Tag: Camelids

A team of scientists surveyed 335 dromedary – single humped – camels from nine herds in Laikipia County, Kenya and found that 47% tested positive for MERS antibodies, showing they had been exposed to the virus. A new study has found that nearly half of camels in parts of Kenya have been infected by the virus that causes Middle East Respiratory Syndrome (MERS) and calls for further research into the role they might play in the transmission of this emerging disease to humans.

MERS was first identified in Saudi Arabia in 2012 and there is currently no vaccine or specific treatment available. To date, it has infected 1,595 people in more than 20 countries and caused 571 deaths. Although the majority of human cases of MERS have been attributed to human-to-human infections, camels are likely to be a major reservoir host for the virus and an animal source of MERS infection in humans.

A team of scientists from the University of Liverpool and institutions in the USA, Kenya and Europe, surveyed 335 dromedary – single humped – camels from nine herds in Laikipia County, Kenya and found that 47% tested positive for MERS antibodies, showing they had been exposed to the virus.

Professor Eric Fèvre, Chair of Veterinary Infectious Diseases at the University’s Institute of Infection and Global Health said: “Although Laikipia County camel density is low relative to more northern regions of Kenya, our study suggests the population is sufficient to maintain high rates of viral transmission and that camels may be constantly re-infected and serve as long term carriers of the virus. MERS in camels, it seems, is much like being infected by the common cold.

“The significance of this is not yet clear, because we don’t know if the virus is universally zoonotic. While the risk of these camels spreading MERS to humans cannot yet be discounted, it appears to be, for now, very low as there have been no human cases diagnosed in Kenya. “It might be that the mutations required to make this virus zoonotic have only evolved recently in the Middle East, where the human outbreaks have so far been concentrated.”

Lead author Dr Sharon Deem, Director of the Saint Louis Zoo Institute for Conservation Medicine, said: “Demand for livestock products, such as meat and milk, is rising across the globe and could offer poor farmers a route out of poverty as markets expand, but zoonotic disease remains a major obstacle to this goal. “Further research to determine whether the MERS virus is dangerous to humans in Kenya and other sub-Saharan countries is critical.

The full study is published in PLOS ONE.

http://www.sciencedaily.com/  Science Dail

http://www.sciencedaily.com/releases/2015/10/151017152244.htm  Original web page at Science Daily

We found serologic evidence for the circulation of Middle East respiratory syndrome coronavirus among dromedary camels in Nigeria, Tunisia, and Ethiopia. Circulation of the virus among dromedaries across broad areas of Africa may indicate that this disease is currently underdiagnosed in humans outside the Arabian Peninsula. A novel betacoronavirus, Middle East respiratory syndrome coronavirus (MERS-CoV), was identified as the cause of severe respiratory disease in humans during 2012. In August 2013, dromedary camels (Camelus dromedarius) were implicated for the first time as a possible source for human infection on the basis of the presence of MERS-CoV neutralizing antibodies in dromedaries from Oman and the Canary Islands of Spain. Since then, the presence of MERS-CoV antibodies in dromedaries has been reported in Jordan, Egypt, the United Arab Emirates, and Saudi Arabia. In October 2013, analysis of an outbreak associated with 1 barn in Qatar found dromedaries and humans to be infected with nearly identical strains of MERS-CoV. Further proof of widespread circulation of MERS-CoV among dromedaries was provided by studies from Egypt and Saudi Arabia. These findings have raised questions about the geographic distribution of MERS-CoV among camel populations elsewhere. Here, we report our assessment of the geographic distribution of MERS-CoV circulation among dromedaries in Africa by serologic investigation of convenience samples from these animals in Nigeria, Tunisia, and Ethiopia. Read more: http://wwwnc.cdc.gov/eid/article/20/8/14-0590_article

http://wwwnc.cdc.gov/eid/  Emerging Infectious Disease

http://wwwnc.cdc.gov/eid/article/20/8/14-0590_article  Original web page at Emerging Infectious Diseases

