per litre can skew sex ratios and decrease fertility in fish. Some manufacturers have argued that these metabolites pose little risk in rivers, however, because sunlight breaks them down rapidly. Kolodziej and his team put solutions of 17α-trenbolone and related compounds through several cycles of light and dark in the laboratory. Although concentrations fell during the simulated daytime, the scientists were surprised to see that levels rebounded during the dark periods. At neutral pH and 25 ºC, it took about five days to regenerate 60% of a sample of 17α-trenbolone from its breakdown products. Higher temperatures or slightly acidic or alkaline conditions accelerated this process.

“I’ve never seen anything like it,” says Vandenberg. Field biologists usually collect water samples during the day, she says, and nocturnal regeneration “would certainly have the potential to impact those results.” Moreover, field studies have rarely reported the pH and temperature of water samples, which could have a big effect on true concentrations of contaminants. “I don’t think that anyone had conceived it could be so important,” she says. The team found the same regeneration process occurring in water samples taken from the Iowa River, and from a test pond seeded with manure from cattle that had been treated with trenbolone acetate. They also note that other steroids with similar chemical structures can regenerate in the same way, including dienogest, an oral contraceptive, and dienedione, an illicit anabolic steroid. The results are published in Science. Kolodziej says that the work casts considerable uncertainty over sampling results for steroid endocrine disruptors, and suggests that a survey of their breakdown compounds in the environment is now urgently needed. It also highlights a serious drawback in relying on studies that look for single environmental contaminants, rather than a spectrum of their derivatives, he adds. Chemical studies should be complemented with bioassays that use living cells to detect endocrine disruptors, Vandenberg adds. Last year, a bioassay of this kind found androgens in 35% of freshwater samples tested, far more than chemical assays would suggest. “What you really want to know is if there’s anything in there that can cause biological activity,” says molecular biologist Gordon Hager, at the National Cancer Institute in Bethesda, Maryland, who developed the assay. Yet current environmental monitoring procedures still rely on checking “a list of chemicals, and they only know how to look for one thing at a time”, he says. “It’s a fool’s errand.”

Nature
October 15, 2013

Original web page at Nature

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African breed of cattle harbors potential defense against life-threatening parasite

Every year, millions of cattle die of trypanosomosis. The UN and the International Livestock Research Institute list trypanosomosis among the ten diseases of cattle with the greatest impact on the poor. In Africa the disease is known as “Nagana,” which translates literally as “being in low or depressed spirits.” The disease is caused by a parasite that enters the animals’ blood as a result of the bite of the Tsetse fly. Surprisingly, one West-African dwarf cattle breed, the Baoulé, seems less affected by trypanosomosis than others. When they are infected, Baoulé cattle develop fever and lose weight but do not necessarily die. Their immune system is thus better able to fight the parasite than that of other breeds. In other words, the cattle seem to have a natural tolerance against the parasite. Katja Silbermayr from the Institute of Parasitology of the University of Veterinary Medicine, Vienna (Vetmeduni), together with an international research team, collected blood samples from three cattle types. The scientists have developed a method that can identify the parasites responsible for trypanosomosis, the trypanosomes, and can even detect three different forms of the parasite in a single step. The information is extremely valuable to veterinarians and farmers as each type of trypanosome causes a slightly different disease progression and requires a different type of treatment.

The researchers used their new method to examine samples of blood from apparently healthy Baoulé cattle, Indian Zebu cattle and crosses between the two breeds. Zebus produce more meat and milk than Baoulé but fall severely ill when infected with trypanosomes. Of over 350 animals tested, 41 were found to be infected. Zebus were infected twice as often as Baoulés or hybrid cattle. Nevertheless, the highest amounts of the parasite were found in some Baoulés. “Baoulés are infected less often than Zebus and seem able to tolerate higher amounts of the parasite. We only studied healthy animals and Zebus with such high parasite levels would have been too ill to be included in our study,” says Silbermayr. It seems that the Baoulé’s immune system can tolerate higher levels of the blood parasite. A number of international research projects are attempting to breed trypanosome-tolerant cattle and international aid agencies are providing funding to preserve the indigenous African breed. “The genetic background of the Baoulé is very valuable for African agriculture. Crossing large breeds of cattle that produce a lot of meat and milk, such as the Zebu, with the smaller but immunologically stronger Baoulé could be very beneficial for farming in Africa. We plan to examine the current extent of mixing between Baoulés and Zebus and hope that in future it will be possible to determine the optimal degree of mixing to offer protection against trypanosomes,” explains Silbermayr.

Science Daily
October 15, 2013

Original web page at Science Daily

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Vaccinating cattle against the E. coli O157 bacterium could cut the number of human cases of the disease by 85%, according to scientists

The bacteria, which cause severe gastrointestinal illness and even death in humans, are spread by consuming contaminated food and water, or by contact with livestock feces in the environment. Cattle are the main reservoir for the bacterium. The vaccines that are available for cattle are rarely used, but could be significant. The research was lead by a team of researchers at the University of Glasgow in collaboration with the University of Edinburgh, the Royal Veterinary College, Scotland’s Rural College, Health Protection Scotland, and the Scottish E. coli O157/VTEC Reference Laboratory. The study, published in the online journal PNAS, used veterinary, human and molecular data to examine the risks of E. coli O157 transmission from cattle to humans, and to estimate the impact of vaccinating cattle. The risk of E. coli O157 infection is particularly significant when the cattle are ‘super-shedding’ — excreting extremely high numbers of bacteria in their feces for a limited period of time. Vaccines against the bacteria exist that can reduce super-shedding. As a consequence, the researchers predict that vaccinating cattle could reduce human cases by nearly 85 percent, far higher than the 50 percent predicted by studies simply looking at the efficacy of current vaccines in cattle.

These figures provide strong support for the adoption of vaccines by the livestock industry, and work is now underway to establish the economic basis for such a program of vaccination. In addition, research is continuing in Scotland by the same collaborative grouping to develop even more effective vaccines that would further reduce the impact on human disease. Lead author, Dr Louise Matthews, Senior Research Fellow in the Institute of Biodiversity, Animal Health and Comparative Medicine, said: “E. coli O157 is a serious gastrointestinal illness. The economic impact is also serious — for instance studies in the US suggest that healthcare, lost productivity and food product recalls due to E. coli O157 can cost hundreds of millions of dollars each year. “Treating cattle in order to reduce the number of human cases certainly makes sense from a human health perspective and, while more work is needed to calculate the cost of a vaccination program, the public health justification must be taken seriously.” In Scotland, an average of 235 culture positive cases of E. coli O157 infection per year (i.e. people who had the organism in their stools) were notified to Health Protection Scotland from 2008 to 2012. The vaccines that are available currently have poor take-up: one version in the US is not fully licensed because medicines for veterinary use must show that animal health is improved. This is problematic because E. coli O157 does not harm cattle and assessing the impact of treatment involves coordination between human and veterinary health practitioners.

Science Daily
October 1, 2013

Original web page at Science Daily

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Divergent astrovirus associated with neurologic disease in cattle

Using viral metagenomics of brain tissue from a young adult crossbreed steer with acute onset of neurologic disease, we sequenced the complete genome of a novel astrovirus (BoAstV-NeuroS1) that was phylogenetically related to an ovine astrovirus. In a retrospective analysis of 32 cases of bovine encephalitides of unknown etiology, 3 other infected animals were detected by using PCR and in situ hybridization for viral RNA. Viral RNA was restricted to the nervous system and detected in the cytoplasm of affected neurons within the spinal cord, brainstem, and cerebellum. Microscopically, the lesions were of widespread neuronal necrosis, microgliosis, and perivascular cuffing preferentially distributed in gray matter and most severe in the cerebellum and brainstem, with increasing intensity caudally down the spinal cord. These results suggest that infection with BoAstV-NeuroS1 is a potential cause of neurologic disease in cattle.

Astroviruses are small, nonenveloped, positive single-stranded RNA viruses with a genome of 6.4–7.3 kb. The family Astroviridae comprises 2 genera, Mamastrovirus and Avastrovirus, known to infect mammals and birds, respectively. Since the first description of human astrovirus (HAstV) in children with diarrhea in 1975, a wide variety of astroviruses have been reported in multiple animals including humans, cattle, pigs, sheep, minks, dogs, cats, mice, sea lions, whales, chickens, and turkeys. Enteric astroviruses are transmitted through the fecal–oral route, and regardless of species, most infections are asymptomatic. In humans, the prevalence of exposure is very high, and astrovirus infection is a major cause of acute enteritis in infants. Clinical disease also can affect elderly and immunocompromised persons. In these persons, the clinical course of infection is acute, with 2–4 days of watery diarrhea and, less commonly, vomiting, headache, fever, abdominal pains, and anorexia. Astroviruses have been implicated twice in central nervous system (CNS) disease. One study demonstrated an HAstV-PS, which is distinct from the original HAstV and closely related to astrovirus HMO-C (AstV-HMO-C) and HAstV-VA1 in the brain tissue of a 15-year-old boy with X-linked agammaglobulinemia who had encephalitis. HAstV-PS was the only virus detected, and astrocyte infection was confirmed by anticapsid antibody staining. Serologic evidence of exposure to the closely related AstV-HMO-C was found in 36% of 5–10-year-old children in the United States, which reflects a common childhood infection and indicates that the encephalitis in this child was a likely consequence of his immunodeficiency. In an outbreak of so-called “neurological shaking disease” in mink, an astrovirus (Mink AstV-SMS) was detected in the brain tissues of multiple naturally and experimentally infected animals showing neurologic signs, including shaking and ataxia.

Cattle with neurologic signs are vigilantly screened to keep the food chain free of zoonotic pathogens, such as rabies virus, Salmonella spp., Listeria monocytogenes, Chlamydia spp., and the prion agent of bovine spongiform encephalopathy (BSE). In particular, BSE has become a major public health concern after recognition of the association between BSE and prion-associated disease in humans. Therefore, early and rapid recognition of the cause of neurologic disease is vital to the safety of the food chain. Etiologic diagnosis of CNS disease in cattle requires substantial effort; is costly; and usually presents a challenge because of the large number of pathogens or problems that can cause neurologic disease, including viruses, bacteria, parasites, prions, toxins, and metabolic disorders. Pathogens known to cause CNS disease in cattle include bovine herpesvirus 1 and 5 (BoHV-1 and BoHV-5), lyssavirus (rabies), ovine herpesvirus 2, L. monocytogenes, Histophilus somni, Escherichia coli, Salmonella spp., Chlamydia spp., Neospora caninum, amoebas, and prions. Brain tissue from a yearling steer with an encephalomyelitis and ganglioneuritis of unknown origin was analyzed by using viral metagenomics, which showed a divergent astrovirus distantly related to an ovine astrovirus. By retrospective analysis, this bovine astrovirus associated with neurologic symptoms (BoAstV-NeuroS1) was detected in the brains of 3 of 32 other cattle with encephalitides of undetermined etiology. Virus was detected by RNA by in situ hybridization within neurons in the brainstem, cerebellum, and/or spinal cord in all PCR positive samples from the 4 animals in this study.

