Isolation of influenza virus type B, January-February - Sendai City, Osaka City
(IASR 2000; 21: 75-76)

Sendai City:

On February 14, 2000, influenza type B virus was isolated from a specimen forwarded by a sentinel surveillance facility in Sendai City. The specimen was collected from an 11 years old girl, who developed illness on January 29, and she visited outpatient clinic on January 31. Main symptoms included fever to 37.7C, symptoms to the upper respiratory tracts.

Gargling fluid was collected on that day, and MDCK cell yielded virus on February 3. Hemagglutination inhibition (HI) test provided by NIID for this season revealed that antibody increased 1:160 against B/Yamanashi/166/98. The National Sendai Hospital reported that influenza B virus was isolated from her classmate girl around the same time. As of March 15, influenza B is not isolated from both laboratories.

Reported by Kyoko Aihara, Masanori Kumagai, Yasuhiko Hayakawa, and Ken Sasaki, Sendai City Institute of Public Health; Michiko Okamoto and Syu-ichi Nishimura, Virus Research Center, the National Sendai Hospital; Tomoyuki Ikeda, Ikeda Clinic; Yukio Nagai, Nagai Pediatric Clinic

Osaka City:

During December 4, 1999 to March 13, 2000, 184 strains of influenza virus were isolated in Osaka city. Among them, only one strain was identified as influenza virus type B.

The virus was isolated from a 19 months old girl living in Osaka city. She developed illness on February 21 with fever to 40C, symptoms to the upper respiratory tract, and anorexia. Rapid influenza A diagnostic kit resulted negative.

Gargling fluid collected on February 24 was inoculated on MDCK cell, and obvious CPE was observed. Virus hemagglutinination (HA) titer against guinea pig red blood cell was 1:32.

Hemagglutination inhibition (HI) test using antisera provided by NIID revealed that the virus belongs to B/Yamagata-like strains (Table).

Reported by Tsukasa Murakami, Hideyuki Kubo, and Kosuke Haruki, Osaka City Institute of Public Health and Environmental Sciences; Sachiko Onoe, Osaka Police Hospital

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