A new influenza virus A/H3N2 variant of Taiwan origin.

A clinical isolate of influenza virus A/H3N2 from a one-year-old boy with pharyngitis was examined by using RNA-polymerase chain reaction (PCR) for amplification of viral cDNA and subsequent DNA sequencing with asymmetric PCR. Since antigenic drift has been found in recent A/H3N2 isolates, this strain was compared with A/Shanghai/24/90 and other A/H3N2 strains, collected at the Centers for Disease Control and Prevention (CDC) in Atlanta, GA, USA. It was found that the steady changes of amino acid at location 190 and 262 of HA1 region were very similar to some recent isolates. This 1989 isolate may be the origin of a new influenza virus A/H3N2 variant.