CDC: Human Infection with HPAI A(H5N1) virus in Chile
On 17 April 2023, the US CDC provided information on the genomic analysis of the samples from the first human infected with avian influenza A(H5N1) in Chile. Identified close contacts tested negative, so no further spread of the virus was observed. No human-to-human transmission is detected to date. The risk assessmentremains the same - low risk for infection in humans. The detected virus was identified as having a clade 2.3.4.4b and was determined to be the same genotype as circulating in wild birds in South America. No reassortment of the viral genes was identified. Two markers for mammal adaptation have been detected in the PB2 gene (PB2 D701N and Q591K) which have been described to improve the replication and impact pathogenesis in mammals and are assumed to have been acquired after infection within the human host. The exact source and way of transmission to this case is under investigation.
