Camels Have Been Carrying Around a Deadly, Contagious Virus For At Least Twice As Long As Anyone Realized

Over the past twenty years, cases of the MERS virus might have gone undetected in infected humans

Photo: Nick Leonard

Middle East respiratory syndrome (MERS) first turned up in 2012 in scattered cases in Saudi Arabia, and not long after, cases started emerging in six more Middle Eastern countries and in Europe. This was a dangerous virus—around half of those infected died—but it wasn't clear where it was coming from.

Scientists suspected that, similar to ebola in bats and yellow fever in chimpanzees, MERS was living in another species that could transmit the virus to humans. They began searching for an animal carrying the virus. Bats were a possibility. Camels, too.

And although it's possible the camels contracted MERS from bats, researchers are now almost certain that it's camels that are responsible for transmitting the disease to people. What's more, a new study shows that this virus is not all that new. Researchers previously found MERS antibodies in camel samples stored from 2003, but this study confirms that the virus has been lurking in camels since at least 1992. 

Here's ScienceNow with the finding

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," [epidemiologist Ian] 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.

It seems the virus is quite common in camels, too. In recent tests of around 200 camels in Saudi Arabia, ScienceNOW says, 150 turned up positive for MERS antibodies. It is possible that the virus only recently evolved the ability to jump from camels to humans. Or it could be that past cases of MERS slipped by, written off as a cold or other disease. 

For camels, a case of MERS might be akin to something like chicken pox or another childhood illness, the New York Times reports. The animals seem to catch it when they are young and develop an immunity to it. After they have survived the illness and developed anitbodies, they become much less of a contagion threat for people, if at all. 

MERS is still a relatively rare disease and is only contagious upon close contact with an infected person or animal. The fear, of course, is that the virus might evolve to become more contagious or more transmissible.

As the Times reports, the next step might be to develop a vaccine for camels and quarantine those that are determined to be currently infected. That requires a quick test, however. “It would be very difficult to know if they were ill, since these are creatures that slobber a great deal,” Lipkin told the Times

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