Retrospective survey of avian influenza H5N1 infection in Northern Vietnam by using a combinational serologic assay

摘要

Outbreaks of highly pathogenic avian influenza H5N1 virus have occurred in Vietnam since 2003. However, how people got avian H5N1 infection in Northern Vietnam is still unclear. We therefore performed a combination of the serologic assays H5N1 ELISA and H5 western blot to detect anti-H5N1 specific antibodies. Sera samples of 149 subjects with suspected H5N1 infection from three provinces of Northern Vietnam were collected from September 2006 to March 2007. Our results indicated that this combinational assay showed high sensitivity (100%) and specificity (95%) when compared with hemagglutinin inhibition (HI) assay. Fifty-one sera samples (34.2%) contained specific antibodies against H5N1 viruses. Poultry raisers (32/77;41.6%) showed higher H5N1 infection rates than slaughterers (12/41;29.3%) and health care workers (7/31;22.6%). Contact history with sick or dead poultry in household or slaughter-house (p < 0.05) and lack of protective equipment use when in contact with dead poultry (p < 0.05) were risk factors found to be associated with H5N1 infection. In this study, we established an alternative serologic assay for H5N1 diagnosis, and we hereby present seroepidemiologic data of H5N1 infection in Northern Vietnam.