title: Comparison of outbreaks of H5N1 highly pathogenic avian influenza in wild birds and poultry in Thailand.
abstract: Wild bird surveillance for highly pathogenic avian influenza (HPAI) H5N1 virus from 2004 to 2007 in Thailand indicated that the prevalence of infection with avian influenza H5N1 virus in wild birds was low (1.0%, 95% confidence interval [CI]: 0.7-1.2, 60/6,263 pooled samples). However, the annual prevalence varied considerably over this period, with a peak of 2.7% (95% CI: 1.4, 4.1) in 2004. Prevalence dropped to 0.5% (95% CI: 0.3, 0.8]) and 0.6% (95% CI: 0.3, 1.0) in 2005 and 2006, respectively, and then increased to 1.8% (95% CI: 1.0, 2.6) in 2007. During this period, 16 species from 12 families of wild birds tested positive for H5N1 virus infection. All samples from juvenile birds were negative for H5N1 virus, whereas 0.6% (95% CI: 0.4, 0.9) of pooled samples from adult birds were positive. Most positive samples originated from peridomestic resident species. Infected wild bird samples were only found in provinces where poultry outbreaks had occurred. Detection of H5N1 virus infection in wild birds was reported up to 3 yr after eradication of the poultry outbreaks in those provinces. As observed with outbreaks in poultry, the frequencies of H5N1 outbreaks in wild birds were significantly higher in winter. Further understanding of the mechanisms of persistence and ongoing HPAI H5N1 transmission between wild birds and domestic poultry is needed.
authors.affiliation: The Monitoring and Surveillance Center for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand. hjjar@yahoo.com
authors.forename: Jarunee
authors.initials: J
authors.lastname: Siengsanan
authors.forename: Kridsada
authors.initials: K
authors.lastname: Chaichoune
authors.forename: Rassameepen
authors.initials: R
authors.lastname: Phonaknguen
authors.forename: Ladawan
authors.initials: L
authors.lastname: Sariya
authors.forename: Phirom
authors.initials: P
authors.lastname: Prompiram
authors.forename: Waraporn
authors.initials: W
authors.lastname: Kocharin
authors.forename: Sririporn
authors.initials: S
authors.lastname: Tangsudjai
authors.forename: Sarin
authors.initials: S
authors.lastname: Suwanpukdee
authors.forename: Witthawat
authors.initials: W
authors.lastname: Wiriyarat
authors.forename: Rattapan
authors.initials: R
authors.lastname: Pattanarangsan
authors.forename: Ian
authors.initials: I
authors.lastname: Robertson
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Blacksell
authors.forename: Parntep
authors.initials: P
authors.lastname: Ratanakorn
mesh_terms: D000818:Animals; D000829:Animals, Domestic / Q000821:virology; D000835:Animals, Wild / Q000821:virology; D001717:Birds; D004196:Disease Outbreaks / Q000662:veterinary*; D004197:Disease Reservoirs / Q000662:veterinary / Q000821:virology; D005260:Female; D053124:Influenza A Virus, H5N1 Subtype; D005585:Influenza in Birds / Q000453:epidemiology* / Q000635:transmission; D008297:Male; D011200:Poultry; D015995:Prevalence; D012367:RNA, Viral / Q000032:analysis; D012621:Seasons; D018571:Sentinel Surveillance / Q000662:veterinary; D013785:Thailand / Q000453:epidemiology
chemical_list: D012367:RNA, Viral