Insecticide treatment of cattle to kill sand flies and combat leishmaniasis

With an estimated 500,000 human infections and 50,000 deaths annually, visceral leishmaniasis (VL) is the second most prevalent parasitic killer, behind malaria. Leishmania parasites are transmitted through the bite of phlebotomine sand flies. A study published in PLOS Neglected Tropical Diseases makes the case that fighting the insects by treating cattle with the long-lasting insecticide, fipronil, could substantially reduce VL in areas where people and cattle live in close proximity.

Two-thirds of VL cases occur on the Indian subcontinent, and 90% of the Indian VL cases are reported in the densely populated and impoverished state of Bihar. Female sand flies there primarily bite humans and cattle (mostly at night), and after sand fly eggs hatch, the larvae feed on organic matter, the most abundant source being cow patties. At present, control of sand flies in India involves indoor residual spraying with pyrethroid insecticides, but Bihari villagers regularly sleep outdoors during the hot summer months.

Fipronil is an insecticide with a long half-life. The insecticide remains in the system of animals for several weeks to several months, dependent on the concentration administered. Fipronil does not harm mammals at low concentrations, but when fed to cattle at low concentrations in drug form, can kill adult blood-feeding sand flies and sand fly larvae that feed on the cattle feces. Fipronil-based sand fly control could therefore last for several months following a single treatment — and complement the practice of indoor spraying.

David Poché, from Texas A&M University in College Station, USA, and colleagues set out to explore the insecticide’s potential to control sand flies. The researchers developed a mathematical model that describes the effects of fipronil-induced mortality on a sand fly population within a village in Bihar. They describe the model and evaluate its performance based on known parameters. Then they use the model to simulate fipronil-based control schemes with different treatment timing and frequency, and compare their effect on reductions in sand fly populations during spring and summer (June, July, and August are the period of peak human exposure).

Single annual treatments applied in March, May, June, or July noticeably reduced the population peaks that occurred over the 30 to 60 days following treatment, but populations recovered relatively quickly. Treatments applied 3 times per year at 2-month intervals were most effective when initiated in March, reducing the population peaks in April through August by roughly 90% relative compared with no treatment. Treatments applied 6 times per year at 2-month intervals were most effective when initiated in January, reducing population peaks in June through August by over 95%. Monthly treatments resulted in eradication of the sand fly population within 2 years.

Overall, the simulation results suggest that the success of fipronil treatment depends not only on the frequency of applications but also on the timing relative to the sand fly lifecycle. Maintaining high drug levels in cattle feces during the period of high larval abundance seems particularly important.

As the researchers discuss, “while more frequent applications obviously are more efficacious, they also are more expensive and more difficult logistically. Thus, the ability to assess not only efficacy of treatment schemes per se but also their cost-effectiveness and their logistical feasibility is of paramount importance.” In this context, they mention an estimated cost of $1 per cow per treatment, as well as the fact that milk production per cow is estimated to increase by $0.50 per day, thus offering an incentive to villagers to treat their animals.

Further evaluation of sand fly control through the use of fipronil-based drugs in cattle, the researchers say, ideally would involve a field trial in Bihar. Such a trial could provide data on the actual proportion of adult sand flies that obtain their blood meal from cattle and the proportion of eggs laid in organic matter containing cattle feces; numbers that are currently unknown and therefore force the researchers to make assumptions that cause uncertainty in the model predictions.

Suggesting that their model could be adapted to settings where donkeys, dogs, rabbits, or rodents are the main animal targets of blood-thirsty sand flies, the researchers hope that it “will prove useful in the a priori evaluation of the potential role of treatment schemes involving the use of fipronil-based drugs in the control of leishmaniasis on the Indian Subcontinent and beyond.”  Science Daily  Original web page at Science


* Happy cows make more nutritious milk

Daily infusions with a chemical commonly associated with feelings of happiness were shown to increase calcium levels in the blood of Holstein cows and the milk of Jersey cows that had just given birth. The results, published in the Journal of Endocrinology, could lead to a better understanding of how to improve the health of dairy cows, and keep the milk flowing.

Demand is high for milk rich in calcium: there is more calcium in the human body than any other mineral, and in the West dairy products such as milk, cheese and yoghurt are primary sources of calcium. But this demand can take its toll on milk-producing cows: roughly 5-10% of the North American dairy cow population suffers from hypocalcaemia — in which calcium levels are low. The risk of this disease is particularly high immediately before and after cows give birth.

Hypocalcaemia is considered a major health event in the life of a cow. It is associated with immunological and digestive problems, decreased pregnancy rates and longer intervals between pregnancies. These all pose a problem for dairy farmers, whose profitability depends upon regular pregnancies and a high-yield of calcium-rich milk.

Whilst there has been research into the treatment of hypocalcaemia, little research has focused on prevention. In rodents it has been shown that serotonin (a naturally-occurring chemical commonly associated with feelings of happiness) plays a role in maintaining calcium levels; based on this, a team from the University of Wisconsin-Madison, led by Dr Laura Hernandez, investigated the potential for serotonin to increase calcium levels in both the milk and blood of dairy cows. The team infused a chemical that converts to serotonin into 24 dairy cows, in the run up to giving birth. Half the cows were Jersey and half were Holstein — two of the most common breeds. Calcium levels in both the milk and circulating blood were measured throughout the experiment.

Whilst serotonin improved the overall calcium status in both breeds, this was brought about in opposite ways. Treated Holstein cows had higher levels of calcium in their blood, but lower calcium in their milk (compared to controls). The reverse was true in treated Jersey cows and the higher milk calcium levels were particularly obvious in Jerseys at day 30 of lactation — suggesting a role for serotonin in maintaining levels throughout lactation.

“By studying two breeds we were able to see that regulation of calcium levels is different between the two,” says Laura Hernandez. “Serotonin raised blood calcium in the Holsteins, and milk calcium in the Jerseys. We should also note that serotonin treatment had no effect on milk yield, feed intake or on levels of hormones required for lactation.”

The next steps are to investigate the molecular mechanism by which serotonin regulates calcium levels, and how this varies between breeds.

“We would also like to work on the possibility of using serotonin as a preventative measure for hypocalcaemia in dairy cows,” continues Laura Hernandez, “That would allow dairy farmers to maintain the profitability of their businesses, whilst making sure their cows stay healthy and produce nutritious milk.”  Science Daily Original web page at Science Daily


* Two thirds of cattle attacks on people involve dogs, new study finds

Dog owners are being urged to remember to be vigilant with their pets when walking near cows in the countryside, following a new review into cattle attacks by the University of Liverpool.

Anecdotal media and hospital reports of cattle causing injury or death to members of the public have existed for many years, but until now no further investigation has been carried out examining why these events may occur.

This project reviewed details of negative interactions between the public and cattle, to identify risk factors for cattle attacks, and highlight the availability and usefulness of guidance on walking among livestock.

A total of 54 cattle attacks were reported in the UK media between 1993 and 2013 and, of these, approximately one in four were fatal and two-thirds involved dogs.

Dr Carri Westgarth, a dog behaviour expert at the University’s Institute of Infection and Global Health, said: “We found that walking with dogs among cows, particularly with calves present, was a common factor for an attack.

“One theory for this is that the cows may feel particularly threatened by dogs, especially if they have young to protect. People then try to protect their dogs, which can lead to a tragic incident occurring.”

The review of published literature, newspaper articles and web pages also highlighted that injuries from cattle are a significant and under-reported public health risk.

Dr Marie McIntyre, who co-authored the review, said: “There is currently no official system in place for reporting attacks, so it is highly likely that there have been far more incidents than we know about. Further work is needed to fully assess the public health impact of this issue.”

There are approximately 300,000 farms and 9.7 million cattle in the UK. Many public rights of way cross farmland, so while walking people come into contact with livestock, particularly cattle.

Within the various guidelines reviewed, advice of how to behave around cattle and avoid injury were found to vary, in particular concerning control of dogs.

Dr Westgarth added: “The countryside is a great place to exercise dogs, but it’s every owner’s duty to make sure that their dog is not a danger or nuisance to farm animals, wildlife or other people. Considering our findings, the best advice, if cattle approach, would be to let your dog off the lead, as then it can escape, and the cows are also likely to remove their focus from you.”  Science Daily  Original web page at Science Daily


Detection of influenza D virus among swine and cattle, Italy

Recent studies have identified a new genus of the Orthomyxoviridae family. The virus, distantly related to human influenza C virus, has been provisionally designated as influenza D virus. This novel virus was identified for the first time in pigs with influenza-like illness, but subsequent serologic and virologic surveys have suggested cattle as a possible reservoir. Moreover, the virus was shown to infect ferrets used in laboratories as surrogates for humans when investigating influenza infection. In a serologic study conducted on 316 human samples, low antibody titers and a low level of positive samples were detected, suggesting that humans are a possible host to be studied in depth. To investigate the circulation of influenza D viruses among pigs and cattle in Italy, we performed biomolecular and virological tests on clinical samples collected from respiratory outbreaks in Po Valley, the area in Italy with the highest density of swine and cattle farms.

Clinical specimens were screened from swine (n = 150) and cattle (n = 150) for influenza D virus by reverse transcription quantitative PCR. Three nasal swab samples were found positive: 1 from a sow and 2 from cattle, collected from 3 farms located at linear distances ranging from 47 to 80 km. All positive samples were confirmed by partial polymerase basic 1 gene sequencing and submitted to viral isolation in cell cultures as previously described. The virus was isolated on CACO-2 and HRT18 cell cultures only from the sow sample. Cell cultures were tested by using reverse transcription quantitative PCR. Viral RNA was isolated from clinical samples or cell culture by using One-For-All Vet Kit (QIAGEN, Milan, Italy). Full-genome amplification from influenza D virus–positive samples was achieved as previously described. A sequencing library of the purified amplicons was prepared by using NEXTERA-XT kit and sequenced by using a Miseq Reagent Kit v2 in a 250-cycle paired-end run (both from Illumina Inc., San Diego, CA, USA). Sequencing reads were assembled de novo or by using D/swine/Oklahoma/1334/2011 (GenBank accession nos. JQ922305–JQ922311) as a template by Seqman NGen DNASTAR version 11.2.1 (DNASTAR, Madison, WI, USA). Gene sequences from the 3 influenza D viruses isolated in Italy and all the available influenza D virus sequences retrieved from GenBank were aligned with ClustalW by using MEGA5. We analyzed the predicted amino acid sequences for each gene.  Emerging Infectious Diseases  Original web page at Emerging Infectious Diseases


Extinct 3-horned palaeomerycid ruminant found in Spain

The extinct three-horned palaeomerycid ruminant, Xenokeryx amidalae, found in Spain, may be from the same clade as giraffes, according to a study published December 2, 2015 in the open-access journal PLOS ONE by Israel M. Sánchez from the Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain, and colleagues.

