AN INVESTIGATION OF THE EPIDEMIOLOGY OF NEWCASTLE DISEASE IN VILLAGE CHICKENS IN BAUCHI STATE NIGERIA
Newcastle disease (ND) is considered as a major constraint to village chicken production in Africa. A study on the epidemiology of ND in village chickens was conducted in nine communities randomly drawn from nine Local Government Areas (LGAs) in Bauchi State to asses: the importance of NDto village chicken farmers using the participatory epidemiological tools; the prevalence of ND from monthly disease reports, the prevalence of ND virus (NDV) and seroprevalence of ND; andacceptance among farmers of ND vaccination and its benefits.
A sixty Monthly Disease Reports (June 2010-May 2015) submitted by the eight Area Veterinary Offices covering the studied communities were examined at the office of the Director Veterinary Services Bauchi State for cases of ND disease in poultry. Staff from the Veterinary Department was assigned the duty of inviting farmers in each community for a focus group discussion (FGD) to assessthe importance of ND among the common diseases of village chickens in their community.
Participants of FGDs also selected eight households (HHs) in each community. From these HHs samples of blood and cloacal swabs for detection and determination of prevalence of antibodies and antigen of ND virus (NDV) were collected; chickens were vaccinated against ND to assess acceptance and benefit of vaccination. Also, volunteering members from these HHs answered questionnaire on village chicken management. Haemagglutination inhibition test (HIT) was used to detect ND antibodies from sera extracted from the blood collected from village chickens. Conventional Reverse Transcriptase Polymerase Chain Reaction was used to detect NDV.
Cloacal swabs that tested positive for ND were inoculated into 9-11 day old embryonate chicken eggs to isolate NDV. The prevalence of reported cases of ND in poultry was 11.6%. Newcastle disease was mostly reported during the cold season (October-March) with the highest seasonal index of 44.4% and an odds ratio of 6.6 in November. The proportional piling scores for ND in Chinade was 146/249 (69.9%), in Jalam 35/105 (32.4%), in Udubo 183/261(70.1%), in KafinMadaki 149/244 (61.1%), in Gongoro 80/183 (43.7%), in Dass 175/270 (64.8%), in Kutaru 126/243 (50.8%) and in Toro 173/288 (60.1%).
The pair wise ranking score for ND in Chinade was 4/5, in Jalam 5/6, in Udubo 5/6, in KafinMadaki 6/7, in Gongoro 4/5, in Dass 3/4, in Kutaru 5/6 and in Toro 4/5. Most of the respondents 71 (98.6%) had experienced outbreak of ND in their flock within the last six months with greater than 50% mortality of 54 (75%) chicken during the cold season. Vaccination against ND was not practiced by any of the respondents. The seroprevalence of ND was 36.4%;and the prevalence of NDV was 29.9%.
Three isolates (3/20; 15%) were obtained from cloacal swabs of chickens from Toro. Vaccination against ND was first carried out on 1139 village chickens in 72 HHs and the second vaccination was carried out on 814 chickens in 54 of the 72 HHs. Rejection of vaccination was experienced in 8 HHs (8/72; 11.11%). Additional ND vaccines were given to 746 chickens in 64 HHs that were neighbours of the initial participants.
A proportional piling scores given by 68 participants was 100% (340/340 beans shared) for acceptance of vaccination against ND, while, a score of 92.7% (338/365 beans shared) was given in favour of ND vaccine being beneficial to farmers of village chickens. The study concludes that ND is an important disease of village chickens that is widespread and cannot be controlled by the current management practices. Vaccination of village chickens against ND was accepted and beneficial to farmers.
The study recommends characterization of local strains of NDV by National Veterinary Research Institute, Vom; prioritization of ND by Bauchi State for state wide immunization and routine vaccination of village chickens against ND by farmers for an improvement in village chicken production.