DOHA: Studies conducted on 14 camels in a farm in Qatar where three camels were found infected with MERS (Middle East Respiratory Syndrome) recently have revealed that all the dromedary had developed antibodies to MERS suggesting the virus might have been circulating for some time.
The study, published in the Lancet Infectious Diseases journal yesterday, also revealed that the gene sequences in the camels were very similar, although not identical, to those identified in the two people who were infected with the virus from the same site, Reuters reported yesterday.
Researchers from the Netherlands and Qatar used gene-sequencing techniques to show that three dromedary, or one-humped camels, on the farm where two people had contracted the MERS coronavirus (CoV) were also infected. But they cautioned it was too early to say whether the camels were definitely the source of the two human cases — in a 61-year-old man and then in a 23-year-old male employee of the farm — and said more research was needed.
“This is definitive proof that camels can be infected with MERS-CoV, but based on the current data we cannot conclude whether the humans on the farm were infected by the camels or vice versa,” said Bart Haagmans of Rotterdam’s Erasmus Medical Centre, who led the study with other Dutch and Qatari scientists.
He said a further possibility was that humans and camels could have been infected “from a third as yet unknown source”.
“The big unknown is the exact timing of infections, in the persons and the camels,” he added. Both men have recovered.
Scientists around the world have been searching for the animal source, or reservoir, of MERS virus infections since the first human cases were confirmed in September 2012.
Globally to date, World Health Organisation (WHO) says there have been 163 laboratory-confirmed human cases of MERS, including 71 deaths. It is also aware of around a dozen other probable but unconfirmed MERS cases in people.
Cases have so far been reported in Saudi Arabia, Qatar, Kuwait, Jordan, the UAE, Oman, Tunisia, France, Germany, Spain, Italy and Britain. In the Qatar study, researchers collected clinical samples, including nasal, blood and rectal swabs and stool samples from 14 dromedary camels living in a barn in Qatar where in the previous week, the 61-year-old owner of the barn had been diagnosed with MERS infection.
The samples were sent to laboratories in the Netherlands for genetic and antibody testing, which confirmed the presence of MERS in three of the animals.
Researchers noted that all 14 camels had antibodies to MERS, suggesting the virus might have been circulating among the animals for some time, allowing most of them to build up immune protection against infection.
Since they were not able to say definitely whether the virus had passed from the camels to humans, or the other way, the researchers stressed they could not rule out that other common livestock species, like cattle, sheep and goats, or other animals, may be involved in the spread of MERS. To help find more answers, they said, researchers should aim to plot detailed case histories of all human cases of MERS, including any exposure to animals or animal products as well as links with other infected people. The Peninsula
