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Common cold viruses originated in camels, just like MERS

There are four globally endemic human coronaviruses which, together with the better known rhinoviruses, are responsible for causing common colds. Usually, infections with these viruses are harmless to humans. DZIF Professor Christian Drosten, Institute of Virology at the University Hospital of Bonn, and his research team have now found the source of “HCoV-229E,” one of the four common cold coronaviruses — it also originates from camels, just like the dreaded MERS virus.

The Middle East respiratory syndrome (MERS) coronavirus was identified in humans for the first time in 2012. It causes severe respiratory tract infections that are often fatal. Dromedaries were confirmed to be its animal source some time ago.

“In our MERS investigations we examined about 1,000 camels for coronaviruses and were surprised to find pathogens that are related to ‘HCoV-229E’, the human common cold virus, in almost six percent of the cases,” says Drosten. Further comparative molecular genetic analysis of common cold viruses in bats, humans and dromedaries suggests that this common cold virus was actually transmitted from camels to humans. Common cold virus evolution could provide a scenario for MERS emergence

Drosten and his team isolated live camel common cold viruses and discovered that these could principally also enter human cells — via the same receptor used by the common cold virus “HCoV-229E.” However, the human immune system is able to defend itself against the camel viruses, just as it can against common cold viruses. Furthermore, tests with human serum and animal common cold viruses showed that there is no immediate risk of an epidemic in humans, because largest part of the human population already has immunity, owing to the widespread immunity against the common cold virus HCoV-229E.

So is this the all-clear for MERS viruses too? “The MERS virus is a strange pathogen: smaller, regionally restricted outbreaks, for example in hospitals, keep occurring. Fortunately, the virus has not adapted well enough to humans, and has consequently been unable to spread globally up to now,” says Drosten. The results of the current investigations on predecessors of the human HCoV-229E virus in camels depict a situation that is similar to the current situation with MERS. These predecessor viruses are also not optimally adapted to humans.

The global spread of HCoV-229E through human-to-human transmission, which is highly likely to have occurred during a past pandemic, gives rise to concern. “Our current study gives us a warning sign regarding the risk of a MERS pandemic — because MERS could perhaps do what HCoV-229E did.” So there is need for action: DZIF researchers are working intensively on researching a vaccine against MERS; it will go into clinical testing early next year.

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

https://www.sciencedaily.com/releases/2016/08/160818093438.htm  Original web page at Science Daily

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Origin of dromedary camel domestication discovered

The dromedary, the one-humped Arabian camel, plays an important role in the countries of North Africa. For thousands of years, the people of North Africa and Asia have used the animal for the transportation of people and goods. It was fundamental to the development of human societies in inhospitable environments. Dromedaries are the largest domesticated livestock species.

“Many open questions remain with regard to the dromedary’s domestication and evolutionary history,” explains Pamela Burger from the Research Institute of Wildlife Ecology at Vetmeduni Vienna. “We have managed to turn the wild dromedary into a domesticate, but we don’t know how and where domestication began and what effect it has had on today’s animals.”

During the domestication process, people usually breed the animals by selecting those parts of the genotype that bring the most benefit. The team around Burger has shown for the first time that this was not the case with the dromedary. Dromedaries exhibit an enormous genetic diversity despite the fact that breeding usually results in a low genetic diversity. This makes dromedaries different from other animals domesticated through breeding.

Burger and her team collected samples from nearly 1,100 extant dromedaries and compared these with archaeological samples from wild and early-domesticated animals. Using DNA analysis, the researchers determined that the dromedary’s genetic diversity is directly related to its use as a transport animal. The forth-and-back movement of the caravans brings different dromedary populations in contact with each other. This leads to a regular gene flow and the maintenance of the genetic diversity. An isolated group is rare. Only one population in East Africa deviated from the genetic diversity of the other dromedaries. This group, however, has been isolated for some time due to geographic obstacles and cultural barriers.

The regular gene flow reflects a genetic diversity that is usually found only in wild animals. But it makes it difficult to determine the wild form from which today’s dromedary is descended and, therefore, where it was domesticated.

Burger and her team succeeded in answering this question. The group of researchers analysed up to 7,000-year-old DNA from bones of wild and early-domesticated dromedaries and compared the samples with the genetic profiles of modern dromedary populations from around the world. For the first time, it was possible to identify the Southeast Arabian Peninsula as the region of first domestication. “Our results appear to confirm that the first domestication of wild dromedaries occurred on the southeast coast. This was followed by repeated breeding of wild dromedaries with the early-domesticated populations,” Burger explains. The wild ancestor of today’s dromedary had a geographically limited range and went extinct around 2,000 years after the first domestication.

