An outbreak of influenza caused by variant strains of new influenza A[H1N1
Fan, Z.H.; Mu, S.H.; Yang, B.; Zhao, H.W.; Lao, W.N.; Jing, Y.L.; Hu, X.M.; Hu, M.R.
Hua Xi Yi Ke da Xue Xue Bao 18(4): 385-388
1987
ISSN/ISBN: 0257-7712 PMID: 3449432 Document Number: 294394
In the present paper, the results of investigation of influenza outbreak arisen from variant strains of new influenza A[H1N1] in a university at Chengdu in April 1986 are presented. The number of cases was 827 (attack rate was 15 percent), in which attack rate in students was 28 percent. Thirty two gargle specimens from acute period influenza cases were collected. Three strains viruses were isolated from these specimens. Surface antigens of these three strains viruses were identified by hemagglutination inhibition test (HI) using standard immune serum of influenza of different subtypes. The results in HI showed that antigenicity of three isolates were similar to A/Qingdao/85-42 [H1N1] which was variants of new influenza A [H1N1]. In addition, twenty one pair serum specimens collected from acute period and convalescence cases were examined by HI using these three new strain viruses isolated as well as A/Qingdao/85-42 [H1N1]. The results showed that titre of HI antibodies rise twice to eightfold in 61.8 percent convalescence serum specimens. Our results suggest that the variants of new influenza A [H1N2] might be transmitted from the north to the south in our country.