Emerging Infectious Diseases
September 17, 2013

Original web page at Emerging Infectious Diseases

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Antibiotic-resistant strains of Salmonella tracked from farm to fork

Continuing research on Salmonella may enable researchers to identify and track strains of antibiotic resistant bacteria as they evolve and spread, according to researchers in Penn State’s College of Agricultural Sciences. Tracing the transmission of individual strains from agricultural environments to humans through the food system is difficult because of the rapid evolution of resistance patterns in these bacteria. Resistance patterns change so quickly that, until now, it has been impossible to determine where some highly resistant strains are coming from. Michael DiMarzio, a doctoral candidate in food science working under the direction of Edward Dudley, associate professor and Casida Development Professor of Food Science, developed a method for identifying and tracking strains of Salmonella enterica serological variant Typhimurium as they evolve and spread. Every year in the United States, the various strains of Salmonella together are responsible for an estimated 1 million illnesses, 20,000 hospitalizations and 400 deaths at an economic cost exceeding $3 billion. Salmonella Typhimurium accounts for at least 15 percent of clinically reported salmonellosis infections in humans nationally. The number of antibiotic-resistant isolates identified in humans is increasing steadily, suggesting that the spread of antibiotic-resistant strains is a major threat to public health.

Typhimurium infections have exhibited a gradual decline in susceptibility to traditional antibiotics, a trend that is concerning in light of this pathogen’s broad host range and its potential to spread antibiotic resistance determinants to other bacteria,” DiMarzio said. “Now more than ever, it is imperative to effectively monitor the transmission of Salmonella Typhimurium throughout the food system to implement effective control measures.” Building on recent research done in Dudley’s lab, DiMarzio developed the new approach to identify antibiotic resistant strains of Salmonella Typhimurium focusing on virulence genes and novel regions of the bacteria’s DNA known as clustered regularly interspaced short palindromic repeats, or CRISPRs. They report their results in the September issue of Antimicrobial Agents and Chemotherapy. CRISPRs are present in many foodborne pathogens. The researchers demonstrated that CRISPR sequences can be used to identify populations of Salmonella with common antibiotic-resistance patterns in both animals and humans. “Specifically, we were able to use CRISPRs to separate isolates by their propensity for resistance to seven common veterinary and human clinical antibiotics,” DiMarzio said. “Our research demonstrates that CRISPRs are a novel tool for tracing the transmission of antibiotic-resistant Salmonella Typhimurium from farm to fork.” DiMarzio found that several subtypes of Salmonella Typhimurium showed up repeatedly in the frozen collection of Salmonella samples taken from cows, pigs and chickens in Penn State’s Animal Diagnostic Laboratory. In this case, researchers looked at 84 unique Salmonella Typhimurium isolates collected from 2008 to 2011.

“We know those strains are widely disbursed, and the thing they have in common is that they have noticeably higher levels of antibiotic resistance,” he said. “So we examined clinical samples of Salmonella taken from humans, and it turned out that we see an overlap — the ones we see in humans are the ones we see a lot in animals. You would expect that, but it is confirmation that our method works.” DiMarzio noted that the researchers identified subsets of the overall Salmonella bacteria population that seem to be more prone to acquiring antibiotic resistance. “Our challenge now is to learn what makes those strains different — why do some strains acquire resistance while others don’t, even though both are circulating widely among animal populations?” he said. “We will need to know that to try to control them.”

Science Daily
September 17, 2013

Original web page at Science Daily

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Whole genome sequencing provides researchers with a better understanding of bovine TB outbreaks

The use of whole bacterial genome sequencing will allow scientists to inexpensively track how bovine tuberculosis (TB) is transmitted from farm to farm, according to research presented this week at the Society of General Microbiology Autumn Conference. Bovine TB is primarily a disease of cattle, caused by the bacterium Mycobacterium bovis. The disease is hugely expensive, costing the Government over £91 million in England in 2010/11. Researchers from the University of Glasgow, working in collaboration with the Agri-Food and Biosciences Institute and the Department of Agriculture and Rural Development, Northern Ireland, sequenced the genomes of 147 M. bovis samples, collected over a decade of outbreaks in Northern Ireland. By combining the genomic sequences of the bacteria with information about when and where the sample was isolated, in addition to data on the movement of cattle from farm to farm, the researchers were able to build a detailed forensic map of bovine TB spread. The results showed that, even on a scale of few kilometres, M. bovis samples from neighbouring farms were more closely genetically related than geographically distant farms that had had cattle moved between them. This finding confirms that, while long distance spread via cattle movements plays a role, local transmission mechanisms appear to drive the spread of the disease, although the researchers are unable to determine what these are at the present time.

Hannah Trewby, who is presenting this work says, “The inclusion of whole genome information in our data will give us unprecedented insight into how bovine TB spreads, and will help us to develop better control methods for the disease.” The role of infected wild badgers in spreading bovine TB remains controversial. This work will help to clarify the role that badgers may have in spreading the disease and continue to build a sound scientific evidence base on which control measures can be built. Professor Rowland Kao, the Principle Investigator of the project, explains, “Our results suggests that the establishment and local persistence of the pathogen in cattle has a distinct spatial signature — we believe that explaining this signature is the key to quantifying the role that badgers play in the persistence of bovine TB in Britain and Ireland. While we do not yet have sufficient data to be definitive, it is clear that whole genome sequencing of the bacterium will play an important part in solving this puzzle. Given the extensive collection of samples already collected from cattle and badgers, we are optimistic that this approach will help accumulating the right scientific evidence over the coming years to tackle this important problem.”

Science Daily
September 17, 2013

Original web page at Science Daily

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MRSA strain in humans originally came from cattle

A strain of bacteria that causes skin and soft tissue infections in humans originally came from cattle, according to a study to be published in mBio®, the online open-access journal of the American Society for Microbiology. The researchers who conducted the genetic analysis of strains of Staphylococcus aureus known as CC97 say these strains developed resistance to methicillin after they crossed over into humans around forty years ago. Today, methicillin-resistant S. aureus (MRSA) strain CC97 is an emerging human pathogen in Europe, North and South America, Africa, and Asia. The findings highlight the potential for cows to serve as a reservoir for bacteria with the capacity for pandemic spread in humans. The researchers sequenced the genomes of 43 different CC97 isolates from humans, cattle, and other animals, and plotted their genetic relationships in a phylogenetic tree. Corresponding author Ross Fitzgerald of the Roslin Institute and the University of Edinburgh in Scotland says strains of CC97 found in cows appear to be the ancestors of CC97 strains from humans. “Bovine strains seemed to occupy deeper parts of the phylogenetic tree — they were closer to the root than the human strains. This led us to conclude that the strains infecting humans originated in cows and that they had evolved from bovine to human host jumps,” says Fitzgerald.

Although the CC97 strains from animals were quite genetically diverse, the human isolates cluster together in two tight, distinct “clades,” or relatedness groups, indicating that S. aureus CC97 in cattle crossed over into humans on two separate occasions. Using mutation rates as a molecular clock, the authors determined that the ancestor of clade A jumped from a bovine host to humans between 1894 and 1977 and clade B made the jump between 1938 and 1966. After they made the jump, the human CC97 strains acquired some new capabilities, says Fitzgerald, thanks to genes encoded on portable pieces of DNA called mobile genetic elements. “It seems like these elements, such as pathogenicity islands, phages, and plasmids, are important in order for the bacterium to adapt to different host species,” says Fitzgerald. “The reverse is true as well: the bovine strains have their own mobile genetic elements.” Perhaps the most problematic new capability the human strains acquired is the ability to resist methicillin, an important antibiotic for fighting staphylococcal infections. Only human strains of CC97 were able to resist the drug, which indicates that the bacteria acquired resistance after they crossed over into humans, presumably through exposure to antibiotics prescribed for treating human infections.

This sequence of events contrasts with the case of a S. aureus strain from pigs, Fitzgerald points out, since a study in 2012 revealed that MRSA ST398 strains evolved the ability to resist methicillin before they crossed over into humans. Any number of factors could create these differences, making pigs — but not cattle — a source of a drug-resistant bacterium. At this point, though, there isn’t enough information to say whether differences in the S. aureus strains, differences between pigs and cattle, or differences between swine and dairy farming practices might be responsible. Moving forward, Fitzgerald says he and his colleagues plan to widen the investigation. “We have a relatively small sample size, and the findings are robust, but we want to extend the study now to include a greater number of clones to get a bigger picture of what’s going on across the S. aureus species,” says Fitzgerald. A wider variety of S. aureus strains, Fitzgerald says, from a wider variety of locations and hosts and a wider range of time, will allow them to better pinpoint the timing and circumstances of the host jump events. Understanding how and when MRSA has crossed over from other species in the past can help us to put the brakes on these crossovers in the future and hopefully prevent the birth of the next pandemic S. aureus strain.

Science Daily
September 3, 2013

Original web page at Science Daily

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Rinderpest research restarts

Rinderpest has been eradicated, but vigilance and surveillance are needed to ensure it doesn’t come back. Research is set to resume on the rinderpest virus, the cause of a deadly cattle disease that was declared eradicated in 2011 and has been off limits for study ever since. The moratorium — part of efforts to guard against accidental or intentional release of virus that could reintroduce the disease — was lifted on 10 July and replaced by a new international oversight system for such research. In its heyday, the disease — the only one other than smallpox to be eradicated from nature — killed hundreds of millions of cattle, mainly in Europe, Asia and Africa, often leaving famine in its wake. Under the new oversight system, run by the Food and Agriculture Organization of the United Nations (FAO) in Rome and the Paris-based World Organisation for Animal Health (OIE), the risks and benefits of research proposals will be assessed by a joint advisory committee, and then the FAO and the OIE will decide on approvals. Eligible research must show potential for substantial practical or scientific benefits and be conducted under stringent biosafety and biosecurity conditions. The first project that has garnered approval will test whether vaccines developed against a closely related virus — peste des petits ruminants (PPR), which causes disease in sheep and goats — might also protect cattle against rinderpest. Led by Michael Baron, a rinderpest researcher at the Institute for Animal Health in Pirbright, UK, the project, if successful, would eliminate the need to retain stocks of live-attenuated rinderpest vaccine. That would contribute to the goal of reducing the number of labs worldwide holding rinderpest material, thus decreasing the risk of reintroduction.