In a molecular epidemiology study of hepatitis E virus (HEV) in dromedaries in Dubai, United Arab Emirates, HEV was detected in fecal samples from 3 camels. Complete genome sequencing of 2 strains showed >20% overall nucleotide difference to known HEVs. Comparative genomic and phylogenetic analyses revealed a previously unrecognized HEV genotype. Hepatitis E virus (HEV) belongs to the family Hepeviridae and genus Hepevirus. Among humans worldwide, HEV is the most common cause of acute viral hepatitis. The disease is generally self-limiting, but mortality rates are high among pregnant women and young infants. Chronic HEV infection is a problem for immunocompromised patients, such as those who have received a solid organ transplant and those with HIV infection. In addition to humans, HEV has been found in the other mammals: pigs, boar, deer, rodents, ferrets, rabbits, mongoose, bats, cattle, sheep, foxes, minks, and horses. Among the 4 known HEV genotypes, HEV1 and HEV2 infect only humans; whereas, HEV3 and HEV4 can infect humans, pigs, and other mammals. Human infections with HEV3 and HEV4 have been associated with consumption of raw or undercooked pork or game meat. Traditionally, HEV infection is mainly transmitted through water contaminated with infected feces. Since water supplies and sanitary infrastructures have been improved, animals have become a major source of human HEV infection. We detected HEV in fecal samples from dromedary camels in the Middle East.

As part of a molecular epidemiology study, 203 fecal samples from 203 adult dromedaries (Camelus dromedarius) were submitted to the Central Veterinary Research Laboratory in Dubai, United Arab Emirates, over a 7-month period (January–July 2013). RNA extraction and reverse transcription were performed, as described, to detect other positive-sense single-stranded RNA viruses. Screening for HEV was performed by PCR amplification of a 284-bp fragment of open reading frame (ORF) 2 in HEV; specific primers used were 5′-TTTATTCTCGTCCAGTCGTTTC-3′ and 5′-GTCAGTGGAGGACCCATATGT-3′, designed from sequence information from our metagenomic study. PCR was performed according to previously described conditions; annealing temperature were set at 50°C. DNA sequencing and quantitative real-time reverse transcription PCR were also performed as described. Using strategies we have reported for other positive-sense single-stranded RNA viruses, we performed complete-genome sequencing on 2 HEV-positive samples. Comparative genomic analysis was performed as described. Phylogenetic analysis was conducted in MrBayes5D version 3.1.2 (www.fifthdimension.jp/products/mrbayes5d/) by using an optimal substitution model with 1 million Markov chain Monte Carlo generations; sampling was conducted every 100 generations with a burn-in of 25,000. The substitution model was selected on the basis of the corrected Akaike information criterion by ProtTest version 2.4 (http://darwin.uvigo.es/software/prottest.htmlExternal Web Site Icon).

http://wwwnc.cdc.gov/eid/  Emerging Infectious Diseases

June 24, 2014

http://wwwnc.cdc.gov/eid/article/20/6/14-0140_article.htm Original web page at Emerging Infectious Diseases

Virologists Norbert Nowotny and Jolanta Kolodziejek from the Institute of Virology are investigating the transmission pathways of the MERS coronavirus. They found that viruses from infected humans and Arabian camels from the same geographical region have nearly identical RNA sequences. “This indicates transmission between animals and man. The process is referred to as zoonosis. With this knowledge we can specifically react to the spread of the virus. Vaccinations of camels are currently being discussed. We will thus be able to halt the spread of the virus,” said Nowotny. Virus RNA differs from region to region The scientists investigated nasal and conjunctival swabs, taken from 76 camels in Oman. In five camels they found the MERS coronavirus and compared its RNA with those of MERS coronavirus from Qatar and Egypt. The analysis showed that the viruses differ from region to region. “This means that there is no specific ‘camel MERS coronavirus strain’, but that one virus infects both, camels and humans,” says study coordinator Norbert Nowotny. Transmission pathway through nose and eyes.

