Fatal infection of a novel canine/human reassortant H3N2 influenza A virus in the zoo-housed golden monkeys

In June 2022, seven golden monkeys (Rhinopithecus roxellana) developed flu-like symptoms in succession at a zoo in Jiangsu Province, China, and two died of respiratory distress. Histopathological and immunostaining results supported a diagnosis of pulmonary infection with influenza virus.

An H3N2 canine/human reassortment virus, designated A/golden monkey/Jiangsu/1/2022 (Gm-1), was isolated from the lungs of deceased animals. Sequencing analysis revealed that except for PB1 gene that was 99% similar to that from human H1N1 virus (A/WSN/1933, WSN), the other 7 segments of Gm-1 were entirely derived from previously circulating canine H3N2 virus (A/canine/Jiangsu/06/2010, JS06). To determine whether the human-origin PB1 segment conferred a virulence advantage to Gm-1, we reconstructed this reassortant event using reverse genetics and generated two reassortment viruses, rGm-1 and rJS06.