tetano
Editor, Senior Moderator
Seroprevalence to avian influenza A(H7N9) virus among poultry workers and the general population in southern China: a longitudinal study
Xin Wang*,1,
Shisong Fang*,1,
Xing Lu*,1,
Cuiling Xu2,
Benjamin J. Cowling2,
Xiujuan Tang1,
Bo Peng1,
Weihua Wu1,
Jianfan He1,
Yijun Tang1,
Xu Xie1,
Shujiang Mei1,
Dongfeng Kong1,
Renli Zhang1,
Hanwu Ma1, and
Jinquan Cheng1
+ Author Affiliations
1Major Infectious Disease Control Key Laboratory, Key reference laboratory of pathogen and biosafety, Shenzhen Center for Disease Control and Prevention, Shenzhen, People's Republic of China
2Division of Epidemiology and Biostatistics, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
Correspondence to: Dr. Jinquan Cheng or Dr. Renli Zhang, Major Infectious Disease Control Key Laboratory, Key reference laboratory of pathogen and biosafety, Shenzhen Center for Disease Control and Prevention, Shenzhen, People's Republic of China, cjinquan@vip.sohu.com
↵* These authors contributed equally to this work
Abstract
Background. Confirmed human cases of avian influenza A(H7N9) virus infection continue to occur in mainland China. Few confirmed cases have occurred in poultry workers despite potentially higher rates of exposure.
Methods. A serological survey was conducted in May and December 2013 in poultry market workers, and in March and September 2013 in the general population. Blood samples were collected and tested for antibodies to H7N9 and H5N1 viruses by hemagglutination-inhibition assays. Multivariable analysis was employed to identify risk factors related to H7N9 infection indicated by serology among poultry workers.
Results. In the poultry workers, 36/501 (7.2%) in May and 56/375 (14.9%) in December had HI antibody titer ≥1:160 to H7N9. Of 96 individuals who participated in both surveys, 52 (54.2%) workers had ≥4-fold rise in H7N9 antibody titers from May to December. In a multivariable analysis, female sex (odds ratio 2.713; 95% CI: 1.098-6.705) and ≥10y of occupational exposure (odds ratio, 3.592; 95% CI: 1.246-10.354) were identified as risk factors for infection. Seroprevalence against H5N1 at ≥1:160 was low in May (4/501; 0.8%) and December (3/375; 0.8%). In the general population, 0/417 individuals in March and 0/408 individuals in September had antibody titer ≥1:160 to H7N9 or to H5N1.
Conclusions. While none of the participants in our study had virologically confirmed H7N9 infection, the high proportion of poultry workers with serologic evidence of H7N9 infection between May and December 2013 suggests a substantial risk of mild H7N9 infections in this group, supporting stricter control measures in live poultry markets.
Received March 12, 2014.
Accepted May 19, 2014.
http://cid.oxfordjournals.org/content/early/2014/05/27/cid.ciu399.abstract
Xin Wang*,1,
Shisong Fang*,1,
Xing Lu*,1,
Cuiling Xu2,
Benjamin J. Cowling2,
Xiujuan Tang1,
Bo Peng1,
Weihua Wu1,
Jianfan He1,
Yijun Tang1,
Xu Xie1,
Shujiang Mei1,
Dongfeng Kong1,
Renli Zhang1,
Hanwu Ma1, and
Jinquan Cheng1
+ Author Affiliations
1Major Infectious Disease Control Key Laboratory, Key reference laboratory of pathogen and biosafety, Shenzhen Center for Disease Control and Prevention, Shenzhen, People's Republic of China
2Division of Epidemiology and Biostatistics, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
Correspondence to: Dr. Jinquan Cheng or Dr. Renli Zhang, Major Infectious Disease Control Key Laboratory, Key reference laboratory of pathogen and biosafety, Shenzhen Center for Disease Control and Prevention, Shenzhen, People's Republic of China, cjinquan@vip.sohu.com
↵* These authors contributed equally to this work
Abstract
Background. Confirmed human cases of avian influenza A(H7N9) virus infection continue to occur in mainland China. Few confirmed cases have occurred in poultry workers despite potentially higher rates of exposure.
Methods. A serological survey was conducted in May and December 2013 in poultry market workers, and in March and September 2013 in the general population. Blood samples were collected and tested for antibodies to H7N9 and H5N1 viruses by hemagglutination-inhibition assays. Multivariable analysis was employed to identify risk factors related to H7N9 infection indicated by serology among poultry workers.
Results. In the poultry workers, 36/501 (7.2%) in May and 56/375 (14.9%) in December had HI antibody titer ≥1:160 to H7N9. Of 96 individuals who participated in both surveys, 52 (54.2%) workers had ≥4-fold rise in H7N9 antibody titers from May to December. In a multivariable analysis, female sex (odds ratio 2.713; 95% CI: 1.098-6.705) and ≥10y of occupational exposure (odds ratio, 3.592; 95% CI: 1.246-10.354) were identified as risk factors for infection. Seroprevalence against H5N1 at ≥1:160 was low in May (4/501; 0.8%) and December (3/375; 0.8%). In the general population, 0/417 individuals in March and 0/408 individuals in September had antibody titer ≥1:160 to H7N9 or to H5N1.
Conclusions. While none of the participants in our study had virologically confirmed H7N9 infection, the high proportion of poultry workers with serologic evidence of H7N9 infection between May and December 2013 suggests a substantial risk of mild H7N9 infections in this group, supporting stricter control measures in live poultry markets.
Received March 12, 2014.
Accepted May 19, 2014.
http://cid.oxfordjournals.org/content/early/2014/05/27/cid.ciu399.abstract