Palaeomerycids, now extinct, were strange three-horned Eurasian Miocene ruminants known through fossils from Spain to China. In this article, the authors classify the palaeomerycid to their clade based on shared characteristics with the best-known species of the group and reassess their phylogenetic position among ruminants, which is currently disputed. The authors use well-preserved remains of a new palaeomerycid, Xenokeryx amidalae, which included a complete sample of cranial–including both frontal and supra-occipital ‘t-shaped’ cranial appendages–dental, and postcranial remains, from middle Miocene deposits of Spain.

The authors found that despite their apparent external similarities, Eurasian palaeomerycids are not closely related to North American dromomerycids, distant relatives to deer, as some scientists have thought. Instead, palaeomerycids are in the clade Giraffomorpha, the least inclusive clade containing Giraffa and Triceromeryx. The authors conclude that future ruminant research will benefit from more in-depth analysis, such as phylogenetic analysis combining fossil and living taxa, morphological and molecular datasets, and fossil ages.

Israel Sánchez adds: “Establishing the place of palaeomerycids in the ruminant tree gives us insights into the evolutionary history of the large clade of pecoran ruminants that include giraffes (Giraffa and Okapia) as its only extant survivors, and shows us the amazing diversity of an ancient lineage that inhabited both Eurasia and Africa.”  Science Daily  Original web page at Science Daily


* Intensive farming link to bovine TB

Intensive farming practices such as larger herd size, maize growth, fewer hedgerows and the use of silage have been linked to higher risk of bovine TB, new research has concluded.

A study by the University of Exeter, funded by BBSRC and published in the Royal Society journal Biological Letters, analysed data from 503 farms which have suffered a TB breakdown alongside 808 control farms in areas of high TB risk.

Dr Fiona Mathews, Associate Professor in Mammalian Biology, who led the study, said: “TB is absolutely devastating for farming, and it’s essential that workable solutions are found. In the worst hit areas, farms are frequently affected over and over again with crippling consequences. If lower intensity production means better animal health, it offers a sustainable long-term strategy in high risk areas.”

The last few decades have seen radical changes in farming practices. Half of British dairy farmers have gone out of business since 2002. Those that remain have larger herds and greater productivity: average herd size increased from 75 animals in 1996 to 133 in 2014 (a rise of 77%), and the annual yield increased from 5,775 per cow in 1995 to 7,535l per cow in 2013 (a rise of 27%).

The team found that farms with herds of 150 cattle or more were 50% more likely to suffer a bovine TB outbreak than those with herds of 50 or fewer. Patterns of crop production and feeding were also important, with the risks increasing with practices linked with higher productivity systems. For every 10 hectares of maize — a favourite food of the badgers that play a role in transmitting the disease — bTB risk increased by 20%. The feeding of silage was linked with a doubling of the risk in both dairy and beef systems. Landscape features such as deciduous woodland, marshes and hedgerows were also important. For example, on farms with 50km of field boundaries, each extra 1km of hedgerow was linked with a 37% reduction in risk. This is likely to be because there is less contamination of pasture by badger faeces and urine in hedgerow-rich areas. Marshland was associated with increased risk, possibly as a secondary effect of infection with liver fluke — a disease linked with wet environments and which interferes with the diagnosis of bTB in cattle.

Dr Mathews said: “To beat TB, we need to ensure our approach is robust and evidence-based. This is the first large-scale study to link a range of landscape-scale habitat features and farming practices with bTB. All of the effects we have found are additive, so changing several linked aspects of the farming system could potentially make a big difference. Farmers are already aware that biosecurity in the farmyard can help reduce the risk of bTB in cattle. We have now shown that wider environmental management is also important. By finding out more about these links, we hope that we can help eradicate this terrible disease.”

The paper, ‘Environmental Risk Factors Association with Bovine Tuberculosis in Cattle high Risk Areas’, is published online in the journal Biological Letters today.  Science Daily  Original web page at Science Daily


* Ancient wild ox genome reveals complex cow ancestry

The ancestry of domesticated cattle proves more complex than previously thought, reports a paper published in the open access journal Genome Biology. The first nuclear genome sequence from an ancient wild ox reveals that some modern domestic cow breeds, including the Scottish Highland and Irish Kerry, had wild ancestors that were British, as well as Asian.

The aurochs, Bos primigenius, is an extinct wild ox species that ranged across the grasslands of Eurasia and North Africa 11,000 years ago. Domestication of aurochs gave rise to two major groups of cattle; Bos taurus and Bos indicus.

Previous studies have shown that European B. taurus are descended from western Asian populations of aurochs. However, little was known about the relationship between domesticated cattle and wild aurochs in Europe, and how wild populations contributed to the evolutionary history of the cows that graze our fields today.

To build a clearer picture of the ancestry of European cattle breeds, scientists from University College Dublin extracted genetic material from a bone of a 6,750 year old wild British aurochs discovered in a cave in Derbyshire, England. They then sequenced its complete genome — its genetic blueprint — and compared it with the genomes of 81 domesticated B. taurus and B. indicus animals, and DNA marker information from more than 1,200 modern cows.

The team of researchers discovered clear evidence of breeding between wild British aurochs and early domesticated cattle. David MacHugh, senior author on the study from the School of Agriculture and Food Science at University College Dublin, said: “Our results show the ancestors of modern British and Irish breeds share more genetic similarities with this ancient specimen than other European cattle. This suggests that early British farmers may have restocked their domesticated herds with wild aurochs.”

Genes linked to neurobiology and muscle development were also found to be associated with domestication of the ancestors of European cattle, indicating that a key part of the domestication process was the selection of cattle based on behavioural and meat traits.

David MacHugh added: “This is the first complete nuclear genome sequence from the extinct Eurasian aurochs. Our new study contradicts earlier simple models of cattle domestication and evolution that we and others proposed based on mitochondrial DNA or Y chromosomes. What now emerges from high-resolution studies of the nuclear genome is a more nuanced picture of crossbreeding and gene flow between domestic cattle and wild aurochs as early European farmers moved into new habitats such as Britain during the Neolithic.” Science Daily  Original web page at Science Daily


Cancer-fighting viruses win approval

US regulators clear a viral melanoma therapy, paving the way for a promising field with a chequered past. An engineered herpesvirus that provokes an immune response against cancer has become the first treatment of its kind to be approved for use in the United States, paving the way for a long-awaited class of therapies. On 27 October, the US Food and Drug Administration (FDA) approved a genetically engineered virus called talimogene laherparepvec (T-VEC) to treat advanced melanoma. Four days earlier, advisers to the European Medicines Agency had endorsed the drug.

With dozens of ongoing clinical trials of similar ‘oncolytic’ viruses, researchers hope that the approval will generate the enthusiasm and cash needed to spur further development of the approach. “The era of the oncolytic virus is probably here,” says Stephen Russell, a cancer researcher and haematologist at the Mayo Clinic in Rochester, Minnesota. “I expect to see a great deal happening over the next few years.”

Many viruses preferentially infect cancer cells. Malignancy can suppress normal antiviral responses, and sometimes the mutations that drive tumour growth also make cells more susceptible to infection. Viral infection can thus ravage a tumour while leaving abutting healthy cells untouched, says Brad Thompson, president of the pharmaceutical-development firm Oncolytics Biotech in Calgary, Canada.

The strategy builds on a phenomenon that has been appreciated for more than a century. Physicians in the 1800s noted that their cancer patients sometimes unexpectedly went into remission after experiencing a viral infection. These case reports later inspired doctors, particularly in the 1950s and 1960s, to raid nature’s viral cupboard. Clinicians injected cancer patients with a menagerie of viruses. Sometimes the therapy destroyed the tumour, and sometimes it killed the person instead.

Unlike the wild viruses used in those mid-twentieth-century experiments, some of today’s anti-cancer viruses are painstakingly engineered. T-VEC, for example, has been altered to drastically reduce its ability to cause herpes. Researchers also inserted a gene encoding a protein that stimulates the immune system, which makes the virus even more potent against cancer.

As more researchers entered the field and initiated small clinical tests, they began to produce enticing anecdotes. Russell recalls the case of an individual with myeloma who remained sick after under­going two stem-cell transplants. A tumour on the left side of her forehead had degraded the bone underneath and was putting pressure on her brain. Yet treatment with an experimental virus sent her into complete remission (S. Russell et al. Mayo Clin. Proc. 89, 926–933; 2014). “She’s a star patient who convinced us that this oncolytic paradigm can really work,” he says.

But statistics — not anecdotes — rule over drug approvals. In 2005, regulators in China approved an oncolytic adenovirus called H101 to treat head-and-neck cancer, after evidence showed that the treatment could shrink tumours. Those trials stopped short of assessing improvements in patient survival — a measure often required for FDA approval. Since then, a medical-tourism industry has built up in China for people who cannot get the therapy in their home countries.

Then, in May this year, a team supported by biotechnology giant Amgen of Thousand Oaks, California, published promising results from a large clinical trial of T-VEC (R. H. Andtbacka et al. J. Clin. Oncol. 33, 2780–2788; 2015). The virus both shrank tumours in people with advanced melanoma and extended patient survival by a median of 4.4 months. Yet statistically, survival benefits fell just a hair’s breadth of significance. “That raised the question, ‘Well, what is statistical significance? Is this an active agent or not?’” Russell says.

He and others note that the therapy — which must be injected directly into tumours — seemed to rein in cancer elsewhere in the body as well. This is a sign that results are real and that the virus sparked an immune response as intended, Thompson says.

Administering T-VEC in combination with cancer immunotherapy could prove particularly effective, notes Stephen Hodi, an oncologist at the Dana-Farber Cancer Institute in Boston, Massachusetts. In June 2014, a small clinical trial by Amgen suggested that this combination may boost effectiveness over that of the immunotherapies alone.

And researchers continue to look for ways to improve T-VEC. In particular, they would like to be able to deliver the therapy systemically, so that the virus could target tumours in organs that are difficult to reach with an injection. This would require a technique to prevent the body from mounting an immune response to the virus prematurely, which would disable it before it could reach and kill tumour cells, says Howard Kaufman, a cancer researcher at Rutgers Cancer Institute of New Jersey.

To that end, those in the field are experimenting with a smorgasbord of viruses — from poxviruses to vesicular stomatitis virus, which does not normally infect humans but causes a blistering disease in cattle. Oncolytics Biotech is studying a virus that hitch-hikes through the body on certain blood cells, camouflaged from the immune system.

If cancer-killing viruses could be delivered to their targets through the bloodstream, rather than via injection directly into the tumour, they could be used to treat a greater range of cancers. Thompson envisions a day when physicians will be able to peruse a menu of oncolytic viruses and select the best fit. “Each virus interacts with the immune system differently,” he says. “They could have a role in pretty much all cancer therapy.”

Nature 526, 622–623 (29 October 2015) doi:10.1038/526622a  Nature  Original web page at Nature


* Virus in cattle linked to human breast cancer

A new study by University of California, Berkeley, researchers establishes for the first time a link between infection with the bovine leukemia virus and human breast cancer. In the study, published this month in the journal PLOS ONE and available online, researchers analyzed breast tissue from 239 women, comparing samples from women who had breast cancer with women who had no history of the disease for the presence of bovine leukemia virus (BLV). They found that 59 percent of breast cancer samples had evidence of exposure to BLV, as determined by the presence of viral DNA. By contrast, 29 percent of the tissue samples from women who never had breast cancer showed exposure to BLV.