Some 55 labs in 35 countries still hold some kind of rinderpest virus, according to a 2011 survey published in January 2012 in the journal Emerging Infectious Diseases: 37% of them in Asia, 29% in Africa and 26% in Europe (G. Fournié et al. Emerging Infect. Dis. http://doi.org/m7w; 2013). The identities of the labs remain confidential. The most dangerous stocks are of live field strains of virus, estimated to be kept in at least 16 labs in 14 countries, and samples of blood and tissues from infected herds, kept in at least 10 labs in 10 countries. Stocks of live-attenuated vaccine, currently held in at least 53 labs in 34 countries, are deemed less problematic, although some could, in theory, revert to disease-causing forms. The FAO and the OIE hope to eventually reduce the number of sites holding live wild viruses to a handful of officially designated labs, ideally located outside regions where accidental releases could have devastating consequences, says David Ulaeto, a virologist and member of the joint advisory committee. Conversely, the agencies plan to centralize stocks of vaccines in a few high-containment repositories in regions at highest risk of disease, so that they can be deployed within hours of any confirmed recurrence of rinderpest. No siting decisions have been made, but one might imagine a repository in Africa, one or two in Asia and one in Europe, says Juan Lubroth, the FAO’s chief veterinary officer. The process of destroying virus or shipping it to centres with high biosafety levels must be done in a way that does not risk its release, says Ulaeto. The FAO and the OIE are working on high-security protocols for shipping the virus and ways to ensure that autoclaves in labs holding it are certified to function at levels guaranteed to provide a 100% kill. Many countries are reluctant to give up their vaccine stocks in case the disease should reappear and threaten their food supply. They worry about becoming dependent on the willingness of the international community to swiftly provide them with needed vaccines. “The challenge is political,” says Bernard Vallat, director general of the OIE. He says that the FAO and the OIE are drafting agreements and international contingency plans that should help reassure countries that swift help would be forthcoming and that they would have guaranteed access to vaccine from FAO–OIE repositories. Vallat notes that if Baron proves that PPR vaccines can protect cattle against rinderpest, it would provide an elegant way around such political issues: there would no longer be any need to hold onto rinderpest vaccines. Baron says that he hopes to start the vaccine-challenge trials next spring and complete them by the end of 2014.

Nature
August 6, 2013

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Survey shows increase in resistance to drug therapies among bovine respiratory disease cases

A survey of records of bovine respiratory disease cases at the Kansas State Veterinary Diagnostic Laboratory showed that drug resistance in one of the primary pathogens that cause BRD, Mannheimia haemolytica, increased over a three-year period. “We have been seeing an increase in the number of antibiotic resistant bacteria that cause pneumonia (also called BRD) in cattle,” said Brian Lubbers, assistant professor in the diagnostic lab, based at Kansas State University. “Many of these bacteria are resistant to, not one, but almost all of the antibiotics that we use to treat pneumonia in cattle.” BRD is one of the most important diseases of feedlot cattle, particularly, said Lubbers, adding that the economic toll from the disease has been estimated to approach $1 billion annually in the United States alone, if one takes into account drug and labor costs, decreased production, and animal death losses. Until now, one of the aspects that has not been studied very well is the cost linked to antimicrobial resistance in BRD cases, he said. To take a closer look, he and colleague Gregg Hanzlicek, also an assistant professor in the diagnostic lab, examined records of cases in which specimens of bovine lung tissue were submitted to the diagnostic lab over the three years, 2009 to 2011. Most of the cattle were from Kansas and Nebraska. They found that over that period, a high percentage of M. haemolytica bacteria recovered from cattle lungs were resistant to several of the drugs typically used to treat that pathogen. The researchers also found, however, that no specimens were resistant to all six antimicrobial drugs. The study was funded internally by the diagnostic lab.

Using resistance to three or more antimicrobials as the definition of multi-drug resistance, 63 percent of the bacteria would be classified as multidrug resistant in 2011, compared with 46 percent in 2010 and 42 percent in 2009. The results of the study were published by the Journal of Veterinary Diagnostic Investigation. “Antimicrobial resistance in veterinary medicine has received a considerable amount of recognition as a potential factor leading to antimicrobial resistance in human medicine,” Lubbers said. “However, the contribution of multidrug resistance to limited or failed therapy in veterinary patients has received much less attention.” Because there are a limited number of antimicrobial drugs that can be used for treatment of BRD pathogens, Lubbers said, multidrug resistance in those pathogens poses a severe threat to the livestock industry. “We (KSVDL) consider this type of information to be part of our active ongoing disease surveillance and will continue this work,” Lubbers said. “The questions of how these bacteria develop or where they come from, how widespread they are, and what is the impact on cattle production are still unanswered. We are actively seeking industry partners to investigate these questions.”

Science Daily
July 23, 2013

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Unusual antibodies in cows suggest new ways to make medicines for people

Humans have been raising cows for their meat, hides and milk for millennia. Now it appears that the cow immune system also has something to offer. A new study led by scientists from The Scripps Research Institute (TSRI) focusing on an extraordinary family of cow antibodies points to new ways to make human medicines. “These antibodies’ structure and their mechanism for creating diversity haven’t been seen before in other animals’ antibodies,” said Vaughn V. Smider, assistant professor of cell and molecular biology at TSRI and principal investigator for the study, which appeared as the cover story in the June 6, 2013 issue of the journal Cell. Antibodies, part of our immune system, are large proteins that resemble lobsters — with a tail and two identical arms for grabbing specific targets (called “antigens,” often parts of bacteria or viruses). At the business end of each arm is a small set of protein loops called complementarity-determining regions or CDRs, which actually do the grabbing. By rearranging and mutating the genes that code for CDRs, an animal’s immune system can generate a vast and diverse population of antibodies — which collectively can bind to just about any of the body’s foreign invaders.

In humans and in many other mammals, most of an antibody’s specificity for a target is governed by the largest CDR region, CDR H3. Researchers have been finding hints that an unusually long version of this domain can sometimes be the key to a successful defense against a dangerous infection. For example, in a study reported in Nature last August, Ian A. Wilson, who is Hansen Professor of Structural Biology and chair of the Department of Integrative Structural and Computational Biology at TSRI, and collaborators isolated an anti-HIV antibody with a long CDR H3 region — twice normal length — which allows it to grab a crucial structure on the virus and thereby neutralize the infectivity of most HIV strains. Waithaka Mwangi, assistant professor in the Texas A&M College of Veterinary Medicine and Biomedical Sciences (CVM) and an author on the Cell paper, suggests thinking of these long CDRs as a probe on a thin extended scaffold that can fit narrow crevices to reach and bind unique hidden pathogen determinants that ordinary antibodies cannot. Reports on these antibodies recently caught the interest of Smider, whose area of research includes finding new ways to generate therapeutic antibody proteins. “We started thinking about how we could make these long CDR3s that are so rare in humans, and we knew from the literature that cows make even longer ones all the time,” he said.

To investigate, Smider assembled a collaboration that included the TSRI laboratories of Wilson and Peter G. Schultz, who is the Scripps Family Chair Professor of Chemistry, as well as researchers at CVM. Michael F. Criscitiello, assistant professor at the CVM and a co-author of the paper, embraced the chance to contribute to the groundbreaking study and noted researchers at CVM offered key immunology proficiency with — and access to — cows. “Such collaborations bring together specialists in diverse fields and certainly facilitate future research,” added Terje Raudsepp, associate professor at the CVM and another of the study’s authors. The team performed a detailed structural and sequence analysis of these unusually long CDR H3 cow antibodies, to gain insight into how they are made naturally — and how such structures might be engineered in the laboratory. First author Feng Wang, at the time a postdoctoral research associate with Schultz and Smider at TSRI, led the effort to purify long CDR H3 cow antibodies — which represent about 10 percent of the cow antibody repertoire — and analyze their corresponding gene sequences. Co-first author Damien C. Ekiert, at the time a graduate student in the Wilson laboratory at TSRI, was able to crystallize the long CDR H3 antibody samples and determine the 3D atomic structures of two representative antibodies by X-ray crystallography. Although the structure of the long CDR H3 protein in Wilson’s human anti-HIV antibody had seemed unusual, the corresponding structure in the cow antibodies turned out to be unique in the known world of animal antibodies: a long “stalk” element topped by an antigen-binding “knob.” Sequencing of the DNA that codes for the knob region revealed an unusual abundance of cysteine — a sulfur-containing amino acid that is apt to bond to a nearby cysteine on the same protein chain, thus forming a loop.

Analyses of these DNA sequences also indicated that, in the cow B-cells where these antibodies are made, the knob-coding gene segments are extraordinarily likely to develop point mutations that either add or subtract cysteines. The effect of these tiny mutations is to create or remove — often radically — antigen-grabbing loops on the structure. “This is a very efficient way to evolve new protein folds,” said Wang. Indeed, it seems to be the principal way in which the cow immune system creates a diverse set of these long CDR H3 antibodies. In the cows, binding of these antibodies to viruses is almost entirely done by the knob on the long CDR H3, which shows that these antibodies do have an important function in the immune system. “For the very first time we have an ultra-long CDR3 antibody binding to an actual pathogen,” said Mwangi. One question that remains is why the cow immune system evolved to make such antibodies. Smider suspects that it has to do with cows’ unusual, four-chambered, grass-fermenting stomach, with its extensive collection of bacteria and other microorganisms. “If some of these escape from the stomach and get into the bloodstream or other tissues, there could be some pretty serious infections; so that’s our starting hypothesis for why cows have this unusual immune defense,” he said.

