The deadly MERS virus sweeping the Middle East, especially Saudi Arabia, could have originated in the one-humped dromedary camel of Arabia, scientists believe.
So far there have been 94 confirmed cases of Middle East Respiratory Syndrome cornonavirus (MERS-CoV), and 46 deaths - with Saudi Arabia as the country most affected.
Researchers gathered 349 blood serum samples from a variety of livestock animals, including dromedary camels, cows, sheep, and goats, from different countries, including Oman, the Netherlands, Spain, and Chile.
They analysed the blood serum samples for the presence of antibodies specific to MERS-CoV, as well as antibodies reactive to SARS coronavirus, and another strain of coronavirus labelled HCoV-OC43, which can also infect humans.
The researchers found no evidence of cross-reactivity between antibodies for MERS-CoV and those for SARS or HCoV-OC43.
No MERS-CoV antibodies were found in blood serum taken from 160 cattle, sheep, and goats, researchers said.
However, antibodies specific to MERS-CoV were found in all fifty serum samples taken from dromedary camels in Oman.
The Oman samples originated from a number of different locations in the country, suggesting that MERS-CoV, or a very similar virus, is circulating widely in dromedary camels in the region, researchers said.
Lower levels of MERS-CoV-specific antibodies were also found in 14 per cent (15) of serum samples taken from two herds of dromedaries (105 camels in total) from the Canary Islands, not previously known to be a location where MERS-CoV is circulating.
"The dromedary camels that we tested from the Middle East (Oman) were more often positive and had much higher levels of antibodies to MERS-CoV than the dromedary camels from Spain, researchers led by Dr Chantal Reusken, of the National Institute for Public Health and the Environment in Bilthoven, the Netherlands, said.
"The best way to explain this is that there is a MERS-CoV-like virus circulating in dromedary camels, but that the behaviour of this virus in the Middle East is somehow different to that in Spain," researchers said.
"As new human cases of MERS-CoV continue to emerge, without any clues about the sources of infection except for people who caught it from other patients, these new results suggest that dromedary camels may be one reservoir of the virus that is causing MERS-CoV in humans," said researchers.
Dromedary camels are a popular animal species in the Middle East, where they are used for racing, and also for meat and milk, so there are different types of contact of humans with these animals that could lead to transmission of a virus, they said.
