The vaccination indices of Newcastle disease (ND) in chickens in Aba and Umuahia towns of Abia state were studied alongside their corresponding antibody status. A total of 296 sera samples were collected from 74 chicken farms. A Haemagglution inhibition (HI) test was conducted to determine the ND virus serum antibody levels. Open and closed-ended questionnaires were administered to staff on the farms selected randomly in the study areas. Information on vaccine types, origin, administering personnel, revaccination interval, and records of ND outbreaks was collected. Whereas 68.9% of the farm carried out vaccination on their own, 27.0% and 4.1% of the vaccination were done by veterinarians and animal health scientists Farms in Aba and Umuahia had average geometric mean titres (GMT) of 166.32 and 100.33, respectively. Approximately 87% of the farms had protective immunity (GMT >8 or log23) against ND. Chickens aged 1-3, 4-8, 9-16, 17 weeks and above had average GMTs of 64.00, 76.99, 283.7 and 197, respectively. Post-vaccination antibody titres were 128.92, 110.63, 52.07 and 43.65, after 1 week, 2-3 weeks, 4 weeks, and above 4 weeks, respectively. Indigenous ND vaccines had an average GMT of 182.55, while foreign ND vaccines had a GMT of 120.82. The Result showed that 77% of farmers used foreign vaccines whereas 23% used indigenous vaccines. On vaccination interval, 40.5% revaccinated for ND every three weeks, 21.6% monthly, 8.1% bi-monthly and 29.7% revaccinated when necessary. About 54% of farmers reported previous ND occurrence. This study identified high seroprevalence of ND antibodies in the flock studied and indicated a high level of awareness and adherence to NDV vaccination among the farmers in the study area. The local vaccines elicited better immunogenic responses than their foreign counterparts. We, therefore, recommend that usage of the local vaccines be adopted, and revaccination is done before a month interval.
Key words: Newcastle disease, Vaccination, Immune response, Haemagglution inhibition, Geometric mean titre
|
