Influenza surveillance in poultry market and its inter-species transmission in Taiwan
Journal
International Congress Series
Journal Volume
1219
Journal Issue
C
Pages
201-211
Date Issued
2001
Author(s)
Abstract
Background: Since Taiwan has high population density and a similar ecological environment to Mainland China, the epi-center of influenza viruses, it is very important to establish influenza virologic surveillance systems in both animal and human populations. The H5N1 Hong Kong Flu in 1997 and H9N2 in 1999 have showed that avian influenza viruses can cross the receptor of host species boundary and transmit to human. Therefore, the specific aim of this study is to understand the frequency of inter-species transmission in Taiwan. Methods: We have established an avian influenza virologic surveillance system in one of the largest live poultry markets in Taipei City from October 1999 to March 2000. Serum samples were collected from 341 blood donors, including veterinarians, poultry farm workers, and market employees. HI and microneutralization were used to detect specific antibody against H6, an endemic virus in chicken farms in southern Taiwan, and antibodies against H3, H4, and H9 viruses. Results: Among about 1300 fecal specimens of chickens and ducks collected, we isolated 12 H3 viruses, 14 H4 viruses, and 2 H6 viruses (i.e. 9 serotypes of HA and NA) from ducks. The isolation rates were 0% (0/580) and 7% (28/400) in chickens and ducks, respectively. Phylogenetic analysis of HA from 7 of our 12 H3 isolates showed the highest (93%) homology with A/equine/Jilin/89 (H3N8). Both phylogenetic relationship of HA and NP genes from selected representative strains (7 H3, 7 H4, and 2 H6) found they all fell into Eurasian lineage of avian influenza viruses. Their NP genes were away from the G1 lineage that was found in H5N1 strain isolated in Hong Kong in 1997. In addition, the results of HI and microneutralization tests found that they were all seronegative against two avian influenza virus strains [A/Duck/Czechoslovakia/56 (H4N6) and A/Shearwater/Australia/1/72 (H6N5)]. Conclusion: Continuous efforts by integrating animal, market and human influenza surveillance systems have provided the best early warning signals to detect new influenza virus activities for preventing potential pandemics and providing effective controls. © 2001 Elsevier Science B.V.
Type
journal article
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