“The association between BLV infection and breast cancer was surprising to many previous reviewers of the study, but it’s important to note that our results do not prove that the virus causes cancer,” said study lead author Gertrude Buehring, a professor of virology in the Division of Infectious Diseases and Vaccinology at UC Berkeley’s School of Public Health. “However, this is the most important first step. We still need to confirm that the infection with the virus happened before, not after, breast cancer developed, and if so, how.”

Bovine leukemia virus infects dairy and beef cattle’s blood cells and mammary tissue. The retrovirus is easily transmitted among cattle primarily through infected blood and milk, but it only causes disease in fewer than 5 percent of infected animals.

A 2007 U.S. Department of Agriculture survey of bulk milk tanks found that 100 percent of dairy operations with large herds of 500 or more cows tested positive for BLV antibodies. This may not be surprising since milk from one infected cow is mixed in with others. Even dairy operations with small herds of fewer than 100 cows tested positive for BLV 83 percent of the time.

What had been unclear until recently is whether the virus could be found in humans, something that was confirmed in a study led by Buehring and published last year in Emerging Infectious Diseases. That paper overturned a long-held belief that the virus could not be transmitted to humans.

“Studies done in the 1970s failed to detect evidence of human infection with BLV,” said Buehring. “The tests we have now are more sensitive, but it was still hard to overturn the established dogma that BLV was not transmissible to humans. As a result, there has been little incentive for the cattle industry to set up procedures to contain the spread of the virus.

The new paper takes the earlier findings a step further by showing a higher likelihood of the presence of BLV in breast cancer tissue. When the data was analyzed statistically, the odds of having breast cancer if BLV were present was 3.1 times greater than if BLV was absent.

“This odds ratio is higher than any of the frequently publicized risk factors for breast cancer, such as obesity, alcohol consumption and use of post-menopausal hormones,” said Buehring.

There is precedence for viral origins of cancer. Hepatitis B virus is known to cause liver cancer, and the human papillomavirus can lead to cervical and anal cancers. Notably, vaccines have been developed for both those viruses and are routinely used to prevent the cancers associated with them.

“If BLV were proven to be a cause of breast cancer, it could change the way we currently look at breast cancer control,” said Buehring. “It could shift the emphasis to prevention of breast cancer, rather than trying to cure or control it after it has already occurred.”

Buehring emphasized that this study does not identify how the virus infected the breast tissue samples in their study. The virus could have come through the consumption of unpasteurized milk or undercooked meat, or it could have been transmitted by other humans.  Science Daily  Original web page at Science Daily


Cattle disease spread by vets, not cows

A cattle disease that affected more than 5,000 cows, over 500 of which were killed, was probably spread by vets farmers and cattle traders in Germany, according to one of the first research articles published in the new open access journal Heliyon. The authors of the study, from Friedrich-Loeffler-Institute (FLI), Germany, say farmers and people who visit farms should take biosecurity measures like wearing disposable clothes where there is a risk of infection.

One of the most important infectious diseases in cattle, Bovine Viral Diarrhea (BVD) leads to severe disease and significant economic losses globally. Caused by the Bovine Viral Diarrhea Virus (BVDV), BVD suppresses the immune system and causes a variety of symptoms, including respiratory problems, infertility, and abortion.

Because of its biological and economic significance, an attempt has been made to eradicate BVD in Germany. This has in some farms resulted in a cattle population that has neither been exposed to the virus nor vaccinated, making it more susceptible to infection.

In 2012 a highly virulent type of BVDV virus (BVDV-2c) was introduced into a cattle farm in Germany and transmitted to other farms. This led to several outbreaks and a high number of deaths among the 5,325 affected cattle on 21 farms. “A dairy farmer first noticed a reduction in milk yield, respiratory symptoms, nasal discharge, fever, sporadic diarrhea and sudden deaths — these symptoms were also noted on other farms as the infection spread, but did not immediately indicate BVD as the cause,” said Dr. Jörn Gethmann, lead author of the study from Friedrich-Loeffler-Institute. “We were surprised by the high morbidity and mortality an induced by a BVDV strain in this outbreak.”

The researchers supported the competent local authorities in tracing the spread of the virus. They visited eight farms and obtained data on a further 13 farms. They discovered that the virus was not transmitted directly by infected cattle, but mostly by people such as vets and traders who were moving between farms. “We were surprised to see the effective transmission to other farms without persistently infected animals involved,” commented Dr. Gethmann.

Lab analyses revealed the source of the outbreak was a BVD type 2c virus that has a particular addition to its genome. The virus appears to be associated with more severe symptoms than BVD; the fatality rate was up to 60% and between 2.3% and 29.5% of the cattle on each farm died during the outbreak.

Once the cause was identified, swift measures were taken to control the outbreak. Veterinary authorities imposed trade restrictions on affected farms. People who had been in contact with infected cattle were generally advised to increase biosecurity measures, for example by wearing disposable clothing. On some farms, affected animals were vaccinated against BVD to reduce clinical signs as an ’emergency measure’.

This approach stopped the further spread of the disease. However, the researchers say it is important to revisit control programs regularly and adapt them to the changing situation, for example with new virulent strains arising.

“The results of our study may help to revise existing BVD control regulations and increase biosecurity in cattle farms, in particular by reducing the risk of disease transmission through person contacts and trade,” said Dr. Gethmann. “We also hope our study will inform farmers about the risks of the introduction of new BVD types into their farms.”  Science Daily  Original web page at Science Daily


Whale microbiome shares characteristics with both ruminants, predators

To some, it may not come as a surprise to learn that the great whales are carnivores, feeding on tiny shrimp-like animals such as krill. Moreover, it might not be surprising to find that the microbes that live in whale guts -the so-called microbiome- resemble those of other meat eaters. But scientists now have evidence that the whales’ microbiome shares traits with creatures not known to eat meat — cows.

Led by Peter Girguis, Professor of Organismic and Evolutionary Biology, scientists have found that the gut microbiome of right whales and other baleen species shares characteristics with both cows and meat-eating predators. The dual microbial communities allow whales to extract the most nutrition possible from their diet, digesting not only the copepods they eat, but their chitin-rich shells as well. The study is described in a September 22 paper in Nature Communications.

“From one point of view, whales look like carnivores,” Girguis said. “They have the same kind of microbes that we find in lions and tigers that have very meat-rich diets. But they also have abundant communities of anaerobic bacteria, similar to those that ruminants use to break down cellulose.

“However, there’s not a lot of cellulose in the ocean, but there is a lot of chitin, which is in the exoskeletons of copepods that baleen whales eat,” Girguis continued. “What our paper suggests is the whale foregut is much like a cow’s gut, and we posit that chitin-degrading anaerobic microbial community thrives in there, breaking down that material and making it available to the whale.”

Those exoskeletons, Girguis said, represent as much as ten percent of whale’s total food intake, and would otherwise simply be defecated. By allowing whales to access the nutrition in the chitin-rich material, whales are able to extract the most possible benefit from their diet.

“It’s almost like a pre-adaptation,” he said “that may give them a differential advantage in harnessing energy from their food. The morphology of their gut comes from their ancestors, the very same ancestors to cows, camels and other ruminants. It serves them well even as carnivores because it allows them to maximally extract nutrition from their food.”

Ultimately, Girguis said, the study addresses questions that reach far beyond the guts of whales. “This is really a question of what we can call phylogenetic inertia,” he said. “Because what we’re really thinking about is: When you look at the microbiome of an organism, you can -to some degree- look back in time and see its ancestors, because organisms that are related to one another seem to have similar microbiomes.

“But not all organisms that are related live in the same kind of environment,” he continued. “So the question is how different does your environment need to be before it changes your microbiome? This is a fundamental question about the relationship between your ancestry versus your current environment.” Many of those questions, however, might not have been asked, Girguis said, were it not for then-undergraduate student Annabel Beichman.

Now a graduate student at UCLA and the second author of the study, Beichman kick-started the study when she and University of Vermont conservation biologist Joe Roman took on the unenviable task of following pods of right whales at sea and collecting samples of their feces to determine which microbes were present. “There’s no other way to get the fecal samples but to collect them from the ocean,” Roman said.

“It was a thrill to set out each morning into uncertain weather to search for elusive right whales, then to extract and sequence DNA from our smelly trophies,” Beichman said. “It had always been my passion to use the latest advances in genetic sequencing technology to answer questions about species of conservation concern, and so I wanted to add a genetic component to the study.

“Working with my advisors to conceive the research questions based on the scientific literature, collect fecal samples in the field, and carry out DNA sequencing and analysis gave me invaluable experience at every stage of the study,” she added. “We all had different theories as to what the whale gut community might look like. What none of us expected was to see so much divergence from terrestrial mammals, or these shared characteristics with both terrestrial carnivores’ and herbivores’ microbiomes.”

“Given what we know about whales’ ancestry — that they’re related to ruminants, and that they still have a multi-chambered foregut — there were several things we might find,” Girguis said. “One hypothesis was that their microbiome would look like those of other meat-eaters like lions and tigers, and the foregut was just vestigial. The other hypothesis was that it allowed a different group of microbes to do something we hadn’t thought about. What we found was that whales have a microbiome that looks halfway like a ruminant and halfway like a carnivore.

“We’ve come to better understand the evolution of whales over the past few decades, and see where they fit on the evolutionary tree. But we have not understood the microbial changes that have allowed them to become one of the most successful groups of animals in the ocean,” said Roman. “This study helps explain that.”

Going forward, Girguis and colleagues hope to sample the microbial community in whales’ stomach chambers, and to extend the study to toothed whales, which don’t have such chitin-rich diets. The team has also received interest from aquariums, which may be able to use information about the gut microbes in whales in order to better care for animals kept in captivity.

“A lot of aquariums…they know when their whales are healthy or not, but they don’t always have a causal factor, and these gut microbes may be a big clue,” Girguis said. “As long as people keep whales in captivity, there is value in this type of research, because it can keep them as healthy as possible.”

While it may not provide a definitive answer to questions of phylogenetic inertia, the study does suggest that some morphological features, if they can provide an advantage, are retained, despite dramatic changes in a creature’s environment.

“We now have this snapshot that addresses this question of how a creature’s evolutionary past interacts with its microbiome, and how their diet today influences their microbiome,” he said. “The answer is…if that morphological feature, if it has value to a species, then it may well be something that’s capitalized on over evolutionary time.   Science Daily  Original web page at Science Daily


* Novel fatigue syndrome in feedlot cattle discovered

Researchers at Kansas State University’s College of Veterinary Medicine, in collaboration with colleagues at Iowa State University and Texas Tech University, have discovered a novel fatigue syndrome affecting feedlot cattle. The syndrome is similar to one affecting the swine industry.

The researchers’ landmark paper, “Description of a novel fatigue syndrome of finished feedlot cattle following transportation,” appeared as a special report in the July 15 issue of the Journal of the American Veterinary Medical Association.