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

https://www.sciencedaily.com/releases/2016/05/160509191839.htm  Original web page at Science Daily

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* MERS virus: Drying out the reservoir

A German-Dutch team has succeeded in immunizing dromedaries against the MERS virus. As the camels appear to be the major reservoir of the virus, the vaccine should also reduce the risk of future outbreaks of the disease in humans.

The recently discovered coronavirus now referred to as MERS (for Middle East Respiratory Syndrome) causes an infectious respiratory disease in humans, which can be fatal. The virus is thought to be transmitted to humans primarily via contact with dromedary camels. Now researchers led by virologist Gerd Sutter at Ludwig-Maximilians-Univeritaet (LMU) in Munich, in collaboration with teams led by Professor Bart L. Haagmans of the Erasmus Medical Center (MC) in Rotterdam and Professor Albert Osterhaus of University of Veterinary Medicine Hannover, Foundation (TiHo), have successfully tested a candidate vaccine against MERS, in camels.” We have been able to show, for the first time, that our vaccine can significantly reduce the virus load in infected camels,” says Sutter. The results of the trial appear in the latest issue of the journal Science.

The new vaccine, MVA-MERS-S, was developed by Sutter and his team two years ago. In cooperation with researchers based at Philips University in Marburg and the team in Rotterdam, he introduced a gene for the so-called spike protein of MERS into the genome of a weakened strain of poxvirus (MVA). The resulting modified poxvirus particles expressed the MERS protein on the surface of infected cells, and these engineered viruses form the basis of the new vaccine. Several preliminary data over the past two years have confirmed the immunogenicity and efficacy of MVA-MERS-S in mice. The scientists now describe the outcome of the first direct test of the vaccine in camels.

The MERS virus was first identified in Saudi Arabia in 2012. To date, some 1400 cases of MERS have been reported, of which one-third proved fatal. Its primary hosts, however, are dromedary camels, as revealed by the detection of antiviral antibodies and the presence of MERS particles in the nasal cavity in infected animals. Although camels infected with the virus show relatively mild symptoms, all the evidence suggests that they can transmit the pathogen to humans, who can subsequently pass it on to others. Hence, vaccination of camels against MERS virus is an obvious method of choice for the prevention of human infections. Successful immunization would deprive the virus of its primary host and break the chain of transmission, effectively minimizing the risk of future MERS epidemics in human populations.

But the vaccine from Sutter’s laboratory actually turns out to another advantage: “Immunization with MVA-MERS-S simultaneously protects camels from camelpox, a disease similar to smallpox in humans — which can be life-threatening in dromedaries,” Bart L. Haagmans of the Erasmus Medical Center explains.

In camels infected with the MERS virus, symptoms of disease are confined to the upper respiratory tract. In the new study, the researchers infected a total of 8 camels. Half of these had been immunized, both intranasally and intramuscularly, with MVA-MERS-S three weeks prior to exposure to the virus. “In this group of animals, the vaccine had induced the development of sufficient amounts of antibodies to inhibit viral multiplication and prevent the appearance of disease symptoms upon infection,” says Dr. Asisa Volz, a member of Prof. Sutter’s group. In addition, anti-MERS antibodies were detected in both the nasal mucosa and in the bloodstream of immunized animals. The controls, on the other hand, which were injected with poxviruses particles lacking the S protein, exhibited the typical runny nose, and infectious virus was readily detectable in nasal secretions. “Our results clearly show that vaccination with MVA-MERS-S markedly reduces the numbers of viruses present in the nasal epithelia of camels,” says Albert Osterhaus of University of Veterinary Medicine Hannover.

MVA-MERS-S can, of course, also be used to immunize humans. Indeed, thanks to the tests carried out so far, the vaccine already meets many of the most important preconditions that must be fulfilled prior to its use in clinical trials in humans. Gerd Sutter is currently leading a project entitled “GMP manufacture and Phase I clinical investigation of MVA-MERS-S, an experimental prophylactic vaccine against the Middle East Respiratory Virus Syndrome” at the German Center for Infection Research, which is designed to set the scene for the first such tests of the vaccine in humans.

So far, there are no candidate vaccines available that could be used in the event of a large-scale epidemic. Only a few months ago, in the early summer of 2015, more than 180 people were infected with MERS in South Korea. The origin of the outbreak was traced to a single carrier, who had recently returned from the Middle East. All confirmed infections in humans have so far been linked, directly or indirectly, to that part of the world, hence the name Middle East Respiratory Syndrome Coronavirus (MERS-CoV) for the pathogen responsible. Three cases of MERS have been recorded in Germany. All three patients had recently visited Saudi Arabia, and had contracted the disease there.

