Jpn. J. Infect. Dis., 53, 2000

Laboratory and Epidemiology Communications
Influenza C Viruses Isolated durlng the 1 999‑2000 Influenza Season
in Saitama Prefecture, Japan
Shinichi Shimada*, Kuniaki Suzukil , Katsumi Arai2, Michiyo Shinohara,
Kazue Uchida, Yukari Segawa and Yoji Hoshino
Deparlment of Infectious Diseases, Saitama Institute of Public Health,Kami‑Ohkubo 639‑I, Urawa 338‑0824,
lsuzuki Childylen i Clinic,

Nakamachi I‑6‑4, Urawa 336‑0007 and2Department of Pediatrics, Chichibu CiO, IIospital,
Sakuragi‑cho 819, Chichibu 368‑0025, Saitama

Communicated by Kunihiko Masukawa(Accepted August 1 5, 2000)

and HAtiters rose up to 1 :32 or 1:64. They were negative in
an innuenza Avirus detection EIA assay, Directlgen FluA

Aninnuenza outbreakthat occurred丘om November 1 999 toMarch 2000 in Saitama Prefecture was caused by A(Hl ) andA(H3) viruses a! were outbreaks throughout Japan･ During
this season, We lSOlated 293 influenza A viruses from 553(Becton Dickinson Co., Sparks, Md., USA), but positive in
RTIPCR specific for the influenza C virus NS gepe (5)･
Hemagglutination inhibition test uslng rabbit antlSerum
against C/Ann Arbor/ 1 /50 (this test was kindly performed byDrs. H. Nishimura andA. Ohmi, Virus Research Center, Sendai

nasopharyngeal swab specimens mostly collected by pediatri‑cians at private clinics or hospitals; 185 were A(Hl) and 108†ere A(H3) viruses･ In addition, we obtained two innuen.za C

National Hospital, Miyagi) Confirmed that the isolates werevlruS isolates from throat swabs in separate climical settlngS.

innuenza C viruses.

Innuenza Cviruses had been isolated sporadical)y through‑out the year (1), including during the influenza season (2),Causative agents of acute resplratOry infections cannot bebut far lessfrequently than influenza A and B viruses. However,diagnosed clinically. Laboratory diagnosis should be conducted

an ou他reak at a nursery (3) and regional epidemics lasting

carefully so as to differentiate influenza viruses A, B and C,

for as long as 3 months (4) were reported in Japan･

parainnuenza viruees･ respiratory syncytial virus (RSV) andThe first innuenza Cvirus isolate (obtained on 24 January

other respiratory viruses.

2000) was from a 1 ‑year‑old male with influenza‑likesymptoms. He had a fever of38.5oC, a cough,runny nose,REFERENCES

and malaise. A throat swab specimen was collected and placed

1. Moriuchi, H., Katsushima, N., Nishimura, H., Nakamura
K. and Numazaki, Y. (1991): Community‑acquiredin 2 ml of Veal Infusion Broth (Difco Laboratories, Detroit,Mich., USA) Containing 0.5% bovine semm albumin, 500 U/ml ofpenicillin, I mg/ml of streptomycin, 0.06 mg/ml orinfluenza C virus infection in children. J. Pediatr., 1 1 8,gentamicin and 0.02 mg/ml of amphoterisin B. He received
two shots of influenza A and B virus vaccine in Novemberand December of 1999. He recovered in 2 days. No other235‑238.

2. Greenbaum, E., Morag, A. and Zakay‑Rones, Z. (1998):

members of his family had signs ofresplratOry infection wheninnuenzaAand B viruses. J. Clin. Microbio1., 36, 1441‑

Isolation of innuenza C virus during an outbreak of1442.

he got ill.

3. Katagiri, S., Ohizumi, A. and Homma, M. (1983): An

TYle Second isolate (obtained on 29 February 2000) was fromoutbreak of type Cinfluenzaina children's home. J. InfTect.

a 4‑yeaト01d female with a fever (37 I 40oC for 5 ‑ 6 days), aDis., 148, 51‑56.
4. Matsuzaki, Y, Nakamura, K., Mizuta, K., Katsushima,N., Sakamoto, M. and Suzuki, H. (2000): Influenza C

cough andrunny nose. She had no previous influenza vaccina‑tion. Her brother and some of her kindergarten mates hadsimilar symptoms during this period, but clinical specimens
fわr isolation orthe vims were not obtained.

outbreaks which occured in Yamagata prefecture in 1 996

Cells such as MDCK, CaC0‑2, LLC‑MK2 and HeLa were
inoculated with the specimens. Only the MDCK cells
developed weak cytopathogenic effects (CPEs) at 5 to 6and 1998. Clin. Viro1., 28, 41‑46 (in Japanese).

5. Claas, E. C. J., Sprenger, M. J. W., Kleter, G. E. M., Van
Beek, R., Quint, W. G. V. and Masurel, N. (1992): Type‑days. The supernatants of the culture agglutinated chicken

Specific identification of innuenza viruses A, B and C

erythrocytes but not gulnea plg erythrocytes. A触r passagesby polymerase chain reaction. ∫. Virol. Methods, 39,トin MDCK cells, the culture supematants gave clearer CPEs,

13.

*Co汀eSpOnding author: Fax: +8ト48‑840‑1041 , E‑mail: vims3 1@f3.dion.ne.jp170