The camel, at the origin of the MERS coronavirus, is also responsible for the expansion of a strain responsible for 10 to 15% of colds.
Severe and often fatal respiratory infections: this is the best-known face of the coronavirus. SARS and MERS are the most feared strains. But this “crown virus” is also the source of less severe infections.
10 to 15% of colds are attributed to a human strain. She still shares a point in common with her cousin from the Middle East: the human coronavirus 229E also comes from the camel, according to a German study published in PNAS.
An endemic strain
In total, four strains of the coronavirus are endemic in humans and cause colds. Among them, HCoV-229E. Described for the first time in 1967 in humans, it is also found in an animal often frequented in Africa and on the Arabian Peninsula: the camel. To reach this conclusion, researchers at the University of Bonn (Germany) analyzed 1,033 animals infected with the Middle East respiratory coronavirus (MERS-CoV).
These specimens also carried coronaviruses linked to their human strain, the study reveals. In 5.6% of them, similarities with the virus that causes the common cold in humans emerged. These are receptors common to both strains. A genetic comparison with other carrier species, including the bat, confirmed this ancient association.
A vaccine track
Like MERS-CoV, the human coronavirus 229E therefore comes from the camel. With one difference: the second strain, initially poorly adapted to a human host, ended up becoming endemic. A pandemic is probably responsible for this expansion. “The MERS virus is a strange pathogen: small and restricted outbreaks continue to emerge, in hospitals for example. Fortunately, the virus has not adapted well to humans, and remains unable to spread globally for the moment ”, tempers Christian Drosten, co-author of the study.
The researchers, however, are cautious. First, the human immune system has good defenses against viruses from camels. This probably explains why colds are of low magnitude. More importantly, it is difficult to predict whether MERS-CoV will evolve like its more innocuous cousin. This possibility should lead to the greatest precaution, believes the team. A vaccine is also in development. A team from the US National Institute of Allergy and Infectious Diseases (NIAID) uses a protein that the virus uses to enter cells to infect them. Clinical trials should be started by 2017.
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