The stalk-and-knob structure of the CDR H3 loops on these antibodies, which resemble structures found in some insect poisons and other proteins, also suggest that they evolved to grab a particular type of target. “What comes to mind are ion channel or pore structures in the walls of cells,” Smider said. “In any case, we’re hoping to find out whether any of the structures targeted by these knobs exist on microorganisms that cause human disease.” Smider, Schultz, and Wang, who now has his own laboratory at the California Institute for Biomedical Research (CALIBR), hope to harness the potential power of long CDR H3 antibodies for a wide variety of human — and perhaps also veterinary — medical applications. “One approach we’re taking is to immunize cows with antigens of interest to see if we can recover antibodies that neutralize the antigens using these elongated CDR H3 proteins,” said Wang. Another approach, said Smider, is to generate extensive “libraries” of long CDR H3 antibodies in the laboratory and select for those antibodies that have a desired effect. Fabrus Inc, a company founded by Smider and whose scientists were collaborators on the study, is building these libraries for therapeutic discovery. CALIBR, founded by Schultz to translate scientific findings into medicines, also is investigating the possibility of replacing the knob region of such antibodies with known therapeutic proteins to increase their stability and potency. “It’s somewhat rare in science that you find something so unexpected and then have the opportunity to study it in depth — and then get to develop real biomedical applications from it,” Smider said.

Science Daily
June 25, 2013

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Vets and medical doctors should team up to tackle diseases transmitted from animals to humans

A new study at the Institute of Tropical Medicine (ITM) in Antwerp analyses the impact of animal brucellosis and bovine tuberculosis (BTB) on animals and people in urban, peri-urban and rural Niger. The World Health Organization (WHO) ranks them as major zoonoses, infectious diseases transmitted between species. The research maps risk factors for transmission of these diseases from animals to humans, indicating that closer collaboration between medical doctors and veterinarians is required. Interviews with the local population identified the main risk factors for transmission; consumption of unpasteurised milk, lack of hygiene in households, presence of coughing animals in the herd, and absence of quarantine. “Milk is an important source of protein in Niger. Animals graze in rural areas, but are brought to the city when lactating in order to be as close as possible to the consumer. Mapping these kind of dynamics provides vital information about the diseases and how they are transmitted,” said Abdou Razac Boukary about his doctoral research at ITM and the University of Liège (Ulg). The study concludes that it is crucial to address the interlinks between humans, animals and the environment to control animal brucellosis and BTB. They are both an economic and a public health threat. While contagion is extremely unlikely in industrialised countries, the largest part of the world’s population lives in areas where animal brucellosis and bovine tuberculosis are not under control. Hence, ITM calls for increased collaboration between animal and human health specialists in a so called “One Health” approach.

“We should not forget that more than 60% of human pathogens originate from animals. But raising awareness about these relatively unknown diseases is also crucial from an economic perspective. According to an African saying, if livestock die so does the village,” said ITM scientist Eric Thys, co-promoter of the thesis. Abdou Razac Boukary, an agronomist and advisor to the government of Niger, brought together a group of human and animal health specialists for his PhD research. Boukary studied brucellosis and BTB in over 1100 households keeping livestock. He collected nearly 5000 blood samples for brucellosis and tested almost 400 cattle for BTB. Such a large scale approach involving animal and human health specialists is still a rarity. Results show that around 13% of herds included animals infected with brucellosis. It was found that animals below the age of one were more likely to fall ill than animals aged 1-4 years. Around one in hundred cows were found to be infected with BTB. Analysis of samples taken at the abattoir of Niamey showed that cows were significantly more affected by BTB than other categories of cattle. The research also characterised a new profile of Mycobacterium bovis bacterium (SB1982) which has never been reported before. In humans, brucellosis induces undulating fever, sweating, weakness, anemia, headaches, depression, as well as muscular and bodily pain, testicular inflammations in men and spontaneous abortion in pregnant women. Human tuberculosis from animal origin can affect the lungs but is often located in others part of the body. While contagion is extremely unlikely in industrialised countries, the largest part of the world’s population lives in areas where animal brucellosis and bovine tuberculosis are not under control.

Science Daily
May 14, 2013

Original web page at Science Daily

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Synthetic vaccine could prevent future outbreaks of foot-and-mouth disease

Virologists have devised a way to create an entirely synthetic vaccine for foot-and-mouth disease. The vaccine could prevent future outbreaks of the disease, and potentially lead to new treatments for polio and other human diseases. Bryan Charleston, head of the Livestock Viral Diseases Programme at the Pirbright Institute in Woking, UK, and his colleagues used computer simulations to create a model of the protein shell of the virus that causes the disease, then reconstructed it from synthetic protein components. The synthetic shell contains no genetic material, and so it cannot infect the animals. But it will spur the immune system to produce antibodies that would protect them from the real virus. In 2001, an outbreak of foot-and-mouth disease in the United Kingdom led to the destruction of nearly 10 million animals. It cost the economy an estimated £8.5 billion (US$12.9 billion) in agricultural and tourism costs, and spurred a decision to protect against future outbreaks with vaccination rather than mass slaughter. In 2007, however a vaccine made from inactivated virus caused another UK outbreak. The authors say that there is absolutely no chance that their new vaccine could revert into an infectious virus because it contains no viral genes. Also, being entirely synthetic, it cannot be contaminated with live virus during manufacturing.

It will be 6–8 years before the vaccine is available to farmers, they estimate. But if the method used to create the vaccine proves successful when scaled to commercial production, it could also be used to create vaccines for human diseases that are caused by viruses of the same family, such as hand, foot and mouth disease, which is ubiquitous in Southeast Asia, and polio, which still blights the lives of millions of people in the developing world. “Viruses are all very different from each other, and each will come with its own set of problems to solve,” says co-author David Stuart, a structural biologist at the University of Oxford, UK, who is working with the World Health Organization and the Gates Foundation to apply the techniques to the eradication of polio. ”But if we could use this to move away from inactivated polio viruses in the vaccines, it would have very powerful impacts because we are so close to ending this disease.” Earlier attempts to produce a synthetic vaccine for foot and mouth disease were often thwarted by peculiarities of viral geometry. Both the polio and foot-and-mouth viruses are shaped as an icosahedron — a polyhedron with 20 triangular faces. “When those are clipped together, it’s the edges that are the weak spots,” explains Charleston. The synthetic protein shells simply fall apart during transport and dissemination, rendering the product useless. The team got around the problem by engineering the vaccine to have disulphide bonds cross-linking the protein triangles together. This makes the structure more stable, which means it will not require cold storage and that it will be cheaper to produce and distribute. The results are published in PLoS Pathogens.

Nature
April 16, 2013

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In beef production, cow-calf phase contributes most greenhouse gases

Scientists have long known that cattle produce carbon dioxide and methane throughout their lives, but a new study pinpoints the cow-calf stage as a major contributor of greenhouse gases during beef production. In a new paper for the Journal of Animal Science, scientists estimate greenhouse gas emissions from beef cattle during different stages of life. They show that, depending on which production system farmers used, beef production has a carbon footprint ranging from 10.7 to 22.6 kg of carbon dioxide equivalent per kg of hot carcass weight. According to study co-author Frank Mitloehner, an associate professor in the Department of Animal Science at UC Davis, one source of greenhouse gases was surprising. “If you look at everything that contributes to greenhouse gases through the beef supply chain, then it is the cow-calf that produces the greatest greenhouse gases,” Mitloehner said. In the cow-calf phase, the cow gives birth and nurses the calf until the calf is six to 10 months old. During this time, the cow eats rough plants like hay and grasses. The methane-producing bacteria in the cow’s gut thrive on these plants. “The more roughage is in the diet of the ruminant animal, the more methane is produced by the microbes in the gut of the ruminant, and methane comes out the front end,” Mitloehner said.

In feedlots, by contrast, cattle eat mostly corn and grains, which the methane-producing bacteria cannot use as effectively. Methane is one of the most important greenhouse gases. Methane has a greater capacity to trap heat in the atmosphere than carbon dioxide. The beef industry has been paying close attention to greenhouse gas emissions in recent years. “We are doing a lot to measure and mitigate our impact,” said Chase Adams, director of communications for the National Cattlemen’s Beef Association. In a 2011 paper for the Journal of Animal Science, researcher Jude Capper showed that the beef industry today uses significantly less water and land than 30 years ago. The industry has also reduced its carbon footprint by 16.3 percent per billion kilograms of beef produced. According to Mitloehner, beef producers can further reduce their carbon impact by using new technologies like growth promotants. However, consumers are often uncomfortable with these methods, and they choose organic beef or beef with reduced amounts of growth promotants. “The technologies many consumers are critical of are those that help us receive the greatest environmental gains,” Mitloehner said.

Eurek Alert! Medicine
February 19, 2013

Original web page at Eurek Alert! Medicine

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Cows fed flaxseed produce more nutritious dairy products

Dairy cows that are fed flaxseed produce more nutritious milk, according to a new study by Oregon State University. Their milk contained more omega-3 fatty acids and less saturated fat, the study found. Diets high in saturated fat can increase cholesterol and cause heart disease, while those rich in omega-3 and other polyunsaturated fatty acids may reduce the risk of heart disease, studies have shown. Traditional cattle feed mixtures of corn, grains, alfalfa hay and grass silage result in dairy products with low concentrations of omega-3 and other polyunsaturated fats, according to Gerd Bobe, the lead scientist on the study, which has been published online in the Journal of Dairy Science. Ten pregnant cows at OSU’s dairy were fed different amounts of flaxseed — up to seven percent of their daily diet. Researchers attempted to pinpoint the amount of flaxseed that would maximize the amount of omega-3 in milk and dairy products without negatively affecting their production and texture. “We were looking for a sweet spot,” said Bobe, an expert in human and animal nutrition. “Too much of a good thing can be bad, especially when trying to maintain consistency with dairy products.”

Collaborators in OSU’s food science and technology department assisted in turning milk into butter and fresh cheese, which were then tested for texture and nutritional composition. The study found that feeding cows up to six pounds of extruded flaxseed improved the fat profile without negatively affecting the production and texture of the milk and other dairy products. Extrusion presses raw ground flaxseed into pellets with heat. At six pounds per day, saturated fatty acids in whole milk fat dropped 18 percent, poly-unsaturated fatty acids increased 82 percent, and omega-3 levels rose 70 percent compared to feeding no flaxseed. Similar improvements were observed in butter and cheese. Still, saturated fat accounted for more than half of the fatty acids in the dairy products while the increase in polyunsaturated fats compromised no more than nearly nine percent of the total. Researchers also noted that the refrigerated butter was softer and less adhesive thanks to fewer saturated fatty acids. Also, the cows produced the same amount of milk while eating flaxseed. Although flaxseed costs more than traditional cattle feeds, Bobe hopes that it still could be an affordable feed supplement for cows because products enriched with omega-3 can sell for a premium at the grocery store. “Many consumers already show a willingness to pay extra for value-added foods, like omega-3 enriched milk,” he said. One thing is for sure, he said: Dairy farmers will have no trouble convincing cows to eat flaxseed. “They loved it. They ate it like candy,” he said.

