The summer assessment of the European Food Safety Authority reports an “unusual persistence of the virus in wild birds”. Faced with a degradation of the health situation, France has noted its level of risk.
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This is “the most important avian -to -influense epidemic observed to date in Europe”. In a balance sheet published Monday, October 3, the European Food Safety Authority (EFSA) confirms that the 2021-2022 season has been extraordinary in several respects. Over the period from June to September, EFSA reports an “unprecedented number of detections from the highly pathogenic avian influenza virus in wild and domestic birds”. Summer was notably marked by an “unusual persistence of the virus in wild birds” observed in fifteen European countries. Mortal foci have been noted among colonies of breeding sea birds (seagulls, gulls, crazy bassan …) on European coastlines, especially in France, the Netherlands and the United Kingdom.
However, the summer period is normally that of the lull for the circulation of the avian influenza virus, which traditionally diffuses during the phases of wild bird migration from north to south. Consequence of this jostled seasonality and the persistence of the virus among sedentary fauna: farms were not spared during the summer, when they have already experienced a particularly virulent epidemic in the first half of 2022. In total, 47 Millions of poultry had to be shot dead in Europe this year, including 16 million in France. After a black winter and spring, the period June-September saw “the number of epidemic foci in domestic birds decrease compared to previous months, but it was more than five times higher compared to the same period the previous year “, Continues EFSA.
Transmissions to monitored mammals
Another notable fact, according to the European agency: “The geographic scope of this year’s epidemic is unprecedented, with reported cases ranging from the Svalbard Islands, Norway, south of Portugal and also far away is that Ukraine, affecting a total of thirty-seven countries of the European continent. “This same H5N1 virus also crossed the Atlantic in the fall of 2021 and led to an unprecedented level of contamination in North America. In France, areas hitherto relatively spared are found this year on the front line, notably Brittany, with a risk of diffusion between high farms, due to their high density.
Finally, the epidemic has the particularity this year to be dominated by a subgroup of H5N1 virus, clade 2.3.4.4b, identified for the first time in the Netherlands in October 2020. These viruses being very Conceived to reassorts, several genotypes have been circulating, some of which have been very recently that has been very recently since June. The adaptability of these viruses are thus one of the avenues for explaining their persistence during the summer. The health authorities are particularly monitoring transmissions to mammals, the virus having been detected this year in many species (foxes, badgers, polers, lynx, porpoises, otters, seals, dolphins, brown bear …). No broadcasting between mammals was however noted. As for the risk of transmission to humans, it is deemed weak in the general population by EFSA, and low to means for those involved professionally in farms.
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