Cases of H7N9 avian influenza, a major strain in humans, have been confirmed on a chicken farm in the United States, already affected by H5N1, according to the World Organization for Animal Health (WHO). The H7N9 virus was detected on a farm in Noxubee County, Mississippi. This strain, absent since 2017, was identified alongside H5N9, recently discovered in January. More than 47,600 chickens have been culled, and epidemiological investigations and increased surveillance are being conducted by U.S. authorities.
The H5N1 and H7N9 strains, which appeared in 1997 and 2013 respectively, are associated with human cases of avian influenza. H7N9, which causes severe respiratory illness, infected 1,668 people and caused 616 deaths between 2013 and 2021, according to the FAO. Currently, H5N1 is circulating heavily in animals, with rare transmissions to humans, but this fuels fears of a pandemic.
The lack of transparency from US authorities, exacerbated under the Trump administration, adds to these concerns. In early January, the first human death linked to H5N1 was reported in the United States, with all human cases attributed to direct exposure to animals, with no human-to-human transmission.
Pascal Lemontel
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