Arabian one-humped camels in Oman may be transmitting the new coronavirus that’s killed 46 people, according to a study published in the Lancet Infectious Diseases medical journal.
Neutralizing antibodies specific to the Middle East respiratory syndrome coronavirus, or MERS-CoV, or a very similar virus, were found in all 50 serum samples taken from Arabian dromedary camels in Oman, according to the study, led by Chantal Reusken of the National Institute for Public Health and the Environment in Bilthoven, the Netherlands.
While a study published last month found that South African bats may be the source of the virus, researchers suspect other animals may be intermediate hosts, because there is limited human contact with bats. A team of scientists gathered 349 blood serum samples from livestock animals including camels, cows, sheep and goats from Oman, the Netherlands, Spain and Chile.
“These new results suggest that dromedary camels may be one reservoir of the virus that is causing MERS-CoV in humans,” the authors said in a statement. “Targeted studies are needed to confirm our findings and their possible relevance in relation to the human cases.”
In the Middle East, camels are raced and used for their meat and milk, so there are different types of contact with humans that could lead to transmission of a virus, they said.
“The most critical question remains to be answered, that is, the type of human exposures that result in infection,” the World Health Organization said today in updated list of frequently asked questions about the virus. “Most human cases do not have a history of direct contact with camels; if camels or other animals are the source, the route of transmission to humans may be indirect.”
Lower levels of the coronavirus-specific antibodies were also found in 14 percent of samples taken from dromedaries from the Canary Islands of Spain.
While camels on the Canary Islands were originally imported in the 15th century from the Horn of Africa, this practice is now banned because of the risk of foot-and-mouth disease. Exports into the Middle East from Africa still continue in large numbers, and this difference in turnover could be affecting the virus epidemiology, the researchers said.
It’s unclear whether the detection of antibodies in both Spain and Oman is a result of unrelated cross-species transmission or because the virus has been circulating in camels for a long time, Emmie de Wit and Vincent Munster of the National Institute of Allergy and Infectious Diseases in Hamilton, Montana, said in a comment accompanying the article.
“Although the study by Reusken and colleagues leaves many questions unanswered, it is an important step to a more comprehensive understanding of the emergence of coronavirus,” they said.
It’s premature to rule out the possibility that other animals might serve as a reservoir or host for the virus, the WHO said.
“Because neither the source of the virus nor the mode of transmission is known, it is not possible to give specific advice on prevention of infection,” the Geneva-based agency said. “Contact with any obviously sick animals should be avoided.”