Virus levels were surprisingly high in the nasal mucosa and conjunctiva of camels. Therefore the scientists presume that the transmission pathway from animals to humans most likely occurs through these contact sites, especially through nasal discharge. In man the virus causes severe pneumonia and renal failure while camels show no or very little symptoms (in some cases nasal discharge). So far all infections in humans have occurred in the Arabian Peninsula. However, some developed the disease after they returned to their native country, of whom eleven were from Europe. MERS coronavirus is also transmitted from one human to another, for instance in families, in the community, or through contact between patients and medical staff. MERS coronavirus is closely related to SARS coronavirus. SARS originated in China and claimed 800 lives worldwide in 2002 and 2003. “While the SARS coronavirus probably crossed the species barrier only once by passing from bats to humans, we may presume that the MERS coronavirus is being constantly transmitted from camels to humans,” explains Nowotny. The fact that MERS coronaviruses infect camels was shown by Nowotny and his colleagues in an earlier study, in which the scientists detected antibodies against the virus in the animals. The current genetic analysis of MERS coronarviruses permits more exact conclusions.

http://www.sciencedaily.com/  Science Daily

May 27, 2014

http://www.sciencedaily.com/releases/2014/05/140502081339.htm  Original webpage at Science Daily

The Middle East respiratory syndrome (MERS) first made world headlines when it was discovered in 2012. But new research shows that the responsible virus has probably been lurking in camels in Saudi   Arabia since 1992 or even longer—and that it is very common among the animals today. The study suggests that undiscovered human cases may also have occurred the past 2 decades. MERS is caused by a coronavirus, a class of pathogens high on scientists’ watch list because another member, the severe acute respiratory syndrome (SARS) virus, spread around the globe in 2003, killing more than 700 people. The syndrome has sickened 182 and killed 80 people so far, but it does not seem to transmit from one person to the next as easily as SARS did. That suggests most patients acquired the virus from animals. SARS probably originated in bats and spread to humans via civets. But scientists investigating MERS are finding more and more evidence pointing to camels as the source. Last summer, researchers reported finding antibodies against the virus—signaling either a past or a current infection—in the blood of retired racing camels from Oman, but not in cows, goats, or sheep. Since then, studies have also reported such antibodies in camels from Qatar, Jordan, and Egypt. One study found antibodies against MERS in camel blood samples kept in cold storage in the United Arab Emirates since 2003. At least one team also found antibodies in recent samples from camels in Saudi Arabia, the country that has seen the majority of human cases. But many scientists are frustrated by how little information has emerged from that crucial country so far.

Studying the MERS virus has been fraught with other difficulties as well. For instance, importing samples from camels and other animals into the United States is hampered by fears of foot-and-mouth disease, a highly infectious disease that infects cloven-hoofed animals such as cattle and pigs; meanwhile, research resources in the affected countries in the Middle East are limited. To address both problems, ColumbiaUniversity virologist Ian Lipkin built a mobile lab and sent it to Saudi   Arabia late last year. “Two thermal cyclers, a robotic nucleic acid extractor, tools for serology, all this equipment went over there in six Pelican cases,” he says. Together with Saudi colleagues, the researchers used the equipment to test 203 camels from different parts of Saudi   Arabia. They found antibodies against the MERS virus in 150 of them. They also discovered the virus’s RNA in rectal or nasal swabs from 51 animals, a sign that they were harboring the virus at the time of testing. Viral sequences closely matched those from human patients. Because the nasal swabs yielded the most virus, the most likely scenario is airborne transmission of the pathogen, the authors write in mBio today. The researchers also looked at more than 100 camel serum samples from an archive going back to 1992 and found antibodies against MERS in almost all of them. “This virus has clearly been in camels since at least 1992,” Lipkin says.

