A case of camel-to-human infection of Middle East respiratory syndrome (MERS) has been identified, confirming the theory that the pack animals are the source of the deadly virus.

Back in February, experts revealed the results of an extensive investigation of domesticated animals in Saudi Arabia, looking for potential animal origins of the MERS virus.

According to a study published in mBio, genetic testing of domestic sheep and goats common to the region showed no signs of the virus. However, an estimated three fourths of all dromedary camels in Saudi Arabia were found to be carrying the same strain of MERS virus that is currently infecting the country's human population. In some provinces, 100 percent of the camels tested positive for MERS.

This led researchers to conclude that MERS - which expresses itself more harmlessly in camels - may have been circulating among the pack animals for decades before finally transferring it to humans. However, the researchers were unable to identify how exactly the virus spreads from camel to human, as they were unable to find any real life examples.

Now, according to a study published in the New England Journal of Medicine, they have found such a case.

Dr. Marc Siegel, an infectious disease expert, told Health Day that this study confirms what has long been suspected since February and even before.

"Camel-to-human transmission started this thing," he said, calling camels "the Typhoid Mary of MERS."

According to the study, a 44-year-old Saudi man was admitted to King Abdulaziz University Hospital in Jeddah, Saudi Arabia last November, where it was revealed he had MERS. A comprehensive investigation proved that the man has spent considerable time with his nine camels before becoming ill.

Further laboratory testing showed that the man, who died of his infection, had been host of the very same virus with the very same genetic markers that all nine of his camels had.

But, while the study confirmed camel-to-human transmission is possible, it does little to explain how it occurs.

Both the mBio study and a later WHO report have indicated that the MERS virus does not spread via nostril expulsion, and is far more likely to have spread to humans through infected camel meat or milk.

Still, this confirmation does help support recent requests from the Saudi Arabian Ministry of Health that citizens only handle their camels with masks and gloves as a precautionary measure.

In defiance of this request, some Saudi's have begun kissing their camels - a risky but likely harmless act.