Evaluation on the risks of H5, H7 and H9 avian influenza infections in Guangzhou: using data from the 2006-2012 avian influenza surveillance program / 中华流行病学杂志

<p><b>OBJECTIVE</b>To analyze the results of avian influenza surveillance program in Guangzhou from 2006 to 2012 and to evaluate the risk of infections with H5, H7 and H9 subtypes avian influenza viruses.</p><p><b>METHODS</b>Avian influenza surveillance system in Guangzhou consisted five components:serum surveillance on occupational population, environmental specimen surveillance of avian influenza virus, avian flu emergency surveillance, influenza viruses surveillance on ILI patient and surveillance on pneumonia of unknown causes. Hemagglutination inhibition test was conducted to detect the antibodies against H5, H7 and H9 while RT-PCR was used to test the nucleic acid of H5, H7 and H9 viruses.</p><p><b>RESULTS</b>From 2006 to 2012, 4103 serum specimens were collected from occupational populations and the overall positive rate of H5/H7/H9 antibodies was 3.82% . The antibody positive rates for H5, H7 and H9 were 0.22% ,0.00% and 3.70% respectively. 4 serum specimens for H5 and H9 simultaneously showed antibody positive. The positive rate of H9 among occupational populations(4.21%)appeared higher than that from the control population(2.16%). 2028 specimens were collected from poultry sites and 55 samples found positive for H5 nucleic acid (positive rate:2.71%), 14 samples positive for H9 nucleic acid (positive rate:0.69%), 5 specimens, simultaneously positive for H5 and H9 nucleic acids. However, none of the samples showing H7 nucleic acid positive. From 2006 to 2012, all the tested H5/H7/H9 virus were negative from the respiratory/serum specimens among those close contacts of patients or high risk groups through the avian flu emergency surveillance program,ILI patient influenza virus surveillance programs or pneumonia of unknown causes surveillance program.</p><p><b>CONCLUSION</b>Contamination of H5/H9 avian influenza virus did exist in the poultry sites in Guangzhou, especially in the wet Markets. The H5/H9 avian influenza virus caused asymptomatic infection was proved to be existed within the population exposed to the poultry, suggesting that the poultry occupational population in Guangzhou was under the risk of avian influenza virus infection.</p>

Avian influenza virus infection in people occupied in poultry fields in Guangzhou city / 中华流行病学杂志

Objective To conduct serological investigation on H5N1/H9N2/H7N7 infection among people occupied in poultry fields. Methods Serum samples were collected from people working in live poultry and none-poultry retailing food markets, poultry wholesaling, large-scale poultry breading factories and in small-scale farms, wide birds breeding, swine slaughtering houses and from normal population. Antibodies of H5, H9 and H7 with hemagglutination inhibition and neutralization tests were tested and analyzed. Logistic regression and χ2 test were used. Results Among 2881 samples, 4 were positive to H5-Ab(0.14%), 146 were positive to H9-Ab (5.07%) and the prevalence of H9 among people from live poultry retailing (14.96%) was the highest. Prevalence rates of H9 were as follows: 8.90% in people working in the large-scale poultry breading factories, 6.69% in the live poultry wholesaling business, 3.75% in the wide birds breeding, 2.40% in the swine slaughtering, 2.21% in the non-poultry retailing, 1.77% in the rural poultry farmers and 2.30% in normal population. None was positive to H7-Ab among 1926 poultry workers. Conclusion The H5 prevalence among people was much lower than expected, but the H9 prevalence was higher. None of the populations tested was found positive to H7-Ab. There was a higher risk of AIV infection in live poultry retailing, wholesaling and large-scale breading businesses, with the risk of live poultry retailing the highest. The longer the service length was, the higher the risk existed.

Analysis on the risk factors of severe acute respiratory syndromes coronavirus infection in workers from animal markets / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the possible risk factors of severe acute respiratory syndromes coronavirus (SARS-CoV) infection in workers from animal markets.</p><p><b>METHODS</b>Self-designed questionnaires were used and serum samples were tested. Logistic regression analysis was used to analyze the data.</p><p><b>RESULTS</b>Results from simple factor logistic regression analysis showed that jobs which dealing with domestic livestock, wild livestock, wild animals, aquatics were related to risk factors of SARS-CoV infection. Results from multifactor logistic regression analysis showed that jobs that dealing with wild livestock and poultry were important risk factors with OR 12.28 and 0.41.</p><p><b>CONCLUSION</b>Job that dealing with palm civets was the main risk factor of SARS-CoV infection in animal market workers.</p>

An epidemiologic investigation on infection with severe acute respiratory syndrome coronavirus in wild animals traders in Guangzhou / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate status of infection with severe acute respiratory syndrome coronovirus (SARS-CoV) in traders of wild animals wholesale markets in Guangzhou.</p><p><b>METHODS</b>Serum antibody against SARS-CoV IgG was determined cross-sectionally and symptoms of respiratory infection were investigated retrospectively for part of traders of three wholesale markets for wild animals in Guangzhou.</p><p><b>RESULTS</b>Overall rate of infection with SARS-CoV in 635 traders was 16.69%, varying in three different markets. Infection rate in market A mainly engaging in wild animals ranked the highest of 25.61%, significantly higher than that in markets B and C engaging in domestic fowls and snakes. Infection rate in traders only engaging in civet cats was 58.54%, significantly higher than that in traders engaging in snakes only (9.46%). In market A, infection rate varied in different persons, 59.34%, 20.59%, 16.00%, 15.22%, 10.40% and 9.68% in traders engaging in wild animals, managers, children of the traders, traders engaging in domestic fowls, traders engaging in snakes, and traders engaging in frozen food, respectively, in a decreasing pattern as their contact opportunities. During the period of SARS epidemic, detection rate of SARS-CoV antibody in people with symptoms of acute respiratory infection was higher (30.70%) than that in those without such symptoms (20.08%). Prevalence of symptoms of acute upper respiratory infection in people with positive antibody against SARS-CoV was higher (49.28%) than that in those with negative antibody (30.35%).</p><p><b>CONCLUSIONS</b>Infection with SARS-CoV in traders of animal markets possibly related to their direct exposure to wild animals, particularly to civet cats. During the period of SARS epidemic, some of the traders did infect with SARS-CoV, but they were neglected due to clinically inapparent manifestations.</p>