A retrospective study of factors associated with Newcastle disease outbreaks in village indigenous chickens.

摘要

Although the epidemiology of Newcastle disease in commercial poultry systems is well documented, its ecology in indigenous birds, especially in tropics, is not adequately reported. The objective of this study, therefore, was to determine the risk factors associated with occurrence of Newcastle disease in village indigenous chickens. The study was carried out in five agro-ecological zones and seventy five households keeping indigenous chickens. Farmers were randomly selected and assessed on whether they understood Newcastle disease including knowing its local name and clinical signs manifested by the affected birds. Those who did not fit into the above category were excluded from further interviews. Data on management practices, incidence of diseases and risk factors associated with Newcastle disease outbreaks were collected using a questionnaire and analysed using statistical package. The prevalence rate of Newcastle disease was highest (93.8%) in the dry zone (Low midland 5) and lowest (50%) in cool wet zone (Lower Highland I). Newcastle disease outbreaks were significantly associated with the following factors namely: confinement of birds in all ecological zones except in lower midland 5 where most cases were reported without confinement; mode of disposal of infected birds, carcasses and poultry faecal matter; dry seasons in the dry zones just before the rains; wind conditions; short intermittent temperature changes and the restocking of farms with chickens from the markets (P<0.05). Dust storm was not significantly (P>0.05) associated with Newcastle disease outbreaks. The responses varied across the seasons and between the agro-ecological zones. In conclusion, the study has shown that several factors namely: confinement; cold or very hot temperatures; winds; introduction of market birds and disposal of manure and sick birds are major risk factors to occurrence of Newcastle disease in indigenous chickens. It is recommended that flock owners be educated on Newcastle disease transmission and prevention.