The paper adds to the growing evidence on the animal reservoir of MERS, says Marion Koopmans, an infectious disease researcher at the National Institute of Public Health and the Environment in Bilthoven, the Netherlands. “It is now undisputable that these viruses circulate among dromedary camels,” she writes in an e-mail. Bart Haagmans, a virologist at Erasmus MC in Rotterdam, the Netherlands, says he is surprised that viral RNA could be found in so many of the animals. “You don’t expect to find a virus for a respiratory infection in almost one in four animals,” he says. It suggests that the virus knows how to maintain itself in the camel population very well. It’s not clear whether the virus actually makes camels sick, but it seems to infect many camels at a young age, Haagmans says. Most scientists agree that studies looking at infected camels over time are needed to find out how long they can harbor virus. Finding antibodies in 22-year-old samples raises the question of why the first known human patients date from 2012, Koopmans says. “Have human cases been missed before, or has something changed in the camel viruses that makes them transmit to humans?” To resolve that question, scientists would have to look at more old samples from Middle Eastern patients with respiratory illness—and those aren’t available, she writes. Whether MERS has been infecting humans for 2 decades or 2 years, there is still a real danger that it will start spreading between people more rapidly and trigger a pandemic, says Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, Twin Cities. “We’re now at the second level of concern,” he says, because MERS is not just a dangerous virus in animals but is spilling over into the human population again and again. “The third level could happen tomorrow.”

http://news.sciencemag.org/sciencenow  ScienceNow March 2014-03-05

http://news.sciencemag.org/health/2014/02/deadly-mers-virus-has-infected-camels-least-1992  Original web page at ScienceNow

Replicative capacity of Middle East respiratory syndrome coronavirus (MERS-CoV) was assessed in cell lines derived from livestock and peridomestic small mammals on the Arabian Peninsula. Only cell lines originating from goats and camels showed efficient replication of MERS-CoV. These results provide direction in the search for the intermediate host of MERS-CoV. Coronaviruses (CoV) in the genera Alphacoronavirus and Betacoronavirus (order Nidovirales, family Coronaviridae, subfamily Coronavirinae) infect a broad range of mammals, including humans. The human CoVs (HCoVs) HCoV-HKU1, HCoV-229E, HCoV-NL63, and HCoV-OC43 typically cause mild to moderate respiratory tract infection; however, the disease course can be more severe in a minority of patients. In 2002–2003, an epidemic of severe lower respiratory tract infection with a case-fatality rate of ≈10% was caused by severe acute respiratory syndrome (SARS)–CoV. In 2012, another CoV associated with severe respiratory disease emerged on the Arabian Peninsula and was termed Middle East respiratory syndrome (MERS)–CoV.

Both SARS-CoV and MERS-CoV are zoonotic viruses, and their presumed origin is in bats. SARS-related CoVs were identified in Rhinolophus spp. bats in China and Europe, and MERS-related CoVs were found in Pipistrellus bats in Europe and in Neoromicia bats in South Africa. As with SARS-CoV, it is expected that MERS-CoV might be transmitted to humans by an intermediate animal host, and neutralizing antibodies against MERS-CoV have been found in Arabian camels originating from Oman, Spain, and Egypt. We investigated replication of MERS-CoV in cell lines of the most abundant mammalian livestock species and representative peridomestic small mammals on the Arabian Peninsula. To estimate MERS-CoV permissiveness of cell cultures derived from these animals, we compared MERS-CoV replication and infectious virus production with that in bat- and primate-derived cells known to be permissive for MERS-CoV. The MERS-CoV receptor dipeptidyl peptidase 4 (DPP-4) is expressed in epithelial cells of the lung and kidney, and patients with MERS-CoV consistently show severe involvement of both organs; thus, we focused on lung and kidney cells in potential animal hosts.

