Researchers believe they have identified the source of the deadly Middle East respiratory syndrome (MERS) outbreak: one-humped camels that are used in Saudi Arabia for meat, milk, transportation, and racing. The preliminary study revealed test results that confirmed a virus, similar to MERS, is circulating in the animals. The virus is either MERS or a similar respiratory case, bringing researchers one step closer to identifying the route of MERS' initial spread.

The respiratory illness, which has plagued 74 people in Saudi Arabia out of the 94 worldwide cases, has been a mystery for doctors ever since its first signs arrived in September 2012. Not even a year later, 46 people have died from MERS, a cousin to severe acute respiratory syndrome (SARS), another deadly respiratory virus that spread throughout the world 10 years ago, claiming nearly 800 lives and infecting over 8,000.

Recently, health officials announced the unlikelihood that MERS will infect the world on the same scale as SARS did; however, it’s been almost a year and researchers are still scrambling to find the cause of the virus. The 46 deaths loom over researchers’ heads as they worry that the spread of infection will only worsen, but before they pin the blame on camels, they say more research is necessary.

MERS is known to cause fever and pneumonia-like symptoms, and has subsequently claimed lives in France, Italy, Jordan, Qatar, Saudi Arabia, Tunisia, the United Kingdom, and the United Arab Emirates.

An international team of doctors and researchers is currently investigating blood samples taken from 160 livestock animals from different countries, which include not only the primary suspect — camels — but also sheep, goats, and cows.

“We did find antibodies that we think are specific for the MERS coronavirus or a virus that looks very similar to the MERS coronavirus in dromedary camels,” Professor Marion Koopmans, from the National Institute of Public Health and the Environment and Erasmus University, told BBC News.

Experts are relieved to have found the first possible indication of the virus’s source. After all, there are very few things known about the virus, except that it travels with ease through hospitals and from person to person; but now with the known possibility of animal contagion, doctors have a whole new set of characteristics to draw out.

In the case of SARS, in 2005, two years after its initial breakout, two teams of researchers discovered large reservoirs of SARS-infected Chinese horseshoe bats. The disease transfer occurred when humans captured the bats and brought them to markets in southern China — the location of the first breakout.

Viruses evolve rapidly and constantly, changing their sequence of genetic information, which is why they are able to move from one animal to another, and in this case, to humans. This could be a similar situation in the case of MERS, especially since it's a respiratory virus that has followed the symptoms and movements of SARS.

“What this study has shown is antibodies in the camels, that means the camels have been infected at some point in time and that produced antibodies,” Tarik Jasarevic, World Health Organization spokesman, said at a news briefing in Geneva on Friday.

“Finding the [MERS] virus is like finding a needle in a haystack, but finding the antibodies at least gives you an indication of where to look,” Koopmans said. “What this tells us is that there’s something circulating in camels that looks darned similar to MERS.”

Source: Reusken CB, Haagmans BL, Muller MA, et al. Middle East respiratory syndrome coronavirus neutralising serum antibodies in dromedary camels: a comparative serological study. The Lancet. 2013.