Mortality rates adjusted for unobserved deaths and associations with Newcastle disease virus serology among unvaccinated village chickens in Myanmar

Henning, Joerg, Morton, John M., Hla, T. and Meers, Joanne (2008) Mortality rates adjusted for unobserved deaths and associations with Newcastle disease virus serology among unvaccinated village chickens in Myanmar. Preventive Veterinary Medicine, 85 3-4: 241-252. doi:10.1016/j.prevetmed.2008.01.014


Author Henning, Joerg
Morton, John M.
Hla, T.
Meers, Joanne
Title Mortality rates adjusted for unobserved deaths and associations with Newcastle disease virus serology among unvaccinated village chickens in Myanmar
Journal name Preventive Veterinary Medicine   Check publisher's open access policy
ISSN 0167-5877
Publication date 2008-01-01
Year available 2008
Sub-type Article (original research)
DOI 10.1016/j.prevetmed.2008.01.014
Open Access Status
Volume 85
Issue 3-4
Start page 241
End page 252
Total pages 12
Editor Salman, M.D.
Place of publication Netherlands
Publisher Elsevier BV
Language eng
Subject C1
070706 Veterinary Medicine
970107 Expanding Knowledge in the Agricultural and Veterinary Sciences
Abstract Village chickens are an important livestock for many rural families in Myanmar and other developing countries. Village chickens are kept under free-ranging conditions, with confinement only at night. Therefore, it is likely that some deaths are not observed by farmers. We conducted a longitudinal study from November 2003 until May 2004 to describe temporal patterns of mortality of village chickens in 10 villages in Myanmar. Field veterinarians first identified the numbers of birds in all chicken-owning households in each village. We then selected 307 households randomly with stratification by flock size. Each study household was then visited once monthly at which time questionnaires were completed recording current flock structure and numbers of hatchings, mortalities, sales and birds consumed since the previous visit. In addition, sera were collected from a sample of adult birds and growers. Depending on month and age group of chicken, from 71 to 231 (out of 290–307) households had discrepancies in the counts of birds. For chicks, at least one-quarter of the households had unobserved losses of at least 5 chicks per household (maximum 66 chicks); unobserved losses were less for growers and adult chickens. The median month-specific, village-specific mortality rates per 1000 bird-days at risk (counting missing birds as deaths) ranged from 0.8 to 1.7 for adults, from 0.4 to 4.7 for growers and from 8.0 to 16.5 for chicks. Across all birds, the prevalence of protective titres against Newcastle disease virus was 79% (95% confidence interval 74, 84); higher prevalences of protective titres were associated with reduced mortality rates in the following months.
Keyword Mortality rates
Village chickens
Scavenging
Unobserved mortality
Myanmar
Newcastle disease
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Veterinary Science Publications
 
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Created: Mon, 23 Mar 2009, 20:15:07 EST by Narelle Poole on behalf of School of Veterinary Science