J Wildl Dis.: Comparison of outbreaks of H5N1 highly pathogenic avian influenza in wild birds and poultry in Thailand.
Article Type: Report
Subject: Avian influenza (Risk factors)
Avian influenza (Diagnosis)
Avian influenza (Research)
Birds (Health aspects)
Birds (Research)
Disease transmission (Research)
Authors: Siengsanan, J.
Chaichoune, K.
Phonaknguen, R.
Pub Date: 12/01/2009
Publication: Name: Journal of Avian Medicine and Surgery Publisher: Association of Avian Veterinarians Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Association of Avian Veterinarians ISSN: 1082-6742
Issue: Date: Dec, 2009 Source Volume: 23 Source Issue: 4
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: Thailand Geographic Code: 9THAI Thailand
Accession Number: 252007017
Full Text: 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; 60/6263 pooled samples). However, the annual prevalence varied considerably over this period, with a peak of 2.7% (95% CI, 1.44.1) 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 H5NI 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 years 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.

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