Antibodies to type A influenza viruses in sera from nonhuman primates

The results of serological testing of nonhuman primate sera obtained over a four-year period showed a high incidence of antibodies to influenza virus strains of the H2 and H3 hemagglutinin sub-types. This would indicate that outbreaks of type A influenza virus infection occurred in certain primate species and suggest another possible reservoir for influenza virus in nature. Hemagglutination-inhibition (HI) testing of sera collected from African green monkeys captured in the Kenya-Tanzania area of East Africa demonstrated significant antibody titers to A/Hong Kong (HK)/68 (H3N2) virus in serum samples obtained 8 to 10 months prior to the first report of influenza-like illness in East Africa, and 3 to 5 months prior to the first report of outbreaks of acute respiratory disease in southeastern China due to A/HK/68 (H3N2). The results suggest that certain species of nonhuman primates may be involved in the epidemiology of influenza due to their close association with human living areas.