Emerging Infectious Diseases
January 21, 2014

Original web page at Emerging Infectious Diseases

Possible infection with the MERS coronavirus, or a closely related virus, has been detected in camels. A year on from the first reported human case of infection with Middle East respiratory syndrome coronavirus (MERS-CoV), the world still has few answers to the most pressing question from a public-health perspective: what is the source of the steady stream of new cases? Only with this information can the outbreak be controlled. There have so far been 114 confirmed cases of MERS-CoV infection, including 54 deaths, with another 34 suspected cases. All originated in the Arabian Peninsula, with most in Saudi Arabia and others in Jordan, Qatar and the United Arab Emirates (UAE). Imported cases have occurred in the United Kingdom, France, Italy and Tunisia. The virus is thought to be an animal virus that sporadically jumps to people — there are no signs yet that it can spread easily between humans, although limited spread between people in close contact has been seen.

But a lack of epidemiological studies means that the source of the virus is still unknown. This is “absolutely unacceptable”, says Michael Osterholm, head of the University of Minnesota’s Center for Infectious Disease Research and Policy in Minneapolis. Affected countries have to some extent lacked a sense of urgency, agrees Jean-Claude Manuguerra, head of the Laboratory for Urgent Response to Biological Threats at the Pasteur Institute in Paris. They have also tended to consider it a sovereign issue that is the business of national authorities, not outsiders, he adds. Manuguerra was one of 13 international health experts invited by the Saudi Arabian government and the World Health Organization (WHO) in Geneva, Switzerland, to visit the country in June as part of a joint mission to assess the situation and recommend measures to control the outbreak. He contrasts the lack of progress on MERS epidemiology with China’s rapid and robust response following the report in March of the first human cases of a new H7N9 avian influenza virus, which quickly identified live-bird markets as the main route of human infections and moved swiftly to shut them down. To identify a source of infection, patients must be questioned in detail about their recent activities, such as whether they visited animal markets or farms, or ate certain foods, to find patterns and leads for investigation. But the joint Saudi–WHO mission concluded that such work has not been detailed enough to accomplish this.

Also insufficient, the mission said, were efforts to look for the virus in animal populations, which would enable transmission routes to humans to be shut down. Bats are likely to have been the original source: the genome sequence of the MERS virus is closest to that of other bat corona­viruses. Since this discovery, Saudi Arabia has twice invited a team led by Ian Lipkin, a virologist at Columbia University in New York, to sample bat tissue and faeces, and in August the team published a partial sequence that seems to match that of MERS1 (see Nature http://doi.org/ntk; 2013). But direct contact with bats is unlikely to explain the human cases, and scientists suspect that the virus has infected other animals that are more likely to come into contact with people. Some say they are baffled that affected countries have not carried out large-scale sampling of animals to look for the virus. Ziad Memish, Saudi Arabia’s deputy minister of health, says that his country has been waiting for advice about testing from the Rome-based United Nations Food and Agriculture Organization (FAO) and the World Organisation for Animal Health in Paris.

Juan Lubroth, the FAO’s chief veterinary officer, says that its first expert mission to assess possible animal sources left last weekend for Saudi Arabia and the UAE. There will be several more, he adds, and the FAO hopes to work with national authorities to start epidemiological studies within months. A tantalizing clue to a possible animal source comes from two studies on camels. Both found antibodies to MERS or a closely related virus in camels in neighbouring countries to those affected, indicating past infection. Neither found live virus in the animals, however. “It is possible that such a virus is ubiquitous, but from time to time is undergoing crucial mutations that allow limited cross-species jumps from the intermediate host to humans,” says Malik Peiris, a virologist at the University of Hong Kong and a co-author of one of the studies. That was the scenario with the exotic coronavirus SARS that emerged in Hong Kong in late 2002 and evolved to become a virus that spread easily between humans, killing almost 800 people before dying out in July 2003. With millions soon to be on the move for the hajj, the annual pilgrimage to Mecca in mid-October, the Saudi authorities are on high alert for suspected cases of MERS, and will no doubt be hoping that MERS is not the next SARS.

Nature
October 1, 2013

Original web page at Nature