“This syndrome has been identified in the swine industry and had not been identified in cattle until our work that started in 2013,” Thomson said. “Our landmark paper places an emphasis on cattle stress at the end of the feeding period with items such as heat load, animal size, cattle handling at shipping, time of day of shipping, animal transportation and other issues that could be causing stress of large cattle during the summer time.”

The study was spurred by observations made during summer 2013. Abattoirs throughout the United States reported concerns about slow and difficult-to-move cattle and other mobility problems that developed soon after arrival at the facilities. Affected cattle had various clinical signs, including rapid breathing with an abdominal component to respiration, lameness and reluctance to move. Many of the cattle affected with mobility problems had clinical signs similar to those of pigs with fatigued pig syndrome, a multifactorial condition in which affected pigs become nonambulatory without obvious injury, trauma or disease, and refuse to walk.

“I think this paper is the first publication of the interaction between beta-agonists and lameness issues in cattle,” Ensley said. “The beta-agonists are widely used in cattle and pig feeding and there is very little information about adverse effects. More work needs to be done, but this is a great start.”

Beta-agonists are supplements fed to cattle. Part of the pathophysiology points to a metabolic overload of sorts that result in or from respiratory insufficiency and muscle damage, Loneragan said. “While we don’t know the cause, it appears to be multifactorial in nature, but warrants further investigation,” Loneragan said. “It is important to be able to share case reports like the ones described. While it is not always as thorough as a case report of hospitalized animals, these field-based observations are nevertheless of value and under Dr. Thomson’s leadership, we were able to dig relatively deeply into these events and provide a report to share with our profession.”

Also described in the manuscript is a problematic condition — possibly an extreme endpoint of the fatigued cattle syndrome — where animals sloughed one or more hooves. “Based on microscopic examination, this appears to be a distinct condition and is likely not laminitis resulting from dietary disturbances,” Loneragan said. “It is clear this results in intense pain for the animals. The abattoir companies have decided that events like these are unacceptable, and I applaud their dedication and commitment to protecting the welfare of the animals they depend on for their business and we depend on for food.”

The study concludes it would be imperative for the beef industry and affiliated veterinarians to learn quickly as much as possible about fatigue cattle syndrome so measures can be implemented to prevent the condition, or at least minimize its impact on cattle welfare.  Science Daily  Original web page at   Science Daily


* Feed supplement greatly reduces dairy cow methane emissions

A supplement added to the feed of high-producing dairy cows reduced methane emissions by 30 percent and could have ramifications for global climate change, according to an international team of researchers.

In addition, over the course of the 12-week study conducted at Penn State’s dairy barns, cows that consumed a feed regimen supplemented by the novel methane inhibitor 3-nitrooxypropanol — or 3NOP — gained 80 percent more body weight than cows in a control group. Significantly, feed intake, fiber digestibility and milk production by cows that consumed the supplement did not decrease.

The findings are noteworthy because methane is a potent greenhouse gas. The U.S. Environmental Protection Agency estimates that methane from livestock makes up 25 percent of the total methane emissions in the

United States. Globally, according to the United Nations’ Food and Agriculture Organization, animal agriculture emits 44 percent of the methane produced by human activity. Fermentation in the rumen — one of the four stomach chambers of livestock such as cattle, sheep and goats — generates the methane, as a result of microorganisms that aid in the process of digestion. The animals must expel the gas to survive. The 3NOP supplement blocks an enzyme necessary to catalyze the last step of methane creation by the microbes in the rumen.

It was important to conduct the study under industry-relevant conditions, said lead researcher Alexander Hristov, professor of dairy nutrition. The researchers published their results in a recent issue of the Proceedings of the National Academy of Sciences

“We tested methane-mitigation compounds using animals with similar productivity to those on commercial farms because the nutrient requirements of high-producing dairy cows are much greater than those of nonlactating or low-producing cows,” he explained.

“Any reduction in feed intake caused by a methane-mitigation compound or practice would likely result in decreased productivity — which may not be evident in low- producing cows.”

Methane expulsion through burping represents a net loss of feed energy for livestock, Hristov noted, adding that a high-producing dairy cow typically emits 450 to 550 grams per day of ruminal gas produced by fermentation. The spared methane energy was used partially for tissue synthesis, which led to a greater body weight gain by the inhibitor-treated cows.

The 48 Holsteins in the study received varying amounts of the inhibitor in their feed and were observed at regular daily intervals over three months. Their methane emissions were measured when the cows put their heads into feeding chambers that had atmospheric measurement sensors, and also through nostril tubes attached to canisters on their backs.

In recent years animal scientists have tested a number of chemical compounds to inhibit methane production in ruminants, and one even achieved a 60 percent reduction, Hristov said. However, the viability of that and other compounds as mitigation agents has been discounted due to concerns about animal health, food safety or environmental impact

The 3NOP compound, developed by DSM Nutritional Products, a Dutch company that is one of the world’s leading suppliers of feed additives, seems to be safe and effective, Hristov said.

If approved by the U.S. Food and Drug Administration and adopted by the agricultural industry, this methane inhibitor could have a significant impact on greenhouse gas emissions from the livestock sector, Hristov suggested. But producers will have to have an incentive to use the feed additive.

“It is going to cost money for dairy producers to put this into practice, and if they don’t see a benefit from it, they are not going to do it,” he said.

“The thing that is critical is body gain — dairy cows go through phases, and they lose a lot of weight when they calf. They don’t eat enough, and they produce a lot of milk and lose weight, so if we can cut down the energy loss with the inhibitor, the animals will gain more body weight and recover more quickly. Further, they may produce more milk in early lactation and have improved reproduction. It’s something that will convince producers to use it.  Science Daily  Original web page at Science Daily


* Environmental exposure to hormones used in animal agriculture greater than expected

Research by an Indiana University environmental scientist and colleagues at universities in Iowa and Washington finds that potentially harmful growth-promoting hormones used in beef production are expected to persist in the environment at higher concentrations and for longer durations than previously thought. “What we release into the environment is just the starting point for a complex series of chemical reactions that can occur, sometimes with unintended consequences,” said Adam Ward, lead author of the study and assistant professor in the IU Bloomington School of Public and Environmental Affairs. “When compounds react in a way we don’t anticipate — when they convert between species, when they persist after we thought they were gone — this challenges our regulatory system.”

Numerical simulations performed in this study can help to predict the potential impact of environmental processes on contaminant fate to more effectively understand the potential for these unexpected effects. This study illustrates potential weaknesses in the U.S. system of regulating hazardous substances, which focuses on individual compounds and often fails to account for complex and sometimes surprising chemical reactions that occur in the environment. The publication, “Coupled reversion and stream-hyporheic exchange processes increase environmental persistence of trenbolone metabolites,” was published by Nature Communications and is now available online.

The study focuses on the environmental fate of trenbolone acetate, or TBA, a highly potent synthetic analogue of testosterone, used to promote weight gain in beef cattle. A majority of beef cattle produced in the U.S. are treated with TBA or one of five other growth hormones approved for use in animal agriculture. The compound and its byproducts are examples of contaminants of emerging concern called endocrine disruptors. In the environment they are capable of interfering with reproductive processes and behaviors in fish and other aquatic life.

TBA is implanted in the ears of beef cattle. The cattle metabolize the compound to produce 17-alpha-trenbolone, an endocrine disruptor that is chemically close to TBA. The metabolite makes its way to streams and rivers via manure that washes from feedlots or is applied to land as fertilizer. The compound breaks down rapidly when exposed to sunlight, and regulators once thought this attribute greatly reduced its environmental risk. But a 2013 study by Cwiertny, Kolodziej and others found that the breakdown products reverted back to 17-alpha-trenbolone in the dark. This means that, instead of permanent removal in sunlight, the compound would be expected to persist in stream environments, returning to its earlier form overnight in the dark, shallow streambed where stream water mixes with groundwater, known as the hyporheic zone.

Ward and his collaborators set out to learn how much longer trenbolone may persist in the environment because of its unique reactivity, and whether this added persistence matters for aquatic ecosystems. Using mathematical modeling techniques, they show that concentrations of TBA metabolites may be about 35 percent higher in streams than previously thought. And the compounds persist longer, resulting in 50 percent more biological exposure than anticipated. That’s a problem, Ward said, because even very low concentrations of these powerful endocrine disruptors have been shown to have significant effects on stream life.

“These compounds have the potential to disrupt entire ecosystems by altering reproductive cycles in many species, including fish,” Ward said. “We expect impacts that extend through the aquatic food web.” Studies by the U.S. Geological Survey and other agencies have found endocrine disruptors to be present in many streams, rivers and lakes, and several similar compounds have even been found in drinking water. While TBA and its metabolites are the focus of the study, Ward said those compounds are representative of many others — suggesting it may be time to update regulatory approaches to better include a wide range of findings from modern research.

“Our focus on individual compounds has been highly successful in getting us where we are today, which is some of the cleanest water in the world,” Ward said. “The next step is thinking about unexpected reactions that occur in the environment and how we can manage the diverse group of potential products and their joint effect on the environment and human health.”  Science Daily  Original web page at Science Daily


* Humans, livestock in Kenya linked in sickness and in health

If a farmer’s goats, cattle or sheep are sick in Kenya, how’s the health of the farmer? Though researchers have long suspected a link between the health of farmers and their families in sub-Saharan Africa and the health of their livestock, a team of veterinary and economic scientists has quantified the relationship for the first time in a study. Writing in the journal Plos One, authors say the study offers a unique view of human health through the lens of animal health.

After tracking 1,500 households and their livestock in 10 western Kenyan villages for one year, researchers found a strong relationship between the number of illnesses among family members and the number of livestock sicknesses and deaths in the same household. Using hut-to-hut visits and free hotline numbers for farmers to call on mobile phones, researchers obtained data on 6,400 adults and children, along with more than 8,000 cattle, 2,400 goats, 1,300 sheep and 18,000 chickens. Analysis of that data revealed this: For every 10 cases of animal illness or death that occurred, the probability of human sickness in the same household shot up by 31 percent.

“Our findings help to understand, in quantitative terms, the complex pathways that link livestock health to the health and welfare of the humans who own them,” said Kenya-based lead author Thumbi Mwangi, an infectious disease epidemiologist at Washington State University’s Paul G. Allen School for Global Animal Health. “It’s important because an estimated 300 million people living in sub-Saharan Africa depend on their livestock as a main source of livelihood and nutrition,” he said. Human health and animal health are connected by three pathways, Mwangi and his co-authors state: socio-economic, where healthy and productive livestock result in higher household incomes and increased access to education and health care; nutritional, where healthy livestock increase access to animal source foods, which, in turn, lowers malnutrition and disease; zoonotic, where healthy livestock are less likely to transmit zoonotic diseases–those that spill over from animals to humans, including food-borne infections.

Livestock benefit families in multiple ways but the negative side of disease must also be considered, the authors argue. They studied 1,500 households spanning a rural region stricken by poverty and infectious diseases. Using bi-weekly home survey visits by veterinary teams and toll-free calls from farmers, the researchers found that households with livestock experiencing high numbers gastrointestinal and respiratory syndromes “have high numbers of the similar syndromes in humans.”