Science Daily
February 19, 2013

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Beef industry, consumers to be affected by cattle production decreases in 2013

Beef production in the United States is expected to decrease 4.8 percent in 2013, the second largest year-over-year decrease in 35 years, trailing only the 6.4 percent drop in 2004. The reason is a combination of mostly steady carcass weights and a projected 5 percent or more decrease in cattle slaughter, said Derrell Peel, Oklahoma State University Cooperative Extension livestock marketing specialist. “Many analysts expect the 2013 numbers to be followed by a 2014 decrease of 4.5 percent or more,” he said. “These two years would represent the largest percentage decrease since the late 1970s.” Beef production in 2012 decreased by approximately 1.1 percent compared to 2011 with a 3.3 percent decrease in slaughter, which was partially offset by a 2.3 percent increase in carcass weights. However, the effect on consumption of beef does not always match the change in production. Domestic per capita consumption will depend on production levels but must be adjusted for beef imports and exports.

“In 2013, per capita beef consumption is expected to drop 3.5 percent, less than the production decrease because beef imports will increase and beef exports will decrease,” Peel said. “The decrease in per capita beef consumption in 2013 should be similar to the year-over-year decrease in 2011 compared to 2010.” In 2011, domestic per capita beef consumption decreased 3.8 percent, in large part because of a sharp increase in beef exports despite a minimal decrease in beef production. Though 2004 had a sharper production decrease, per capita beef consumption that year increased nearly 2 percent because of a sharp drop in beef exports, largely attributed to the first case of Bovine spongiform encephalopathy, also referred to as BSE, in the United States. “Beef consumption may drop more sharply in 2014 with a 5 percent decrease in per capita consumption compared to the lower 2013 level,” Peel said. “Furthermore, these decreases in beef production and consumption almost certainly imply higher wholesale and retail beef prices, although other factors will impact the price response to lower supplies.”

Choice boxed beef has been trapped in a narrow range between $193 and $198 per hundredweight for the past three months. Retail beef prices were flat to slightly lower through much of 2012 but did jump sharply in November. “In 2011, a similar decrease in beef consumption resulted in a 15 percent increase in boxed beef prices and a nearly 10 percent increase in retail prices,” Peel said. “Total meat consumption decreased about 2 percent in 2011 and a similar 2.1 percent decrease is expected in 2013 with both pork and broiler consumption expected to drop approximately 1.5 percent each.” The pressure for higher boxed beef prices will increase significantly with an expected 4.5 percent decrease in beef production in the first quarter of 2013. Choice boxed beef should move above $200 per hundredweight in the next few weeks. Beyond that, Peel believes it will be a question of how much and how fast retailers can pass along the higher wholesale prices to consumers. “It is not really a question of whether retail prices will go up but rather a question of how much and how fast,” he said. “Beef demand remains the biggest unknown in the beef industry. Time will tell just how severe the squeeze will be on industry margins in 2013.” Cattle and calves represent the number one agricultural commodity produced in Oklahoma, accounting for 46 percent of total agricultural cash receipts and adding approximately $2 billion to the state economy, according to National Agricultural Statistics Service data. NASS data indicates Oklahoma is the nation’s fifth-largest producer of cattle and calves, with the third-largest number of cattle operations in a state.

Science Daily
February 5, 2013

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Brain inflammation likely key initiator to prion and Parkinson’s disease

In a recent publication, researchers of the Computational Biology group at the Luxembourg Centre for Systems Biomedicine showed that neuro-inflammation plays a crucial role in initiating prion disease. Prion diseases represent a family of neurodegenerative disorders associated with the loss of brain cells and caused by proteins called prions (derived from ‘protein’ and ‘infection’). The diseases are found in both humans and animals, such as Creutzfeld-Jakob disease and mad cow disease respectively. Although mostly harmless, prions can transform into infectious agents, which accumulate in the brain and destroy the nervous tissue. But how exactly does the accumulation of prions cause destruction of the brain? “Understanding the process by which prions destroy neurons is critical for finding a cure for prion disease”, says Isaac Crespo, first author of the publication. He and his colleagues tackled this question with a computational approach: They ran their own computer programmes on experimental data generated by other research groups, and identified a set of 16 proteins that seems to control the onset of the disease. Interestingly, almost all of these proteins have known functions in neuro-inflammation. “What we consider remarkable and constitutes our main finding, is the key role that neuro-inflammation plays in initiating prion disease. This finding is not only relevant for prion diseases, but also for other ‘protein misfolding diseases’ such as Parkinson’s and Alzheimer diseases” says Prof. Dr. Antonio del Sol, group leader of the Computational Biology group.

Science Daily
December 11, 2012

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A cow in New Zealand has been genetically modified to produce hypoallergenic milk

Two genetically engineered farm animals reported today illustrate how far from Frankenstein’s stitched-together monster animal biotechnology has come. One of those animals, a cow, secretes milk that lacks an allergy-inducing protein because researchers accurately blocked its production using the technique of RNA interference. And in pigs, scientists have used an enzyme called a TALEN to scramble a gene that would normally help remove cholesterol. RNA interference (RNAi) and TALENs are more accurate at targeting the gene in question than are earlier genetic engineering techniques. For years, researchers tried to remove the allergy-inducing milk protein beta-lactoglobulin from cow’s milk, which can cause diarrhea and vomiting in some toddlers. They tried replacing the gene encoding beta-lactoglobulin with a defective form, but this proved nearly impossible because the techniques available to introduce foreign genes into animal genomes were not precise, and misplaced genes failed to express themselves correctly.

In 2006, scientists at AgResearch in Hamilton, New Zealand began to experiment with molecules that interfere with the messenger RNA go-between that enables translation of a gene into protein. In mice, they discovered a short chunk of RNA, called a microRNA, that targeted beta-lactoglobulin messenger RNA directly to prevent its translation. They inserted DNA encoding a version of this microRNA into the genome to create genetically modified cow embryos that they hoped would grow into cows without the allergen in their milk. Out of 100 embryos, one calf yielded beta-lactoglobulin-free milk. “This isn’t a quick process,” says Stefan Wagner, a molecular biologist at AgResearch. That’s why it has taken so long to succeed in making an allergen-free cow, he says. Wagner says that TALENs, which were not readily available when he began his research, might speed up the process, and that the team plans to use them to eliminate beta-lactoglobulin. RNAi cannot eliminate the protein completely because some messenger RNA slips past the blockade, but each TALEN targets a specific DNA sequence in the genome and cuts it. As the body repairs the break, mutations are often introduced that render the targeted gene non-functional. “The TALEN technology is staggeringly easy, quick, and leaves no mark in the genome,” says Bruce Whitelaw, a molecular biologist at the Roslin Institute near Edinburgh in the United Kingdom, who contributed to the work in pigs. “In essence, we are just mimicking an evolutionary process with precise, man-made editors.”

His team used TALENs to disrupt genes encoding low-density lipoprotein (LDL) receptors. Without these receptor proteins to remove cholesterol-containing LDLs from the blood, LDLs build-up and lead to atherosclerosis. Pigs with this condition may be reliable models of human atherosclerosis in biomedical research. The TALEN-modified pig is not the first model of human heart disease, but the technique makes genetic engineering less costly and more efficient. “I’d be exaggerating if I said that pigs and cows can now be thought of as big mice, but we are moving in that direction,” says Heiner Niemann, a bioengineer at the Institute of Farm Animal Genetics in Neustadt, Germany. The excitement surrounding these technological advances is bittersweet, however. Originally, engineered animals were produced with the aim of making food safer, healthier and more abundant. Yet despite years of investment, almost no animal has been approved by regulatory agencies around the world. Wagner says he has not tasted the milk from his special cow because he’s not permitted to under New Zealand law. “We must restrict our research to scientific analysis,” he says. “The current climate for animal biotech is not very good, and therefore, we are nowhere near getting this to the consumer.”

Nature
October 16, 2012

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Excessive summertime heat can shorten gestation time for beef cattle

Southern Plains cow-calf producers with fall-calving herds should be watching out for any incidence of premature births this August. Research conducted by Oklahoma State University’s Division of Agricultural Sciences and Natural Resources indicates that excessively hot summertime temperatures — all too normal for the south-central region of the United States — can shorten the gestation length of beef cows. “Producers may need to adjust their herd management so as to help cows that require birthing assistance; OSU research shows that cows exposed to 90 degrees Fahrenheit or greater during the last two weeks of gestation calve an average of four days earlier than what is considered normal,” said Bob Wettemann, OSU Regents professor and animal science researcher. Wettemann added some calves in the OSU studies were born two weeks early in August, and showed good survival rates provided the newborn calves had access to sufficient shade. “It’s important that newborns be able to cool down and not be stressed,” he said. The OSU animal science studies strengthen consideration for cattle producers to use a fall-calving system with first-calf cows, instead of a spring-calving system. “Lighter birth weights for fall-calving first-calf cows should decrease difficulties associated with small cows giving birth to large calves,” Wettemann said.

In most mammals, the fetus determines when the birth will occur. There is essentially a “time clock” in the calf that determines when the process is going to be initiated. Recent scientific studies demonstrate that high temperatures can speed up the “time clock” during the last two weeks of gestation, because of hormonal changes in the cow and fetus. “This is not automatically a bad thing as it can provide certain animal health benefits, but it does require earlier observation of cows during late gestation,” Wettemann said. “When used in conjunction with selection of bulls whose genetics promote lower birth weights, producers potentially can see increased calf survival, and getting a live calf on the ground is the whole point.” Cattle and calves are the number one agricultural commodity produced in Oklahoma, accounting for 46 percent of total agricultural cash receipts and adding approximately $2 billion annually to the state economy, according to National Agricultural Statistics Service data.