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

http://www.sciencedaily.com/releases/2015/12/151218085630.htm  Original web page at Science Daily

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* How Australia’s Outback got one million feral camels: Camels culled on large scale

A new study has shed light on how an estimated one million-strong population of wild camels thriving in Australia’s remote outback have become reviled as pests and culled on a large scale. Camels played a significant role in the establishment of Australia’s modern infrastructure, but rapidly lost their economic value in the early part of the 20th century and were either shot or released into the outback. A new study by a University of Exeter researcher has shed light on how an estimated one million-strong population of wild camels thriving in Australia’s remote outback have become reviled as pests and culled on a large scale. Sarah Crowley, of the Environment and Sustainability Institute at the University of Exeter’s Penryn Campus, explored the history of the camel in Australia, from their historic role helping to create the country’s infrastructure through to their current status as unwelcome “invader.” The deserts of the Australian outback are a notoriously inhospitable environment where few species can survive. But the dromedary camel (Camelus dromedarius) prospers where others perish, eating 80% of native plant species and obtaining much of their water through ingesting this vegetation. Yet for numerous Australians, particularly ranchers, conservation managers, and increasingly local and national governments, camels are perceived as pests and extreme measures — including shooting them with rifles from helicopters — are being taken to reduce their population. In her article, published in the journal Anthrozoös, Crowley proposes that today’s Australian camels exemplify the idea of “animals out of place” and discusses how they have come to inhabit this precarious position. She said: “Reports estimate there are upwards of a million free-ranging camels in Australia and predict that this number could double every eight years. As their population burgeons, camels encroach more frequently upon human settlements and agricultural lands, raising their media profile and increasing local animosity toward them.”

The camel was first brought to Australia in the 1800s when the country was in the midst of a flurry of colonial activity. The animals were recognized by pioneers as the most appropriate mode of transport for the challenging environment because they require significantly less water, feed on a wider variety of vegetation, and are capable of carrying heavier loads than horses and donkeys. Camels therefore played a significant role in the establishment of Australia’s modern infrastructure, including the laying of the Darwin-Adelaide Overland Telegraph Line and the construction of the Transnational Railway. Once this infrastructure was in place, however, and motorized transport became increasingly widespread, camels were no longer indispensable. In the early part of the 20th century they rapidly lost their economic value and their displaced handlers either shot their wards or released them into the outback where, quite discreetly, they thrived. It was not until the 1980s that surveys hinted at the true extent of their numbers, and only in 2001 that reports of damage caused by camels were brought to the general populace. Camels are not the most dainty of creatures. Dromedaries are on average six feet tall at the shoulder, rendering cattle fencing no particular obstacle to their movement. By some accounts, camels may not even see small fences and consequently walk straight through them. Groups of camels arriving on agricultural properties and settlements in Australia, normally in times of severe drought, can also cause significant damage in their search for water. In 2009, a large-scale culling operation began. There were objections from animal welfare groups and some landowners who were concerned that the method of culling from helicopters, leaving the bodies to waste, is inhumane. Most objectors, however, were primarily concerned that culling is economically wasteful and felt that the camels should be mustered for slaughter or export.

There are also concerns regarding the global environment, as camels may contribute to the desertification of the Australian landscape. They are also ruminants and thus produce methane, adding to Australia’s carbon emissions. Crowley does not question the accuracy or significance of this, but points out that the environmental impacts of even 1,000,000 feral camels pales in comparison to that of the 28,500,000 cattle currently residing in the country. Still, when dust storms gathered over Sydney in 2009, media reports implied that the camel was the culprit. Camels have in recent times been referred to in Australia as “humped pests,” “a plague,” a “real danger” and “menacing,” and their actions described as “ravaging” and “marauding.” Crowley added: “These terms show how camels have suddenly been attributed agency — their crossing of acceptable human boundaries is somehow deemed purposeful and rebellious. These accusations lie in stark contrast to the praise laid upon those dromedaries who assisted colonists in the exploration and establishment of modern Australia, and highlight how temporal changes in culture — specifically, shifting economic and environmental values — have affected human interpretations of the presence, purpose, and even behavior of Australian camels.”

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

May 13, 2014

http://www.sciencedaily.com/releases/2014/04/140423101902.htm  Original web page at Science Daily