What’s not known is whether animals suffering from those ailments are passing the pathogens directly to the people who own them. It’s also possible that the environment where they live fosters propagation of those pathogens, the scientists write. In their next phase of study, they will try to pinpoint the underlying causes.  Science Daily  Original web page at Science Daily


Stomach ulcers in cattle: Bacteria play only a minor role

Scientists at the University of Veterinary Medicine Vienna investigated whether stomach ulcers in cattle are related to the presence of certain bacteria. For their study, they analysed bacteria present in healthy and ulcerated cattle stomachs and found very few differences in microbial diversity. Bacteria therefore appear to play a minor role in the development of ulcers. The microbial diversity present in the stomachs of cattle has now for the first time been published in the journal Veterinary Microbiology.

Gastritis and stomach ulcers in humans are often caused by the bacterium Helicobacter pylori. But other factors, such as stress and nutrition, also play a role in stomach health. In cattle the weather and husbandry in general play an additional role. The etiological role of bacteria in abomasal ulcers was investigated by veterinarian Alexandra Hund of the Clinical Unit of Ruminant Medicine together with microbiologist Stephan Schmitz-Esser of the Institute for Milk Hygiene. “The abomasum is the last of the four stomach compartments in cattle. The three other compartments, the rumen, the reticulum and the omasum, serve to predigest the food. The abomasum is the actual stomach and is similar in anatomy and function to the human stomach. Painful gastritis and ulcers can occur in the abomasa of cattle, potentially weakening the animals, leading to perforations of the stomach and possibly even to cases of death,” first author Alexandra Hund explains.

Microbiologist Schmitz-Esser analysed stomach samples from slaughter cattle. Around half of the samples were taken from healthy cattle, the other half from cattle with low-grade abomasal ulcers. “Very sick animals are barred from slaughter,” says Alexandra Hund. The researchers isolated and sequenced the bacterial DNA from the stomach samples. The DNA sequences were then used to determine the type of bacteria present. “The most common were species of Helicobacter, Acetobacter, Lactobacillus and new strains of Mycoplasma. The bacterium Helicobacter pylori, commonly found in humans, was not present at all. We nearly saw the same bacterial composition in healthy and ulcerated animals, which suggests that bacteria only play a minor role in the etiology of abomasal ulcers,” says Schmitz-Esser. “However, this is something we would like to underpin in future studies.”

Calf stomachs contain a relatively immature microbial biomass. This means that bacterial diversity must still develop. The primary bacteria found in calf stomachs were beneficial lactic acid bacteria. These bacteria enter the stomachs of calves through the milk that forms their main source of nutrition. “Due to the very subtle symptoms of abomasal ulcers, they are very difficult to diagnose for non-experts. The abomasum is the last of the four stomach compartments and therefore not accessible to gastroscopy. We are currently working on a method for the early and rapid diagnosis of those ulcers. In any case, keeping cattle stress-free is one way of preventing stomach ulcers,” Alexandra Hund recommends.  Science Daily  Original web page at Science Daily


* Gene in high-altitude cattle disease sheds light on human lung disease

Vanderbilt University researchers have found a genetic mutation that causes pulmonary hypertension in cattle grazed at high altitude, and which leads to a life-threatening condition called brisket disease. Their findings, reported in Nature Communications, may shed light on human lung disease, in particular, the mechanism behind non-familial pulmonary hypertension in patients with conditions such as emphysema and pulmonary fibrosis. “A genetic variant in cattle might tell us why some humans get into trouble at sea level and at altitude,” said first author John H. Newman, M.D., the Elsa S. Hanigan Professor of Pulmonary Medicine at Vanderbilt University Medical Center. When the lung experiences low oxygen, or hypoxia, the blood vessels of the lung constrict. Over time in continued hypoxic conditions, these vessels become muscularized, resulting in pulmonary hypertension, high blood pressure in the blood vessels of the lung.

Lowland cattle can develop pulmonary hypertension after being at high altitude over a period of six months to a year. Brisket disease, or right heart failure, develops when the heart fails to pump against the high pulmonary blood pressure. If these animals are not brought to lower altitudes, they will die. Brisket disease costs millions of dollars of loss each year in the Rocky Mountains, where the herds graze. Fifteen years ago, Newman, James Loyd, M.D., Rudy W. Jacobson Professor of Pulmonary Medicine, and colleagues identified the genetic basis for familial pulmonary hypertension in humans, mutations in a gene called BMPR2. “I was sitting in our conference room after we had found the BMPR2 gene in humans and I thought, well, we should be able to find the brisket gene in cattle using the same strategy,” Newman said.

In collaboration with Timothy Holt, D.V.M., an internationally known expert on brisket disease at Colorado State University, the Vanderbilt group set out to identify a genetic component for this condition. Holt evaluated cattle herds for pulmonary hypertension and sent blood samples to the lab of John A. Phillips III, M.D., where DNA was extracted and analyzed. Phillips is David T. Karzon Professor of Pediatrics and director of the Vanderbilt Division of Medical Genetics and Genomic Medicine. Newman, Phillips and their colleagues, including Rizwan Hamid, M.D., Ph.D., Joy Cogan, Ph.D., and James West, Ph.D., discovered that most of the cattle with high-altitude pulmonary hypertension had a double mutation in a single gene that expresses hypoxia inducible factor, HIF2alpha. At low altitude, the HIF2alpha protein is continually degraded and has no effect. However, in a hypoxic environment, it is activated and initiates a series of events to combat physiological effects of low oxygen.

The mutation found in the cattle renders the protein resistant to degradation, resulting in excessive pulmonary hypertension. The Vanderbilt group is currently working on a test to help ranchers determine which cows carry the genetic susceptibility and should remain at low altitude. This test might reduce the prevalence of brisket disease and save ranchers costly losses of stock.  Science Daily  Original web page at Science Daily


* Minimizing ‘false positives’ key to vaccinating against bovine TB

Using mathematical modelling, researchers at the University of Cambridge and Animal & Plant Health Agency, Surrey, show that it is the specificity of the test — the proportion of uninfected animals that test negative — rather than the efficacy of a vaccine, that is the dominant factor in determining whether vaccination can provide a protective economic benefit when used to supplement existing controls.

Bovine TB is a major economic disease of livestock worldwide. Despite an intensive, and costly, control programme in the United Kingdom, the disease continues to persist. Vaccination using the human vaccine Mycobacterium bovis bacillus Calmette-Guérin (BCG) offers some protection in cattle, but is currently illegal within the European Union (EU) due to its interference with the tuberculin skin test. This test is the cornerstone of surveillance and eradication strategies and is used to demonstrate progress towards national eradication and as the basis of international trade in cattle. The current tuberculin skin test has a very high estimated specificity of over 99.97%, which means that less than three animals in 10,000 will test falsely positive. The test as carried out in Great Britain is thought to have at best an 80% sensitivity — a measure of how many infected animals will correctly test positive — missing around 1 in 5 bovine TB-infected cattle. It is used to determine if animals, herds and countries are officially free of bovine TB. Vaccinated animals that test positive have to be treated as infected animals. Under European law, if an animal tests positive, it must be slaughtered. The remaining herd is put under movement restrictions and tested repeatedly using both the skin test and post-mortem examinations until it can be shown to be officially clear of infection. The duration of movement restrictions is important due to the considerable economic burden they place on farms. The cost to the UK government alone, which depends on the number of visits to farms by veterinarians, tests carried out and compensation for the slaughter of infected animals, is estimated to be up to £0.5 billion pounds over the last ten years.

For vaccination to be feasible economically and useful within the context of European legislation, the benefits of vaccination must be great enough to outweigh any increase in testing. A new generation of diagnostic tests, known as ‘Differentiate Vaccinated from Infected Animals’ (DIVA) tests, opens up the opportunity for the use of BCG within current control programmes. The EU has recently outlined the requirements for changes in legislation to allow cattle vaccination and a recent report from its European Food Safety Authority emphasized the importance of demonstrating that BCG is efficacious and that DIVA tests can be shown to have a comparable sensitivity to tuberculin testing in large-scale field trials.

However, a key factor overlooked in this report was that the currently viable DIVA tests have a lower specificity than tuberculin testing; this could lead to vaccinated herds being unable to escape restrictions once a single test-positive animal has been detected, as the more times the herd is tested, the more likely the test is to record a false positive. In the study published recently, the researchers from Cambridge and the Animal & Plant Health Agency used herd level mathematical models to show that the burden of infection can be reduced in vaccinated herds even when DIVA sensitivity is lower than tuberculin skin testing — provided that the individual level protection is great enough. However, in order to see this benefit of vaccination the DIVA test will need to achieve a specificity of greater than 99.85% to avoid increasing the duration and number of animals condemned during breakdowns. A data set of BCG vaccinated and BCG vaccinated/experimentally M. bovis infected cattle suggests that this specificity could be achievable with a relative sensitivity of the DIVA test of 73.3%. However, validating a test to such a high specificity will likely prove a challenge. Currently, there is no gold standard test to diagnose TB in cattle. Cattle that test positive are slaughtered immediately and therefore have rarely developed any physical signs — in fact, only around a half of animals examined post-mortem show physical signs of infection even if they are, indeed, infected. Dr Andrew Conlan from the Department of Veterinary Medicine at the University of Cambridge says: “In order for vaccination to be viable, we will need a DIVA test that has extremely high specificity. If the specificity is not good enough, the test will find false positives, leading to restrictions being put in place and a significant financial burden for the farmer. But validating a test that has a very high specificity will in itself be an enormous challenge. We would potentially need to vaccinate, test and kill a large number of animals in order to be confident the test is accurate. This would be very expensive.”

The need for a better DIVA test was acknowledged by the Government at the end of last year. In a written statement to the House of Commons noting data from the University of Cambridge and Animal Health and Veterinary Laboratories Agency, the Rt Hon Elizabeth Truss, Secretary of State for Environment, Food and Rural Affairs, said: “An independent report on the design of field trials of cattle vaccine and a test to detect infected cattle among vaccinated cattle (DIVA) shows that before cattle vaccination field trials can be contemplated, we need to develop a better DIVA test.” Science Daily Original web page at Science Daily


New salmonella serotype discovered

The latest honor to come Lubbock’s way may not sound good at first, but when realizing it’s a breakthrough in biological sciences, it will become something to brag about. Marie Bugarel, a research assistant professor at Texas Tech University’s Department of Animal and Food Sciences in the College of Agricultural Sciences and Natural Resources, has discovered a new serotype of the salmonella bacteria. The new serotype was confirmed by the Pasteur Institute in Paris, the international reference center for salmonella. Because convention calls for a new serotype to be named after the city in which it is discovered, this one will be called Salmonella Lubbock (officially Salmonella enterica subsp. enterica Lubbock). “More important than the name, however, is that this discovery illustrates there is more that needs to be discovered about salmonella and how it interacts with cattle populations,” said Guy Loneragan, a professor of food safety and public health who, along with Kendra Nightingale, are Bugarel’s mentors at Texas Tech. “With this understanding will come awareness of how to intervene to break the ecological cycle and reduce salmonella in animals and in beef, pork and chicken products.” Bugarel, who came to Texas Tech with an extensive background in salmonella research, has worked on developing new tools to detect salmonella, new approaches to distinguish serotypes and ways to understand salmonella’s biology. Her work has led to a patent application that has been licensed to a high-tech biosciences research company. Her invention means it is now possible to simultaneously detect and distinguish specific strains of salmonella by targeting a specific combination of DNA. That will allow for early detection in food while also identifying whether or belongs to a highly pathogenic strain.

