Epidemiology and clinicopathologic manifestations of newcastle disease in Nigerian local chickens

A retrospective study of Newcastle disease (ND) in local chickens diagnosed in the Avian Ambulatory Unit of the Veterinary Teaching Hospital, Ahmadu Bello University, Zaria, Nigeria, from January 1978 to December 1997 was conducted. The incidence rate was higher in the dry season with 183 cases (68.4%) against 97 cases (34.6%) in the rainy season out of a total of 280 cases. The study suggested that ND was higher during the dry months of the year possibly because of the harmattan, cold, stress and high wind velocity. The rate was higher in the young with 58 cases (20.7%) against 34 (12.1%) in the adult. There was a statistically significant difference (p < 0.05) between ND cases in the dry season and in the rainy season. The Doyle’s form of ND had the highest incidence with 106 cases against the Beach’s form with 36 cases, the Beaudette’s form with 6 cases, and the Hitchner’s form that had no case. It was therefore recommended that in producing vaccines against ND, antigens that can stimulate production of a high antibody response against the virulent Doyle’s form should be used.