Science Daily
September 4, 2012

Original web page at Science Daily

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Officials act to secure cattle-plague virus

Rinderpest, a devastating cattle disease, has not been seen in the wild for a decade, but it lives on in scores of labs. Twelve months after the world celebrated the success of a years-long vaccination campaign that made rinderpest only the second disease after smallpox to be eradicated, animal-health authorities are turning to the next task: making sure that a lab release — accidental or intentional — doesn’t lead to a resurgence. Rinderpest is as deadly to cattle as highly pathogenic H5N1 avian flu is to chickens. In past decades, outbreaks ripped through herds and wiped out up to 90% of animals, often leaving famine, and sometimes war, in their wake. “Its eradication is a huge, huge, achievement that has happened largely under the radar of most of the virology and scientific community,” says David Ulaeto, a member of a seven-person multidisciplinary Joint Advisory Committee (JAC) on rinderpest that was set up to consolidate the eradication by the Rome-based Food and Agriculture Organization of the United Nations (FAO) and the Paris-based World Organisation for Animal Health (OIE).

This October, the JAC will probably issue the first of a series of guidelines for an international oversight system. With the help of ad hoc expert groups, the JAC would approve official repositories of the virus and ensure that they meet tough biosafety standards. The committee would also approve all future research on live rinderpest virus to ensure that its benefits outweigh the risks. The FAO and OIE don’t have the authority to impose such measures on member states, but last year, countries gave the organizations a mandate by endorsing a moratorium on research and declaring that the remaining virus samples should be destroyed or shipped to approved high-security labs. The approach is modelled on the post-eradication phase of the smallpox campaign, which saw the number of labs holding the virus reduced from 76 in 1976 to just 2 in 1984. To identify labs that might still hold rinder­pest virus, the FAO carried out extensive literature searches, liaised with ministries of agriculture and veterinary services worldwide, and wrote “to virtually everyone they could think of”, says Ulaeto. By last week, the FAO and OIE had identified some 40 labs. “They were a bit surprised at how many laboratories did have virus,” he says.

The list remains confidential, but it includes labs from some 20 countries, thought to be mainly in Africa, the Middle East and Asia, where rinderpest outbreaks were common until recently, and a handful of established rinderpest research centres, such as the Institute for Animal Health in Pirbright, UK, and the Plum Island Animal Disease Center in New York state. One worrying aspect was that some virus samples were found to be held in facilities that had inadequate biosafety levels. Fears of an accidental release are grounded in experience. After smallpox was eradicated, a lab accident in Birmingham, UK, resulted in two infections and one death. And an accidental release of foot-and-mouth virus from the Pirbright facility, which houses a high-biosecurity, world-reference laboratory for both foot-and-mouth and rinderpest, caused an outbreak in the United Kingdom in 2007. Active research on rinderpest has waned as the disease has been brought under control over the past few decades, says Michael Baron, a rinderpest researcher at the Pirbright centre. He and others say that the biggest threat is from long-forgotten samples of virus from past research programmes, and serum and other samples collected for diagnostic or other purposes, that may be lurking in lab freezers. Rinderpest vaccine strains, which are stocked in many countries and consist of live attenuated virus, are also a concern. In theory, they could revert to wild type and cause disease outbreaks.

Until the world is certain that rinderpest is gone for good, vaccine strains will probably need to be maintained in high-security labs in several regions so that they can be shipped swiftly to any outbreak, says Baron. But he says that just a couple of pure-research labs would be enough to pursue the valuable scientific opportunities that rinderpest still offers. Although the virus is closely similar to the human measles virus, for example, cattle don’t catch measles and humans don’t catch rinderpest. Understanding why this is so could provide insight into the pathology and basic biology of viruses, Baron says. Of more immediate interest, investigators would also like to know whether vaccines can be developed against another related virus, the sheep and goat disease called peste des petits ruminants, that might also protect against rinderpest. That would eliminate the need to keep any stocks of live attenuated rinderpest virus at all. Baron’s home lab contains more than 100 different rinderpest virus isolates, which he says represent “basically the history of the disease”. He intends to sequence them all in the next few years — so that they can be recreated if ever needed — and then destroy them.

Nature
August 21, 2012

Original web page at Nature

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Novel vaccine for strain of foot-and-mouth disease

One of the most economically devastating diseases in the world for those who raise cows, sheep, pigs, goats, deer and other cloven-hoofed animals is foot and mouth Disease (FMD). This incredibly contagious and fast-spreading disease causes fever, blisters on the feet and mouth (hence the name), loss of appetite, drooling, and lameness. Most herds affected are culled, as in the case of the 2001 outbreak in Great Britain when over 10 million animals had to be destroyed. Traditional vaccines for FMD typically have three problems: first, there are so many different strains of the FMD virus that you must have a very well-matched vaccine to have any effect; second, traditional vaccines contain live FMD virus so they cannot be produced in the United States, and, third, depending on a vaccine’s quality, it can be nearly impossible to determine whether an animal is actually infected, or has simply been exposed to the vaccine. Unless one can differentiate between vaccinated and infected animals, those animals vaccinated outside the U.S. with the traditional vaccine would be prohibited from entering any country that is designated FMD free. The United States has been FMD-free since 1929, but that is no guarantee that the disease will not strike again, as the UK learned in 2001 after being FMD-free for 34 years.

Now, at the Department of Homeland Security Science and Technology Directorate’s high-containment Plum Island Animal Disease Center (PIADC), located off the tip of Long Island, scientists have produced a molecular vaccine against one strain of FMD, that 1) does not use a live FMD virus for vaccine manufacture, and, 2) can be used to differentiate an infected from inoculated animal using common diagnostic tests. The new vaccine produces only the virus coat particles, which form empty viral capsids, and not the entire genome of the virus; thus it lacks the infectious viral nucleic acids. When the vaccine is injected into the animal the resulting empty viral capsids trigger a protective immune response. “The absence of the nucleic acids of the real virus allows us to differentiate between vaccinated and infected animals,” said Grubman. “This is critical when determining that an animal is free of infection after an FMD outbreak. Now it will no longer be necessary to destroy all the animals in a herd when just a few become infected.”

The development of the vaccine was a team effort that required new scientific discoveries in order to work properly. Dr. John Neilan, the Branch Chief of the DHS Targeted Advanced Development Branch at PIADC, developed a way to address the immune response to the vaccine, which made it possible to achieve the level of effectiveness required for a USDA license. The vaccine has been granted conditional license for use in cattle by the USDA Animal and Plant Health Inspection Service’s Center for Veterinary Biologics. Under the conditional license, the product may be distributed should the need for it arise, as authorized by federal emergency management officials within USDA. APHIS issued the conditional license to Antelope Valley Bios, Inc., who manufactured the vaccine under a contract from GenVec.

The FMD virus, noted since at least the 16th century, survives in lymph nodes and bone marrow. Large amounts of the virus are found in all body secretions and excretions and every time an infected animal breathes out it releases large amounts of infectious virus, exposing other animals. FMD virus can survive on the ground for extended periods, and can be carried in contaminated feed, manure, on the tires of vehicles and on the shoes and clothes of people. It has been documented to spread by being carried with the wind over long distances. The most common route of introduction of FMD into a country has been through feeding contaminated meat product scraps to pigs, as was the case in the devastating 2001 outbreak in the United Kingdom. There are seven known serotypes and more than 60 subtypes of the FMD virus, and there is no universal vaccine against the disease. Potential cost of an FMD outbreak in United States could exceed $50 billion. FMD is present July 3 in Africa, the Middle East, Asia, and parts of South America.

Science Daily
July 24, 2012

Original web page at Science Daily

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Study finds ‘mad cow disease’ in cattle can spread widely in ANS before detectable in CNS

Bovine spongiform encephalopathy (BSE, or “mad cow disease”) is a fatal disease in cattle that causes portions of the brain to turn sponge-like. This transmissible disease is caused by the propagation of a misfolded form of protein known as a prion, rather than by a bacterium or virus. The average time from infection to signs of illness is about 60 months. Little is known about the pathogenesis of BSE in the early incubation period. Previous research has reported that the autonomic nervous system (ANS) becomes affected by the disease only after the central nervous system (CNS) has been infected. In a new study published online in the August issue of The American Journal of Pathology, researchers found that the ANS can show signs of infection prior to involvement of the CNS. “Our results clearly indicate that both pathways are involved in the early pathogenesis of BSE, but not necessarily simultaneously,” reports lead investigator Martin H. Groschup, PhD, Institute for Novel and Emerging Infectious Diseases at the Friedrich-Loeffler-Institut, Riems, Germany.

To understand the pathogenesis of BSE, fifty-six calves between four and six months of age were infected orally with BSE from infected cattle. Eighteen calves were inoculated orally with BSE-negative material from calf brainstem as controls. The study also included samples collected from a calf that had died naturally of BSE. Tissue samples from the gut, the CNS, and the ANS were collected from animals every four months from 16 to 44 months after infection. The samples were examined for the presence of prions by immunohistochemistry. Samples were also used to infect experimental mice that are highly sensitive to a BSE infection. A distinct accumulation of the pathological prion protein was observed in the gut in almost all samples. BSE prions were found in the sympathetic ANS system, located in the thoracic and lumbar spinal cord, starting at 16 months after infection; and in the parasympathetic ANS, located in the sacral region of the spinal cord and the medulla, from 20 months post infection. There was little or no sign of infection in the CNS in these samples. The sympathetic part of the ANS was more widely involved in the early pathogenesis than its parasympathetic counterpart. More bovines showing clinical symptoms revealed signs of infection in the sympathetic nervous system structures at a higher degree than in the parasympathetic tissue samples. The earliest detection of BSE prions in the brainstem was at 24 months post infection. However, infection detected in the spinal cord of one animal at 16 months post infection suggests the existence of an additional pathway to the brain.

“The clear involvement of the sympathetic nervous system illustrates that it plays an important role in the pathogenesis of BSE in cattle,” notes Dr. Groschup. “Nevertheless, our results also support earlier research that postulated an early parasympathetic route for BSE.” The results, Dr. Groschup says, indicate three possible neuronal routes for the ascension of BSE prions to the brain: sympathetic, parasympathetic, and spinal cord projections, in order of importance. “Our study sheds light on the pathogenesis of BSE in cattle during the early incubation period, with implications for diagnostic strategies and food-safety measures.”