In her research for Salmonella Lubbock, the impetus was to reduce salmonella in food and improve public health. She focused on providing solutions to control salmonella in cattle population, which led to a better understanding of the biological makeup of salmonella itself, including its genetic makeup. Through this approach, Bugarel discovered the new strain never before described. The long-held standard way of distinguishing one strain of salmonella from another is called serotyping and is based on the molecules on the surface of the bacterium. Each serotype has its own pattern of molecules, called antigens, and the collection of molecules provides a unique molecular appearance. These antigens interact with certain antibodies found in specifically prepared serum, thus providing the serotype. It is similar to how blood typing is performed. “This discovery reinforces my feeling that the microbiological flora present in cattle in the United States harbors a singularity, which is an additional justification of the research we are doing in the International Center for Food Industry Excellence (ICFIE) laboratories at Texas Tech,” Bugarel said. “Additional research will be performed to better describe the characteristics of this atypical bacterial flora and, more specifically, of the Lubbock serotype.”

With this discovery, Loneragan believes between 20 and 30 percent of two current strains, Salmonella Montevideo and Salmonella Mbandaka, will be reclassified as Salmonella Lubbock. The algorithm used in serotyping has some stopping points, but Bugarel discovered a need to go a step further to get the correct strain name. Therefore some of those strains called Montevideo and Mbandaka are now Salmonella Lubbock. Some of the strains of Salmonella Lubbock fall into the category of serotype patterns that are more broadly resistant to many families of antibiotics, furthering the need for more research on the subject. Human susceptibility to the Lubbock strains remains unknown. “We will continue to develop methods to detect, identify and control the presence of pathogenic microorganisms in food products in order to improve food safety and public health,” Bugarel said. “Kendra and I have been honored to serve as Marie’s mentors,” Loneragan said. “But now, the growth in Marie’s expertise means that she is becoming the mentor to us. Many students, and the citizens of the United States in general and Texas in particular, are benefitting from her commitment to research excellence at Texas Tech. We are very lucky to have her.” Science Daily Original web page at Science Daily


* Testing for Bovine Tuberculosis is more effective than badger culls at controlling the disease

Modelling produced by researchers at Queen Mary University of London (QMUL) has found that the only effective potential Bovine Tuberculosis (TB) control strategies are badger culling, cattle testing, controlling cattle movement, and ceasing the practice of housing farm cattle together during winter. The modelling found that in a region containing about 1.5m cows of which 3000 to 15,000 might have TB, badger culling could account for a reduction of 12 in the number of infected cattle. While reducing the testing interval by one month could reduce the number of those infected by 193. The model showed that regular and frequent testing of cattle could eventually lead to the eradication of the disease, whether or not badgers were culled and despite the current test being at most 80% accurate. Badger culling alone, however did not lead to TB eradication in the study and is therefore unlikely to be a successful control strategy. The model also suggested that housing cattle in large sheds over winter could potentially double the number of infected animals in a herd, as under such conditions there is a much greater chance of TB being passed between cows. This is the first large-scale model of TB in cattle and badgers that included the possibility of the infection being passed in both directions between the two species. The model successfully mimicked the changing patterns of TB in the UK, including the changes seen after TB controls were reduced during the foot-and-mouth epidemic of 2002. Researchers Dr Aristides Moustakas and Professor Matthew Evans, of QMUL’s School of Biological and Chemical Sciences, used state-of-the-art computer modelling to understand how the interaction of different factors impacted on infection rates. Such factors included the movement and life-cycles of badgers and cattle; how cattle are moved and housed; how frequently cattle are tested, different types of badger culling; and the infection rates between animals. The research is published online in Stochastic Environmental Research and Risk Assessment. Professor Matthew Evans, Professor of Ecology at QMUL, said: “Of the available Bovine Tuberculosis control strategies we believe that how frequently cattle are tested and whether or not farms utilise winter housing have the most significant effect on the number of infected cattle.” “TB is a complex disease and modelling it is difficult but we’ve successfully used our model to replicate real world situations and are confident that it can be used to predict the effects of various changes in the way we tackle the disease.” “Our modelling provides compelling evidence, for those charged with controlling Bovine TB, that investment in increasing the frequency of cattle testing is a far more effective strategy than badger culling.”  Science Daily Original web page at Science Daily


* Manure fertilizer increases antibiotic resistance

Pseudomonas bacteria in soil benefit from manure fertilizer treatments. Treating dairy cows and other farm animals with antibiotics and then laying their manure in soil can cause the bacteria in the dirt to grow resistant to the drugs. But a study now suggests that the manure itself could be contributing to resistance, even when it comes from cows that are free of antibiotics. The mechanism at work is not yet clear, but the finding — published on 6 October in Proceedings of the National Academy of Sciences — suggests a complex link between antibiotic use in agriculture and resistance in human pathogens. Many bacteria in the environment naturally carry antibiotic-resistance genes, probably as defence against the antibiotics produced by some soil fungi and bacteria. Laboratory-made versions of these antibiotics are used to treat infection in humans and animals, and to promote growth in livestock. Because manure itself is known to change the composition of bacterial communities in soil, a team led by microbiologist Jo Handelsman, then at Yale University in New Haven, Connecticut, decided to examine whether it also affects drug resistance. The team treated soil samples with either a nitrogen-based fertilizer or with manure from cows that had never been fed antibiotics. The researchers examined soil bacteria sampled before and after the treatment, searching for genes that encode enzymes called β-lactamases, which break down a class of antibiotic that includes penicillin. Two weeks after treatment, the soil spread with manure contained significantly higher numbers of bacteria producing β-lactamases than did soil treated with only the nitrogen-based fertilizer. By tracing genetic markers in the resistant bacteria, the researchers found that these bacteria came from the soil rather than from the manure, suggesting that the manure treatment had helped these natural bacteria to grow by feeding them or eliminating their competitors. The manure was particularly beneficial for Pseudomonas species, which are common in human infections. But it is unclear how manure creates a better environment for antibiotic-resistant bacteria. Handelsman — now associate director for science at the White House Office of Science and Technology Policy — and her colleagues suggest that certain nutrients or heavy metals in the manure could be responsible, because bacteria with β-lactamases are also more likely to be resistant to metals. The authors say that they plan to test this in the future.  Nature  Original web page at Nature


Natural intrauterine infection with Schmallenberg virus in malformed newborn calves

We surveyed morphologic alterations in calves in Belgium that were naturally infected in utero by Schmallenberg virus (SBV) and born with deformities during January–March 2012. SBV-specific RNA was distributed unevenly in different tissues. Natural intrauterine SBV infection of calves might cause serious damage to the central nervous system and muscles. During summer and fall 2011, a nonspecific febrile syndrome characterized by hyperthermia and decreased milk production was reported in adult dairy cows from farms in the Netherlands and Germany. In November 2011, an enzootic outbreak of abortions, stillbirths, and term births of lambs, kids, and calves that exhibited neurologic signs and/or musculoskeletal malformations emerged throughout northwestern Europe. Both syndromes were associated with the presence in the blood (adults) or in the central nervous system (CNS) (newborns) of the genome of a new orthobunyavirus, which was named Schmallenberg virus (SBV) after the place where the first positive samples were collected. SBV belongs to the Simbu serogroup and, like its phylogenetic relatives Akabane and Aino viruses, can cross the placenta. Because this new viral disease of ruminants emerged 3 years ago, information is limited. We comprehensively surveyed morphologic alterations in calves naturally infected in utero. In addition, we report the distribution of SBV-specific RNA in the different tissues of these calves, which has implications for diagnosis. In Belgium each year during January–June, field veterinarians refer ≈30 newborn calves per month for necropsy to the University of Liège Faculty of Veterinary Medicine (Liège, Belgium). During January–March 2012, the consequences of SBV infection on bovine fetuses were not yet known, which prompted the staff to look systematically for the new virus in all deformed calves and in calves that died spontaneously without obvious cause. Among the 67 animals in these categories, SBV genetic material was detected in 15 calves by reverse transcription quantitative PCR, and IgG specific for SBV nucleoprotein was systematically highlighted in their serum by ELISA. In addition, all attempts to retrieve the genetic material of bluetongue virus 8 and bovine viral diarrhea virus from the tissues of these 15 seropositive calves failed. None of these calves carried the mutation responsible for noninfectious arthrogryposis in local livestock. These 15 calves, in which both SBV RNA and antibodies against SBV were detected, are the subject of this study. We observed overall permanent deviations of the axial skeleton in all 3 the most common being a lateral deviation of the cervical spine (torticollis). In the most distorted animals, the torticollis was accompanied by a dorso-ventral deviation of the thoracolumbar spine. Most SBV-infected calves displayed joint fixation of 1 or all joints of >1 limbs (arthrogryposis). Tendons spanning fixed joints were shorter than expected, and corresponding muscles displayed decreased mass and altered color. Often the animal’s head was distorted, having a horse-like or pig-like shape, brachygnathism, prognathism, and/or diverging sagittal axes. Read more: Emerging Infectious Diseases  Emerging Infectious Diseases


Evolutionary biology: Why cattle, pigs only have two toes

The fossil record shows that the first primitive even-toed ungulates had legs with five toes (=digits), just like modern mice and humans. During their evolution, the basic limb skeletal structure was significantly modified such that today’s hippopotami have four toes, while the second and fifth toe face backwards in pigs. During evolutionary diversification of vertebrate limbs, the number of toes in even-toed ungulates such as cattle and pigs was reduced and transformed into paired hooves. Scientists at the University of Basel have identified a gene regulatory switch that was key to evolutionary adaptation of limbs in ungulates. The study provides fascinating insights into the molecular history of evolution and is published by Nature today. The fossil record shows that the first primitive even-toed ungulates had legs with five toes (=digits), just like modern mice and humans. During their evolution, the basic limb skeletal structure was significantly modified such that today’s hippopotami have four toes, while the second and fifth toe face backwards in pigs. In cattle, the distal skeleton consists of two rudimentary dew claws and two symmetrical and elongated middle digits that form the cloven hoof, which provides good traction for walking and running on different terrains. A team led by Prof. Rolf Zeller from the Department of Biomedicine at the University of Basel has now investigated the molecular changes which could be responsible for the evolutionary adaptation of ungulate limbs. To this aim, they compared the activity of genes in mouse and cattle embryos which control the development of fingers and toes during embryonic development. The development of limbs in both species is initially strikingly similar and molecular differences only become apparent during hand and foot plate development: in mouse embryos the so-called Hox gene transcription factors are distributed asymmetrically in the limb buds which is crucial to the correct patterning of the distal skeleton. In contrast, their distribution becomes symmetrical from early stages onward in limb buds of cattle embryos: “We think this early loss of molecular asymmetry triggered the evolutionary changes that ultimately resulted in development of cloven-hoofed distal limb skeleton in cattle and other even-toed ungulates,” says Developmental Geneticist Prof. Rolf Zeller.

