Characterization of the haemagglutinin and neuraminidase antigens of some recent avian type A influenzavirus isolates from Hong Kong

Abstract

During 1969 type A influenzaviruses were isolated from three outbreaks of disease among domestic ducks in Hong Kong. The isolates were characterized in haemagglutination inhibition and neuraminidase inhibition tests with antisera to prototype avian and human influenza strains. A/duck/Hong Kong/46/69 and 120/69 contained haemagglutinin and neuraminidase antigens related to those of A/turkey/Wisconsin/66. The neuraminidases of these Hong Kong isolates, like that of turkey/Wisconsin/66, were antigenically closely related to those of human Asian influenzaviruses. A/duck/Hong Kong/826/69 contained haemagglutinin and neuraminidase antigens related to those of chicken/Scotland/59 and tern/South Africa/61, respectively. The duck influenza A isolates represent the first viruses of their antigenic variety to be isolated in South-East Asia. The possible epidemiological significance of the duck/Hong Kong/69 strains is discussed.