Comparison of Serological Survey of Influenza Viruses on Pig Farm Workers by Hemagglutination Inhibition and Biochips

Pigs are believed to play a central role in the creation of pandemic viruses through reassortment because of their susceptibility to infection with both avian and human influenza viruses. Hemagglutinin is the major antigen of all types of influenza virus, and critical changes on its antigen shift are elucidated to be responsible for the attack on mankinds. To evaluate the exposure and prevalence rate caused by the work-related zoonic Influenza, a filed study, including questionnaire containing disease history, self syndromes, and personal hygiene status was conducted. Influenza H1N1 swine subtype and H3N2 human influenza viruses were used as the test strains. Exposure conditions were evaluated by serum titers by Hemagglutination Inhibition (HI) and Biochips. In total, two hundred workers, including 152 of exposed group, and 48 of non-exposed group were investigated. Statistical data from questionnaires shows over eighty percent clients had physical contact with swine excretes in exposed group, flu related syndromes were work related. From the results of blood samples, a positive rate about 27.5% (55) in hemagglutination-inhibition (HI) swine influenza specific antibody was found, and significaly higher in exposure group (p <0.01). The Protein extract containing Hemaglutinin (HA) of H3N2 influenza virus was printed on glass slides to fabricate a protein microarray and then probed with the sera from pigfarm workers to determine the reactivity of these protein with anti-HA IgG responses in the serum. From the statistic results of the relationships of specific antibody with the occupational exposure and personal hygiene habitats, and a tendency with pig flu disease were found. A significant higher rate of antibody test about 40% (8) was observed in those workers with severe flu syndromes than 26.1% (45) in those who were not (p <0.01). Significant correlations with symptoms were also observed from the results of HA protein biochips assay, but not so significant with the occupational exposure. We conclude that HA proteins can be used for examination for influenza infection on microarray system, that will be very convinient for the survey of HA typing in multiple strains examination simutaneously, to improve preventative and therapeutic measures. Key words: Influenza virus, pig-Farm Workers, zoonoses