The scientists in the Department of Biomedicine then focused their attention on the Sonic Hedgehog (SHH) signaling pathway, as it controls Hox gene expression and the development of five fingers and toes in mice and humans. They discovered that the gene expression in limb buds of cattle embryos is altered, such that the cells giving rise to the distal skeleton fail to express the Hedgehog receptor, called Patched1. Normally, this receptor serves as an antenna for SHH, but without Patched1 the SHH signal cannot be received and the development of five distinct digits is disrupted. The researchers could establish that the altered genomic region — a so-called cis-regulatory module — is linked to the observed loss of Patched1 receptors and digit asymmetry in cattle embryos. “The identified genetic alterations affecting this regulatory switch offer unprecedented molecular insights into how the limbs of even-toed ungulates diverged from those of other mammals roughly 55 million years ago,” explains Rolf Zeller. At this stage, it is unclear what triggered inactivation of the Patched1 gene regulatory switch. “We assume that it is the result of progressive evolution, as this switch degenerated in cattle and other even-toed ungulates, while it remained fully functional in some vertebrates such as mice and humans.”  Science Daily

July 22, 2014  Original web page at Science Daily




* Livestock gut microbes contributing to greenhouse gas emission

“Increased to levels unprecedented” is how the Intergovernmental Panel on Climate Change (IPCC) described the rise of carbon dioxide, methane and nitrous oxide emissions in their report on the physical science basis of climate change in 2013. According to the US Environmental Protection Agency (EPA), the atmospheric concentration of methane, a greenhouse gas some 28 times more potent than carbon dioxide has been steadily growing since the 18th century and has now increased by 50 percent compared to pre-industrial levels, exceeding 1,800 parts per billion. The EPA attributes one-fifth of methane emissions to livestock such as cattle, sheep and other ruminants. In fact, ruminant livestock are the single largest source of methane emissions, and in a country like New Zealand (NZ), where the sheep outnumber people 7 to 1, that’s a big deal. However, not all ruminants are equal when it comes to greenhouse gas emissions. It turns out that the amount of methane produced varies substantially across individual animals of the same ruminant species. To find out why this is so, a team of researchers led by the US Department of Energy Joint Genome Institute (DOE JGI) deployed high throughput DNA sequencing and specialized analysis techniques to explore the contents of the rumens of sheep in collaboration with NZ’s AgResearch Limited to see what role ruminant “microbiomes” (the microbes living in the rumen) play in this process. The study was published online June 6, 2014 in Genome Research. “We wanted to understand why some sheep produce a lot and some produce little methane,” said DOE JGI Director Eddy Rubin. “The study shows that it is purely the microbiota responsible for the difference.”

To learn why the amount of methane that ruminants produce varies, the researchers took advantage of a large sheep screening and breeding program in NZ that aims to breed low methane-emitting ruminants without impacting other traits such as reproduction and wool and meat quality. The team measured the methane yields from a cohort of 22 sheep, and from this group, they selected four sheep with the lowest methane emissions, four sheep with the highest emissions and two sheep with intermediate emission levels. Rumen metagenome DNA samples collected on two occasions from the 10 sheep were sequenced at the DOE JGI, generating 50 billion bases of data each. “The deep sequencing study contributes to this breeding program by defining the microbial contribution to the methane trait, which can be used in addition to methane measurements to assist in animal selection,” said senior scientist Graeme Attwood of AgResearch Limited, a senior author on the paper. The team then checked to see if there was a correlation between the proportions of methanogens in the eight sheep with the highest and lowest recorded methane emissions. In sheep with low methane emissions, they found elevated levels of one particular species of methanogen (Methanosphaera) while sheep with high methane emissions had elevated levels of another group of methanogens (Methanobrevibacter gottschalkii). Exploring further, the team then identified a methane-producing pathway and three variants of a gene encoding an important methane-forming reaction that were involved in elevated methane yields. While the overall changes to the methane-producing microbial community structure and methanogen abundance across sheep were rather subtle, the team reported that the expression levels of genes involved in methane production varied more substantially across sheep, suggesting differential gene regulation, perhaps controlled by hydrogen concentration in the rumen or by variations in the dwell time of their feed.

“It’s not so much the actual composition of the microbiome that determines emission — which conventional wisdom would suggest — but mostly transcriptional regulation within the existing microbes that makes the difference, which is a concept that is relatively new in metagenomic studies,” Rubin said. The team’s findings suggest new possible targets for mitigating methane emissions at the microbiome level. Screening and breeding for low-methane producing sheep is still underway, and importantly, low-methane lines then need to be tested for stability of the trait, as well as the absence of any impacts on fertility or meat or wool production. Moreover, as Attwood notes, “there needs to be an incentive for farmers to incorporate low methane animals into their flocks, that is, achieving better performance with the low methane animals or being able to claim carbon credits. If everything went well you could expect introduction of the low methane trait to begin in three years, and for there to be slow but incremental changes to the sheep industry in subsequent years.”  Science daily

July 22, 2014  Original web page at Science Daily


* Schmallenberg virus circulation in high mountain ecosystem, Spain

During December 29, 2012–February 21, 2013, morphologic anomalies were identified in 4 stillborn calves from different farms in northeastern Spain, and infection with SBV was suspected. The cases were clustered in the Ripollès and Garrotxa regions of Catalonia and appeared in beef cattle herds that spent the grazing season (May–November) in the alpine meadows (>2,000 m altitude) of the National Game Reserve of Freser-Setcases in the Eastern Pyrenees Mountains. The calves had severe arthrogryposis, ankylosis of several joints, abnormal curvature of the vertebral column, and severe muscle atrophy. Malformations of the central nervous system included bilateral hydrocephalus, cerebellar hypoplasia, and micromyelia, characterized by the presence of few neurons in the ventral horns and moderate to severe bilateral reduction of white matter in the ventral and lateral funiculi. SBV infection was confirmed by real-time reverse transcription qualitative PCR (RT-qPCR) or serologic testing in 3 of the 4 calves and all 4 of the mothers. Serum samples were tested by using a commercial indirect ELISA (; Innovative Diagnostics, Montpellier, France) and a virus neutralization test using the BH80/11–4 isolate (provided by the Friedrich-Loeffler-Institut, Isle of Riems, Germany). Consistent results were obtained from both of these techniques, and the proportions of calves positive by ELISA and RT-qPCR were similar to those found in previous studies. The neurologic and musculoskeletal lesions found in the calves indicated that fetal infection probably occurred at 5–6 months’ gestation. Gestation started in mid-April to mid-May; therefore, maternal infection most probably occurred in late summer 2012 (September–October), when cows were grazing in the alpine meadows.

We then performed a serologic study in domestic and sympatric wild ruminants from the National Game Reserve of Freser-Setcases, which comprises 20,200 ha of alpine and subalpine ecosystems. We analyzed serum samples from 355 wild ruminants hunted during August 2010–May 2013; species sampled included Pyrenean chamois (Rupicapra pyrenaica), European mouflon (Ovis aries musimon), and roe deer (Capreolus capreolus). We also analyzed samples from fetuses of these species obtained in April 2013, as well as animals from 8 cow herds and 4 sheep–goat mixed herds; a mean of 14 samples were collected per herd during 2 sampling periods. Two of the mixed sheep–goat herds were sampled during both sampling periods. All serum samples underwent ELISA testing; positive results were confirmed by virus neutralization. Domestic ruminants sampled during October–November 2011 were seronegative, whereas all farms sampled during November 2012–April 2013 had infected animals. High mean seroprevalence was found in cow herds; 105 (86.8% [95% CI 80.7%–92.8%]) of 121 herds tested were infected. Seroprevalance was lower but still high for mixed sheep–goat herds; 16 (41% [95% CI 25.6%–56.5%]) of 39 herds were infected. The earliest evidence of SBV in the study area came from a seropositive Pyrenean chamois hunted on September 3, 2012; this date coincides with the estimated months when cows that delivered stillborn calves were infected. For wild ungulates tested from September 2012 onwards, overall SBV seroprevalence was statistically higher (χ2 33.47, 2 d.f., p<0.0001) in roe deer (4/5, 80% [95% CI 44.9%–100%]) than in Pyrenean chamois (8/105, 7.6% [95% CI 2.5%–12.7%]) and mouflon (0/23). Differences in seroprevalence for summer through autumn 2012 compared with spring 2013 in Pyrenean chamois were not significant.  Emerging Infectious Diseases

June 24, 2014  Original web page at Emerging Infectious Diseases


Cougars’ diverse diet helped them survive the mass extinction that wiped out the saber-tooth cat, American lion

Cougars may have survived the mass extinction that took place about 12,000 years ago because they were not particular about what they ate, unlike their more finicky cousins — the saber-tooth cat and American lion. Both perished along with the woolly mammoth and many of the other supersized mammals that walked Earth during the late Pleistocene. That is the conclusion of a new analysis of the microscopic wear marks on the teeth of cougars, saber-tooth cats and American lions described in the April 23 issue of the journal Biology Letters. “Before the Late Pleistocene extinction six species of large cats roamed the plains and forests of North America. Only two — the cougar and jaguar — survived. The goal of our study was to examine the possibility that dietary factors can explain the cougar’s survival,” said Larisa R.G. DeSantis, assistant professor of earth and environmental sciences at VanderbiltUniversity, who co-authored the study with Ryan Haupt at the University of Wyoming. For their investigation, DeSantis and Haupt employed a new technique called dental microwear texture analysis. DMTA uses a confocal microscope to produce a three-dimensional image of the surface of a tooth. The image is then analyzed for microscopic wear patterns. The analysis of the teeth of modern carnivores, including hyenas, cheetahs and lions has established that the meals an animal consumes during the last few weeks of its life leave telltale marks. Chowing down on red meat, for example, produces small parallel scratches while chomping on bones adds larger, deeper pits. The researchers analyzed the teeth of 50 fossil and modern cougars, and compared them with the teeth of saber-tooth cats and American lions excavated from the La Brea Tar Pits in Los Angeles and the teeth of modern African carnivores including cheetahs, lions and hyenas.

