[Influenza virus infections in Taiwan from 1979 to 1994]

In order to understand the epidemic trends of influenza virus infection in Taiwan, 5,677 throat-swab specimens were collected from June 1979 to December 1994. The influenza virus was detected in 300 specimens including samples collected at Taichung and Tainan from 1981 to 1982. Among them, 209 isolates (67.9%) were identified as influenza virus type A and 99 isolates (32.1%) were type B influenza virus. Influenza virus infection can be identified, based on the frequency of detection of the virus, throughout the year in Taiwan. Some strains were referred to as intermediate strains due to antigenic drift. About 80% of the isolates identified in this laboratory were from the children under 12 years old. The rate of isolation of the virus was about 47% during the epidemic season. The influenza virus strain A/Taiwan/1/86(H1N1) used as the standard strain for the CDC reagent kit was first isolated by this laboratory in April 1986. We isolated a new strain of influenza virus on December 16, 1991 and later the virus was identified as A/Beijing/32/92-like, which was first isolated on January 31, 1992 at Beijing. Prior to the identification of B/Panama/45/90, we isolated a strain similar to B/Panama/45/90 on January 3, 1990. Owing to delays in shipping of the isolated viruses to the CDC for further confirmation, however, the two new isolates missed the chance to be named as Taiwan strains and otherwise would be listed as standard Strains by the CDC.