EurekAlert! Medicine
July 24, 2012

Original web page at EurekAlert! Medicine

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Milking cows 7000 years ago

The first unequivocal evidence that humans in prehistoric Saharan Africa used cattle for their milk nearly 7,000 years ago is described in research by an international team of scientists, led by the University of Bristol, UK, published June 20 in Nature. By analysing fatty acids extracted from unglazed pottery excavated from an archaeological site in Libya, the researchers showed that dairy fats were processed in the vessels. This first identification of dairying practices in the African continent, by prehistoric Saharan herders, can be reliably dated to the fifth millennium BC. Around 10,000 years ago the Sahara Desert was a wetter, greener place; early hunter-gatherer people in the area lived a semi-sedentary life, utilising pottery, hunting wild game and collecting wild cereals. Then, around 7,000-5,000 years ago as the region became more arid, the people adopted a more nomadic, pastoral way of life, as the presence of cattle bones in cave deposits and river camps suggests. Domesticated animals were clearly significant to these people: the engraved and painted rock art found widely across the region includes many vivid representations of animals, particularly cattle. However, no direct proof that these cattle were milked existed — until now.

Researchers at the Organic Geochemistry Unit in Bristol’s School of Chemistry, with colleagues at Sapienza, University of Rome, studied unglazed pottery dating from around 7,000 years ago, found at the Takarkori rock shelter in the Tadrart Acacus Mountains, Libya. Using lipid biomarker and stable carbon isotope analysis, they examined preserved fatty acids held within the fabric of the pottery and found that half of the vessels had been used for processing dairy fats. This confirms for the first time the early presence of domesticated cattle in the region and the importance of milk to its prehistoric pastoral people. Julie Dunne, a PhD student in Bristol’s School of Chemistry and one of the authors of the paper said: “We already know how important dairy products such as milk, cheese, yoghurt and butter, which can be repeatedly extracted from an animal throughout its lifetime, were to the people of Neolithic Europe, so it’s exciting to find proof that they were also significant in the lives of the prehistoric people of Africa. “As well as identifying the early adoption of dairying practices in Saharan Africa, these results also provide a background for our understanding of the evolution of the lactase persistence gene which seems to have arisen once prehistoric people started consuming milk products.

“The gene is found in Europeans and across some Central African groups, thus supporting arguments for the movement of people, together with their cattle, from the Near East into eastern African in the early to middle Holocene, around 8,000 years ago.” Co-author Professor Richard Evershed of Bristol’s School of Chemistry, added: “While the remarkable rock art of Saharan Africa contains many representations of cattle — including, in a few cases, depictions of the actual milking of a cow — it can rarely be reliably dated. Also, the scarcity of cattle bones in archaeological sites makes it impossible to ascertain herd structures, thereby preventing interpretations of whether dairying was practiced. “Molecular and isotopic analysis of absorbed food residues in pottery, however, is an excellent way to investigate the diet and subsistence practice of early peoples. It’s an approach my colleagues and I have previously applied to successfully determine the chronology of dairying, beginning in the Fertile Crescent of the Near East and spreading across Europe.”

Science Daily
July 10, 2012

Original web page at Science Daily

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Bovine TB disguised by liver fluke

Bovine tuberculosis (bTB) could be spreading across Britain because the most widely used test for the disease is ineffective when cattle are infected with a common liver parasite. The liver fluke Fasciola hepatica was already known to affect the standard skin test for bTB, but it was unclear whether the fluke stopped the disease developing or merely hid the symptoms. A study published today in Nature Communications suggests that the latter is more likely, and that the effect is significant. It estimates that around a third of bTB cases in England and Wales are undiagnosed because the test is less sensitive in cattle infected with the fluke. Researchers tested milk from dairy herds across England and Wales for antibodies against F. hepatica, an indication of infection, and added the data to an existing model of bTB transmission. If they assumed that a fluke infection inhibited bTB detection, they achieved a closer match between the model and actual bTB detection rates. The authors suggest that the fluke may alter the production by T lymphocytes — key cells in the immune system — of the protein interferon-γ, which is crucial to a genuine result in both the skin test and the second most common test for bTB, the interferon-γ release assay (IGRA) blood test.

Diana Williams, an infectious disease specialist at the University of Liverpool, UK, and an author of the paper, says the result helps explain why bTB is still endemic across England and Wales. “Everyone is aware that current methods aren’t detecting early enough or with enough sensitivity,” she says. “We need to look at better control of fluke.” But the Department for Environment, Food and Rural Affairs, which is responsible for bTB control in Britain, questions whether the liver fluke hides infections. “Cattle carcasses are inspected in abattoirs and we would see evidence of TB in the slaughtered animals if this was the case,” a spokesperson said in a statement. The authors of the Nature Communications study hypothesize that cows display fewer symptoms because the fluke alters their immune response. A 2007 study supports this interpretation, showing that animals with preexisting tuberculosis had reduced sensitivity to the skin test when they were infected with liver fluke. The United States, Canada and Australia have eradicated bTB, but Britain and Ireland have struggled to control it. The disease costs the UK government around £100 million (US$158 million) a year. Control relies on testing cattle for bTB before they are moved between farms; animals that test positive are destroyed and the herd is retested. But the strategy isn’t working. Cases have increased over the past 25 years and new infection sites crop up long distances from existing hotspots.

Eradicating liver fluke could increase the sensitivity of the skin test and allow better control of infected cattle, but this poses its own difficulties. Farmers can keep cattle away from damp fields that are home to the fluke’s snail host, but treating infected dairy cattle is complicated. In 2010 the European Union (EU) banned most flukocide drugs because they leave toxic residues in milk. The milk from cows that receive the remaining two allowed drugs is undrinkable for three days after treatment. Badgers have been blamed for spreading bTB between farms, and after a fraught debate the UK government last year announced a badger cull in England. (The Welsh government backed out of the trial last month.) David Williams, chairman of the UK charity, the Badger Trust, believes the decision to cull should be reassessed in light of the new research. “The unreliability allows disease to remain undetected, and badgers are blamed when infected cows are found later,” he says. “We have frequently queried the accuracy of testing, only to be told it is acceptable by EU standards and is the best test available.” Although more experiments are needed to confirm the precise interaction between flukes and the skin test, Dirk Werling, an immunologist at the Royal Veterinary College in Hatfield says there could be implications beyond cattle. Human liver flukes are rife in tropical and sub-tropical regions, and bTB causes 10% of human tuberculosis deaths in Africa. “We know that a similar immune mechanism exists in humans,” he says. “The potential consequences of these observations could potentially be quite severe, not only for the farm animals, but also for people in third-world countries.” Liver fluke could also explain epidemiological mysteries, such as why bTB has never gained a foothold in north-west England. “Our knowledge has holes in it,” says William Wint, an ecologist at the University of Oxford, UK, who has become frustrated by the badger-centric debate. “If this can make people look more at epidemiology than politics, that would be marvellous.”

Nature
June 12, 2012

Original web page at Nature

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Seroprevalence of Schmallenberg virus antibodies among dairy cattle, the Netherlands, winter 2011–2012

Infections with Schmallenberg virus (SBV) are associated with congenital malformations in ruminants. Because reporting of suspected cases only could underestimate the true rate of infection, we conducted a seroprevalence study in the Netherlands to detect past exposure to SBV among dairy cattle. A total of 1,123 serum samples collected from cattle during November 2011–January 2012 were tested for antibodies against SBV by using a virus neutralization test; seroprevalence was 72.5%. Seroprevalence was significantly higher in the central-eastern part of the Netherlands than in the northern and southern regions (p<0.001). In addition, high (70%–100%) within-herd seroprevalence was observed in 2 SBV-infected dairy herds and 2 SBV-infected sheep herds. No significant differences were found in age-specific prevalence of antibodies against SBV, which is an indication that SBV is newly arrived in the country. During the last 2 weeks of August and the first 2 weeks of September 2011, dozens of veterinary practitioners in the Netherlands reported to a monitoring help desk (GD Veekijker) that several dairy herds with cows showed a sudden decrease in milk production, watery diarrhea, and occasional fever. The affected animals recovered, and extensive bacteriologic, virologic, and parasitologic testing of feces and blood samples of sick cows did not reveal an infectious cause for the clinical signs. Similar problems were reported at about the same time in Germany, and on November 18, 2011, the Friedrich Loeffler Institute (Greifswald, Germany) reported the detection of a novel orthobunyavirus that could be the cause of the clinical problems. Real-time reverse transcription PCR (RT-PCR), made available by the Friedrich Loeffler Institute, was used to test stored blood samples (N = 50) from the clinically diseased cattle in the Netherlands; 36% had positive test results. Since then, the virus has also been associated with congenital malformations in young animals (lambs, goat kids, and calves). The new virus is provisionally called Schmallenberg virus (SBV), or Shamonda-like virus. It is a RNA virus and shows 97% identity with Shamonda virus (SHAV) (small gene segment), 71% identity with Aino virus (medium gene segment), and 69% identity with Akabane virus (AKAV) (large gene segment). All these viruses are part of the Simbu serogroup of the family Bunyaviridae, genus Orthobunyavirus. The Simbu serogroup is composed of several arthropod-borne viruses (arboviruses, including SHAV, AKAV, and Aino virus) transmitted by Culicoides spp. biting midges and mosquitos. SHAV was initially isolated from cattle and Culicoides spp. biting midges in Nigeria in the 1960s. In 2002, SHAV emerged in Japan and was isolated from Culicoides spp. biting midges and sentinel cattle. Japan has been considered an area to which several Simbu group viruses have been endemic in cattle since the 1970s.

In the Netherlands, reporting of suspected cases of SBV infection in animals (occurrence of arthrogryposis hydranencephaly syndrome in calves, lambs, and goat kids) is obligatory; a report is followed by confirmatory testing of brain tissue samples by RT-PCR. However, the observed suspected cases are likely an underestimation of the true rate of infection; in addition, infected livestock may give birth to healthy young animals, adding to the underestimation of the true rate of infection. Therefore, serodiagnostic studies are needed to detect past exposure to SBV in ruminant populations in the affected countries. Within weeks after the start of the SBV epidemic, a virus neutralization test (VNT) was developed at the Central Veterinary Institute (CVI). This test made it possible to quickly execute a seroprevalence study of antibodies against SBV in dairy cattle in the Netherlands.

Emerging Infectious Diseases
May 29, 2012

Original web page at Emerging Infectious Diseases

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California BSE prion comes with a different twist

Reports of ‘mad cow’ disease in the United States erupted in the news this week after the US Department of Agriculture (USDA) confirmed that the remains of a California dairy cow had tested positive for bovine spongiform encephalopathy (BSE). This marks the fourth case of BSE identified in the US, and the first case in six years. In spongiform encephalopathy diseases, abnormally folded prion proteins accumulate in the brain, causing other proteins to deform as well. BSE has proved to be unusually adept at jumping between species; humans exposed to BSE can develop its human counterpart: Creutzfeldt-Jakob disease (CJD). In a statement released on 24 April, Karen Ross, Secretary of the California Department of Food and Agriculture said, “The detection of BSE shows that the surveillance program in place in California and around the country is working.” Food safety advocates such as Yonkers, New York, -based Consumers Union say it’s a warning sign that surveillance is inadequate and needs to be stepped up. Ross’s statement also makes a point of noting a key feature of this particular case: The infected cow carried what is known as ‘L-type’ BSE, a version of the disease that has not been detected before in the US and has so far not been associated with transmission through animal feed. As the policy debate over testing rumbles on, here is a short guide to what is known and not known about this rare strain and its unexpected appearance.

