Should we be worried about this new crossing of the inter-species barrier by a virus? The announcement, Saturday, February 20, by the boss of the Russian health agency Rospotrebnadzor, Anna Popova, of seven cases of H5N8 avian influenza in employees of a poultry factory in southern Russia had the effect of a bomb.
If the information is confirmed, this “Would be the first time that H5N8 infects humans », recognized the World Health Organization (WHO). The organization judges the discovery ” important “, but she is also cautious. “We are in discussion with the (Russian) authorities to gather more information and assess the impact of this event on public health”, she said.
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For now, this new variant of the virus is believed to be transmitted only from birds to humans, and not from human to human. The sick ones “Feel good”, assured Anne Popova without detailing the clinical symptoms. But Russia takes the problem very seriously, and intends to take advantage of this early detection of the mutation to give « the whole world time to prepare (…) in the event that this virus becomes more pathogenic and more dangerous for humans, and acquires the ability to be transmitted from person to person ».
Real false alarm?
The Russian state laboratory Vektor, at the origin of the discovery, has also announced « start developing a test system » and a vaccine. The virus is raging in several European countries, including France. But for the honorary professor of the National Veterinary School of Alfort specialist in medical pathologies of farmyard animals, Jeanne Brugère-Picoux, it is still too early to be alarmed.
“The important alert on the risk wrongly announced by the WHO of an influenza pandemic due to the panzootic H5N1 virus in 2005 should lead us to be somewhat cautious, she explains. This virus may have contaminated humans during very close contact with live poultry in Asia, but it has never adapted to humans. From 2003 to January 20, 2020, there were only 861 patients, including 455 deaths without human-to-human transmission, which does not meet the definition of an epidemic. “
In 2003, another variant of influenza A, H7N7, had mutated in the Netherlands to infect humans. “With this episode, we now know that it can give conjunctivitis, but that it is not necessarily fatal”, reports Jeanne Brugère-Picoux. Many questions remain unanswered, first and foremost that of possible clinical signs.
“Was there really an infection? “, also wonders Jean-Luc Guérin, professor at the National Veterinary School of Toulouse (ENVT) and researcher at INRAE, specializing in poultry farming and avian pathology. It is possible to find traces of the virus in employees, in constant contact with poultry dust, without the disease breaking out.
“Then, if there are indeed antibodies, therefore infection, it is still necessary to know if the virus has changed or if it is still the same virus”, continues the researcher. Cases of avian influenza transmission from birds to humans exist, but they remain rare. If this discovery does not seem to cause concern, the WHO assures in any case “Watch” possible future mutations of the virus.