During 2020, high pathogenicity avian influenza (HPAI) A(H5N1) clade 2.3.4.4b viruses arose from previously circulating influenza A(H5Nx) viruses and spread predominantly via migratory birds to many parts of Africa, Asia and Europe. This epizootic event has led to unprecedented numbers of deaths in wild birds and caused outbreaks in poultry. In late 2021, these viruses crossed the Atlantic Ocean to North America and subsequently reached South America in October 2022. Over the past few years, there have been increased detections of A(H5N1) viruses in non-avian species globally including wild and domestic (companion and farmed) terrestrial and marine mammals, with recent cases in livestock in the United States of America. The majority of A(H5N1) viruses characterized genetically since 2020 belong to the haemagglutinin (HA) H5 clade 2.3.4.4b, with some regional exceptions. Since the beginning of 2021, 35 detections of A(H5N1) virus in humans have been reported to WHO, along with five cases of A(H5) virus detection in persons exposed to A(H5N1) infected animals. Of these human cases where the A(H5) clade is known (n = 31), 17 have been caused by clade 2.3.4.4b viruses.
URI : https://www.africavet.com/wp-content/uploads/2024/08/cd1970en.pdf
Année de publication : 2024
Lieu de publication: Rome, Italy ; Geneva, Switzerland ; Paris, France ;
Pages : 12 p.
Auteur(s) : FAO; WHO; WOAH;
Éditeur(s) : FAO ; WHO ; World Organisation for Animal Health (WOAH) ;
Type de produit : Policy brief
