The first isolation of influenza virus type B in 1999/2000 season, December 1999 - Fukuoka City & Hiroshima
Vol. 21 No. 2 p. 6 (Page number indicates that of Japanese-version prints.)

Fukuoka City

Influenza B virus was isolated from a 10 years old boy with acute upper respiratory inflammation through a surveillance sentinel clinic in Higashi ward, Fukuoka city. He presented fever (max.39.4C), coughing, tracheal inflammation, and joint pain. There is no other patients in his family. Specimen (gargling water) from the patient was inoculated on MDCK cell. Isolated virus was examined for hemagglutination inhibition test using antisera provided by the influenza center, NIID, and it was identified as influenza B virus.

Reported by Virology Section, Microbiology Division, Fukuoka City Institute for Hygiene and Environment.

Hiroshima Pref.

According to the recent influenza epidemics report, only one case of influenza B virus isolation is reported on December 13, 1999, from a 10 years old boy in Fukuoka. In Hiroshima Prefecture, an influenza B strain was isolated on December 8, 1999, from one year old boy living in Takamiya town, Takada county. He developed fever to 38C, upper respiratory inflammation, vomiting, and diarrhea. Detection of influenza virus gene by RT-PCR method and virus isolation using MDCK cell were attempted. Gene fragment was amplified when NS gene specific influenza B primar pair was applied. MDCK cell yielded virus, which agglutinates with guinea pig and chicken red blood cell. Hemagglutination inhibition (HI) test was conducted using the antisera kit for 1999/2000 season provided by the Laboratory of Respiratory Viruses, NIID. Titer was increased to <1:10 against influenza A/H1, influenza A/H3, and influenza B. HI test was conduced using the antisera kit for 1997/1998 and 1998/1999. Titer was increased to 1:10 against B/Mie/1/93, and 1:40 against B/Harbin/07/94 respectively (Table).

The epidemic strains are B/Yamagata/18/88 and B/Victoria/2/87 these years in Japan (IASR, Vol.20, No.12, 1999). The isolated strain is derived from B/Harbin/07/94, however, it is supposed to be antigenically different from B/Yamanashi/166/98.

No other influenza B strains are not isolated in Hiroshima Prefecture, including the same area at the same time period.

Reported by Shin-ichi Takao, Yukie Shimazu, Shinji Fukuda, Masahiro Noda, Shizuyo Tokumoto, Hiroshima Prefectural Health and Environmental Center; Atsushi Fujita, and Toru Komazawa, Koseiren Yoshida General Hospital.

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