Previously, DeSantis and others found that the dental wear patterns of the extinct American lions closely resembled those of modern cheetahs, which are extremely finicky eaters that mostly consume tender meat and rarely gnaw on bones. Saber-tooth cats were instead similar to African lions and chewed on both flesh and bone. Among the La Brea cougars the researchers found significantly greater variation between individuals than they did in the other large cats, including saber-toothed cats. Some of the cougars show wear patterns similar to those of the finicky eaters but on others they found wear patterns closer to those of modern hyenas, which consume almost the entire body of their prey, bones included. “This suggests that the Pleistocene cougars had a ‘more generalized’ dietary behavior,” DeSantis said. “Specifically, they likely killed and often fully consumed their prey, more so than the large cats that went extinct.” This is consistent with the dietary behavior and dental wear patterns of modern cougars, which are opportunistic predators and scavengers of abandoned carrion and fully consume the carcasses of small and medium-sized prey, a “variable dietary behavior that may have actually been a key to their survival.”  Science Daily

May 13, 2014  Original web page at Science Daily


* Cow manure harbors diverse new antibiotic resistance genes

Manure from dairy cows, which is commonly used as a farm soil fertilizer, contains a surprising number of newly identified antibiotic resistance genes from the cows’ gut bacteria. The findings, reported in mBio® the online open-access journal of the American Society for Microbiology, hints that cow manure is a potential source of new types of antibiotic resistance genes that transfer to bacteria in the soils where food is grown. Thousands of antibiotic resistance (AR) genes have already been identified, but the vast majority of them don’t pose a problem when found in harmless bacteria. The real worry is when these genes appear in the types of pathogenic bacteria that cause food-borne illnesses or hospital infections. “Since there is a connection between AR genes found in environmental bacteria and bacteria in hospitals, we wanted to know what kind of bacteria are released into the environment via this route,” of manure fertilization, says Fabienne Wichmann, lead study author and former postdoctoral researcher at Yale University in New Haven, Connecticut. Farmers use raw or composted cow manure on some vegetable crops, which could lead to a scenario where residual manure bacteria might cling to produce and they or their genes might move to the human ecosystem. “Is this a route for movement of these genes from the barn to the table?” asks Jo Handelsman, senior study author and microbiologist at Yale. The first step toward an answer was surveying which AR genes are present in cow manure. Handelsman’s team used a powerful screening-plus-sequencing approach to identify 80 unique and functional AR genes. The genes made a laboratory strain of Escherichia coli bacteria resistant to one of four types of antibiotics — beta-lactams (like penicillin), aminoglycosides (like kanamycin), tetracycline, or chloramphenicol.

Roughly 75% of the 80 AR genes had sequences that were only distantly related to AR genes already discovered. The team also found an entire new family of AR genes that confer resistance to chloramphenicol antibiotics, which are commonly used to treat respiratory infections in livestock. “The diversity of genes we found is remarkable in itself considering the small set of five manure samples,” says Handelsman, who is also a Howard Hughes Medical Institute Professor. “But also, these are evolutionarily distant from the genes we already have in the genetic databases, which largely represent AR genes we see in the clinic.” That might signal good news that AR genes from cow gut bacteria are not currently causing problems for human patients. But, Wichmann points out, another possibility is that “cow manure harbors an unprecedented reservoir of AR genes” that could be next to move into humans. “This is just the first in a sequence of studies — starting in the barn, moving to the soil and food on the table and then ending up in the clinic — to find out whether these genes have the potential to move in that direction,” says Handelsman. AR genes can enter the human ecosystem by two routes — either the bacteria that contain them colonize humans, or the genes are transferred through a process called horizontal gene transfer to other bacteria that colonize humans. Research has already shown that bacteria are transferred from farm animals to their human caretakers. Gene transfer enables genes to jump between microorganisms that are not related, and it occurs in most environments that host bacteria. Some manure bacteria might be pathogenic to humans, so if they acquire antibiotic resistance, they could pose a problem. Alternatively, benign bacteria in manure might transfer resistance genes to pathogens at any point along the path — in manure, soil, food, or humans. “We’re hoping this study will open up a larger field of surveillance, to start looking at new types of resistance before they show up in the clinic,” says Handelsman. Science Daily

May 13, 2014 Original web page at Science Daily


Moms favor daughters in dairy study

A study of 2.39 million lactation records from 1.49 million dairy cows showed that cows produce significantly more milk for daughters than for sons across lactation, said Barry Bradford, associate professor in K-State’s Department of Animal Sciences and Industry. He, along with Katie Hinde in Harvard’s Department of Human Evolutionary Biology, Abigail Carpenter, K-State graduate student and John Clay, with Dairy Records Management Systems collaborated on the study. “Our results provide the first direct evidence that the sex of a gestating fetus can influence milk production,” Bradford said. “One possible explanation is that a daughter is able to let her mom know, in advance, that she expects to receive more milk than her brothers. ”In addition, the researchers found that the sex of the fetus a cow is carrying can enhance or diminish the production of milk during an established lactation and that the sex of the fetus gestated in the first pregnancy has persistent consequences for milk production on the second lactation. The study could have implications for humans, Hinde said. “Among the surprises in this study was the fact that the bias was in favor of daughters rather than sons, as some evolutionary hypotheses have predicted. Daughters seemed to have the most dramatic effect on the initial development of the mammary gland, because the bias against sons was greatest in the first lactation,” Bradford said.

The team also found that the percent fat and protein in milk did not differ between cows that gestated a son or daughter, so the quality of milk was the same. However, because the quantity was greater after gestating a daughter, the total amount of milk fat and protein after gestating a daughter were higher than after gestating a son. Standardized husbandry in the dairy industry, combined with systematic milking procedures, detailed record-keeping, and large sample sizes made the dairy cow a powerful model for the exploration of milk synthesis. The study was derived from all lactation records from 1995 to 1999 in a database managed by Dairy Records Management Systems of Raleigh, N.C. How does the fetus influence milk synthesis? It’s likely that hormones from the fetus and placenta differ between fetal sons and daughters. Those hormones may subsequently enter the maternal bloodstream and affect milk-producing cells in the mammary gland, the researchers said in a Jan. 22 statement. “After finding the programming effect of fetal sex on subsequent lactations, our team discussed the possibility that daughters were releasing hormones into the maternal circulation that could directly influence the mammary gland,” Bradford said. “It occurred to us that if this was true, becoming pregnant with a daughter might influence milk production even in an ongoing lactation. I was floored when we tested that effect and found it to be significant as well.”

Cows with two daughters back-to-back produced about 445 kilograms – or about 980 pounds – more milk across the first two lactations than did cows with back-to-back sons, he said. Artificial insemination is standard practice in the dairy industry and sex-selected semen is an option for producers to buy. “According to our rough calculations, taking into account the wholesale value of milk, the number of two-year-old heifers added to U.S. dairy herds annually, the production advantage across the first two lactations of conceiving a daughter on the first pregnancy, and the increased probability of conceiving a daughter from sex-selected semen, suggests a gross value in the neighborhood of $200 million in milk production across the first two lactations alone,” the team reported. “Well no study has yet systematically addressed differences in milk for sons and daughters in terms of both composition and yield,” said Hinde. “But in the last couple years there have been a handful of studies among humans reporting differences in milk composition between sons and daughters. Humans have a very invasive placenta that would allow fetal hormones to pass into maternal circulation and possibly influence mammary gland development. But it hasn’t yet been systematically studied.” “This research in cows demonstrates that the fetus can influence the milk the mother produces during lactation and limited evidence suggests that similar processes may be operating in humans,” she added. “Such a finding has potential implications for nutrition management of babies in neonatal intensive care units and selection of donor milks. And such research can inform infant formulas tailored more specifically to the physiological needs of sons and daughters.” Science Daily
February 18, 2014 Original web page at Science Daily


Sequence of water buffalo completed

Bangladesh with strong hybrid research program, and BGI, the world’s largest genomics organization, jointly announced today that they have completed the genome sequencing of water buffalo and the bioinformatics analysis. The outstanding work lays an important foundation for molecular breeding of water buffalo, and sheds new light on the understanding of its origin and domestication process. Buffalo is known as “Black Gold” due to its contribution to economy, which is being reared as milk, meat, hide and bone sources all over the world. In particular, it could provide more than 5% of the world’s milk supply and 20% to 30% of the farm power in Southeast Asia. Considering the importance of buffalo and realizing the need of genomic research for its improvement, Lal Teer Livestock took a great effort for “The Whole Genome Sequencing of Water Buffalo” in collaboration with BGI since March 2012. The joint efforts yielded a high-quality water buffalo genome with the size of about 2.77Gb, slightly smaller than human genome. There are 21,550 protein coding genes found in total. Researchers compared buffalo genome with other mammals’, such as cattle, horse, panda, pig, and dog for discovering more genetic characteristics of water buffalo and providing guidance for its breeding and industrial transformation.

“We are pleased to form partnership with Lal Teer Livestock to decode this important animal, ” said, Professor Jian Wang, President of BGI, “BGI is dedicated to using genomics technology to benefit human beings, and we have contributed to the sequencing of many critical crops and livestock including rice, maize, soybean, potato, pigeon pea, pig and sheep. BGI is continuing to make more progress for facing the challenges on food shortage and safety, as well contribute to the development and wellbeing of local society.” “With the joined forces with BGI, we are excited to successfully complete the task of sequencing water buffalo.” stated Mr. Tafsir Mohammed Awal, Director of Lal Teer, “This will now lay the foundation of ensuring nutrition and food security in Bangladesh and other developing countries.” Science Daily
February 18, 2014 Original web page at Science Daily


The shape of infectious prions

Prions are unique infective agents — unlike viruses, bacteria, fungi and other parasites, prions do not contain either DNA or RNA. Despite their seemingly simple structure, they can propagate their pathological effects like wildfire, by “infecting” normal proteins. PrPSc (the pathological form of the prion protein) can induce normal prion proteins (PrPC) to acquire the wrong conformation and convert into further disease-causing agents. “When they are healthy, they look like tiny spheres; when they are malignant, they appear as cubes” stated Giuseppe Legname, principal investigator of the Prion Biology Laboratory at the Scuola Internazionale Superiore di Studi Avanzati (SISSA) in Trieste, when describing prion proteins. Prions are “misfolded” proteins that cause a group of incurable neurodegenerative diseases, including spongiform encephalopathies (for example, mad cow diseases) and Creutzfeldt-Jakob disease. Legname and coworkers have recently published a detailed analysis of the early mechanisms of misfolding. Their research has just been published in the Journal of the American Chemical Society, the most authoritative scientific journal in the field.

“For the first time, our experimental study has investigated the structural elements leading to the disease-causing conversion” explains Legname. “With the help of X-rays, we observed some synthetic prion proteins engineered in our lab by applying a new approach — we used nanobodies, i.e. small proteins that act as a scaffolding and induce prions to stabilize their structure.” Legname and colleagues reported that misfolding originates in a specific part of the protein named “N-terminal.” “The prion protein consists of two subunits. The C-terminal has a clearly defined and well-known structure, whereas the unstructured N-terminal is disordered, and still largely unknown. This is the very area where the early prion pathological misfolding occurs” adds Legname. “The looser conformation of the N-terminal likely determines a dynamic structure, which can thus change the protein shape.” “Works like ours are the first, important steps to understand the mechanisms underlying the pathogenic effect of prions” concludes Legname. “Elucidating the misfolding process is essential to the future development of drugs and therapeutic strategies against incurable neurodegenerative diseases.” Science Daily
February 18, 2014 Original web page at Science Daily