After brain tissue samples turned up inconclusive results in California, scientists at the USDA’s Veterinary Research Laboratories in Ames, Iowa ran two additional biochemical tests and got positive results for BSE. The second technique, western blotting, separates proteins based on their molecular weight to create a pattern on a gel. L-type prions have low weights, and another atypical strain, H-type prions have high weights compared to classic (C) strains. This sample produced a clear L-type pattern, said Mark Hall, head of the pathology, parasitology, and entomology section at Ames. In addition to weighing less, L-type strains also produce different lesion profiles in the brain. Both H and L types are extremely rare and found in older cattle, with only around 30 reported cases each worldwide. Perhaps this contributes to the fact that we don’t know much about them. “Right now, the full pathogenesis is not well characterized,” says Hall of L-type. Unlike their classical counterparts, “past studies and current diagnostic tests to detect ruminant DNA and RNA in feed haven’t found atypical variants,” says Jim Cullor, a veterinarian at the University of California at Davis.

“There is some evidence in primates and transgenic mice that it seems to spread faster – meaning it maybe more virulent – but we don’t know how representative these models are of the disease in humans,” says Linda Detwiler, a clinical professor at Mississippi State University’s College of Veterinary Medicine. Whether or not L-type could jump species without direct injection into the brain remains unclear, but so far it can transmit to transgenic humanized, ovinized (modified to genetically mimic sheep), bovinized, and normal mice, as well as macaques in the lab. “We do know that L-type can transmit from one cow to another through injection in the brain,” says Detwiler. “Long term studies are beginning to look at whether or not it’s capable of transmission orally through feed, but we don’t have the data yet.” Whether these strains have been around for a long time or recently developed is still unknown. “No one knows the origin at this point,” says Detwiler. “It might be sporadic, similar to sporadic types of Creutzfeldt-Jakob disease in humans. It might be some kind of genetic mutation, or it could be a modification of classical BSE or TSE.” In a 2008 study, out of all known cases of atypical BSE, only one contained a genetic mutation. So, a mutant cause can’t be ruled out and could arise in countries that have never seen BSE. In humans, sporadic cases of CJD – those that aren’t caused by transmission from cattle – occur at random in humans without a clear cause.

The USDA bans cow material in cow feed and “specific risk material” – meaning bone, brain, and other organs where the disease persists – from all livestock feed. “The L-type’s infectivity alone reinforces the need for regulations,” says Detwiler. “It’s really important to monitor any emerging disease around the world so that we can change our policies if we need to.” Some feel that the regulations aren’t enough. Michael Hansen, a senior staff scientist with Consumer’s Union, notes that only .13% of the 30 million cattle that go to slaughter annually in the US are tested. “I would argue that’s not enough,” says Hansen. “The feed ban is not a firewall.” The USDA has sent samples to official World Animal Health (OIE) reference labs in Canada and Great Britain. An on-site farm investigation may reveal more about the source and potential extent of infection. Whether or not the case produces any astounding revelations in the coming weeks, it has already underscored the many general unknowns that researchers face when it comes to L-type. “It’s important to look at whether it can transmit orally into to cattle or other species that consume feed, and to figure out where infection occurs in case we need to look for different high risk material,” says Detwiler. “With continued research and epidemiology studies, we’ll get more clues.”

Nature
May 15, 2012

Original web page at Nature

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Schmallenberg virus in calf born at term with porencephaly

From the end of August through the end of October 2011, a clinical syndrome involving adult cattle and the fetuses of pregnant cows emerged in the border area between the Netherlands and North Rhine-Westphalia, Germany. The syndrome was characterized by nonspecific clinical signs (fever, decreased milk production), severe diarrhea, and some abortions. A metagenomic analysis was conducted on pooled samples from cattle with acute signs on a farm in the city of Schmallenberg, Germany. The analysis detected nucleotide sequences homologous to arthropod-borne Akabane, Aino, and Shamonda viruses, all belonging to the family Bunyaviridae, genus Orthobunyavirus, and Simbu serogroup. Real-time PCR detected the genomic RNA of the new and emerging virus, tentatively designated Schmallenberg virus (SBV), in the blood of adult cattle, abdominal fluid of a stillborn calf, and brains of lambs born with birth defects on dozens of farms in the Netherlands, Germany, and Belgium. No data are yet available to predict how the emerging virus might affect the cattle industry. We report the case of a 1-week old calf with severe central nervous system (CNS) lesions probably caused by in utero infection with the new virus.

In Belgium in January 2012, a Belgian Blue multiparous cow gave birth to a 45-kg female calf that was morphologically normal but hypertonic and hyperreflexic. Pregnancy had proceeded uneventfully and lasted 9 months and 4 days. Spontaneous reflexes such as sucking, swallowing, micturition, defecation, and crying were completely preserved, but the calf was unable to stand, and its consciousness alternated from mild to severe depression. It was obviously blind and showed ventrolateral strabismus, but the pupils functioned normally. Muscle tone was permanently increased, as indicated by tetanus-like erection of the ears and by a violent but brief startle response to the slightest acoustic or tactile stimulation. When the calf was placed upright, loss of conscious proprioception was obvious; it maintained its position only a few seconds before collapsing. Altogether, the clinical signs suggested severe dysfunctions of the cerebral cortex, basal ganglia, and mesencephalon. The calf drank from a bottle twice a day for a week, but then was euthanized for humane reasons (infected decubital ulcers).

However, the cerebral hemispheres were replaced by 2 thin-walled, fluid-filled cysts with some floating islets and peninsulae corresponding to preserved cortex. There was variable preservation of the cerebrum, total liquefaction of occipital lobes, and irregular preservation of the outer layers of some parts of the temporal and frontal lobes. Altogether, the picture was compatible with severe porencephaly or hydranencephaly. The spine showed no sign of scoliosis, and movement of the limb joints was not restricted (i.e., no arthrogryposis). Samples were removed from the remnants of the cerebrum, diencephalon, and organs (thymus, lung, myocardium, jejunum, ileum, mesenteric lymph node, liver, spleen, kidney, and striated muscle), and 3 independent real-time PCR protocols were conducted to detect genomes of bovine viral diarrhea/mucosal disease virus, bluetongue virus serotype 8, and the novel SBV. Initial retrotranscription of the RNA genomes was followed by quantitative (real-time) PCR. The process was conducted by using our procedures and, for SBV, by following the protocol and using recently developed control reagents as described. The SBV genome was detected in only CNS samples (quantification cycle value 28.8); bovine viral diarrhea/mucosal disease virus and BTV-8 genomes were not detected. The new virus genome load was 1.61 × 104 copies per gram of cerebrum sample.

Emerging Infectious Diseases
May 1, 2012

Original web page at Emerging Infectious Diseases

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DNA traces cattle back to a small herd domesticated around 10,500 years ago

All cattle are descended from as few as 80 animals that were domesticated from wild ox in the Near East some 10,500 years ago, according to a new genetic study. An international team of scientists from the CNRS and National Museum of Natural History in France, the University of Mainz in Germany, and UCL in the UK were able to conduct the study by first extracting DNA from the bones of domestic cattle excavated in Iranian archaeological sites. These sites date to not long after the invention of farming and are in the region where cattle were first domesticated. The team examined how small differences in the DNA sequences of those ancient cattle, as well as cattle living today, could have arisen given different population histories. Using computer simulations they found that the DNA differences could only have arisen if a small number of animals, approximately 80, were domesticated from wild ox (aurochs). The study is published in the current issue of the journal Molecular Biology and Evolution.

Dr Ruth Bollongino of CNRS, France, and the University of Mainz, Germany; lead author of the study, said: “Getting reliable DNA sequences from remains found in cold environments is routine. “That is why mammoths were one of the first extinct species to have their DNA read. But getting reliable DNA from bones found in hot regions is much more difficult because temperature is so critical for DNA survival. This meant we had to be extremely careful that we did not end up reading contaminating DNA sequences from living, or only recently dead cattle.” The number of animals domesticated has important implications for the archaeological study of domestication. Prof Mark Thomas, geneticist and an author of the study based at the UCL Research Department of Genetics, Evolution and Environment: “This is a surprisingly small number of cattle. We know from archaeological remains that the wild ancestors of modern-day cattle, known as aurochs, were common throughout Asia and Europe, so there would have been plenty of opportunities to capture and domesticate them.” Prof Joachim Burger, an author of the study based at the University of Mainz, Germany, said: “Wild aurochs are very different beasts from modern domestic cattle. “They were much bigger than modern cattle, and wouldn’t have had the domestic traits we see today, such as docility. So capturing these animals in the first place would not have been easy, and even if some people did manage snare them alive, their continued management and breeding would still have presented considerable challenges until they had been bred for smaller size and more docile behavior.”

Archaeological studies on the number and size of prehistoric animal bone have shown that not only cattle, but also goats, sheep and pigs were all first domesticated in the Near East. But saying how many animals were domesticated for any of those species is a much harder question to answer. Classical techniques in archaeology cannot give us the whole picture, but genetics can help — especially if some of the genetic data comes from early domestic animals. Dr Jean-Denis Vigne, a CNRS bio-archaeologist and author on the study, said: “In this study genetic analysis allowed us to answer questions that — until now -archaeologists would not even attempt to address. “A small number of cattle progenitors is consistent with the restricted area for which archaeologists have evidence for early cattle domestication ca. 10,500 years ago. This restricted area could be explained by the fact that cattle breeding, contrary to, for example, goat herding, would have been very difficult for mobile societies, and that only some of them were actually sedentary at that time in the Near East.” Dr Marjan Mashkour, a CNRS Archaeologist working in the Middle East added: “This study highlights how important it can be to consider archaeological remains from less well-studied regions, such as Iran. Without our Iranian data it would have been very difficult to draw our conclusions, even though they concern cattle at a global scale.”

Science Daily
May 1, 2012

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