Human cases of influenza A/H5N8 virus infection

On February 19, 2021 the WHO H5 Reference Laboratory of the State Research Centre for Virology and Biotechnology VECTOR (FSRI SRC VB VECTOR) Rospotrebnadzor of the Russian Federation notified the WHO about cases of human infection with avian influenza A(H5N8) virus. These are the first laboratory confirmed human cases of A(H5N8) virus infection to be reported worldwide. The genome sequences of the viruses from a human case and from poultry are shared in GISAID (EPI_ISL_1038924).

On December 21, 2020, FBRI SRC VB VECTOR Rospotrebnadzor received 56 serum samples and 37 nasopharyngeal swabs samples from farm workers of Vladimirskaya Poultry Farm in Astrakhan (Russian Federation) who were potentially exposed during a large-scale outbreak of highly pathogenic avian influenza A(H5N8) in poultry. Influenza A virus RNA was detected by RT-PCR in 7 swabs, and 5 of these were confirmed to have subtype H5. A virus was isolated from 1 human swab and next-generation sequencing confirmed this virus to be of subtype A(H5N8) with an HA of clade 2.3.4.4b. The individuals had no specific clinical signs of acute respiratory disease. Seroconversion was detected by microneutralization assay, hemagglutination inhibition assay with horse red blood cells, and binding of the virus to serum antibodies as measured by Bio-layer interferometry. Further investigations are ongoing.

D110N – or D94N (H5N1 2005) was reported to be a host specificity mutation. S159F – or S145F (H5N1 2004) was reported to be an antigenic escape mutant (J Virology, 2007 DOI: 10.1128/JVI.01522-07)