Abstract
Newcastle disease virus (NDV) causes significant losses of poultry in Tanzania. Like in many African countries, the regular surveillance of NDV is important for the control of disease. The objective of this study was to determine seroprevalence of NDV in backyard poultry in Bahi and Njombe districts of Tanzania over the rainy (May) and dry (November) seasons in 2016. Using hemaglutination inhibition test, the overall seroprevalence was determined to be 26.8%. The significant differences in seroprevalence was between seasons ((higher (34.9%) in dry season, p < 0.0001)) and age ((higher (30.3%), p < 0.0001 in adult birds)). There were no significant differences in seroprevalence between the districts or sex. The higher levels of “protective” antibody titers were significantly associated with location; Njombe (RR 1.15), dry season (RR 1.08), and age; adult birds (RR 1.16), however the prevalence of these titers was not high enough to conclude any herd immunity among these flocks. This study therefore provides a brief insight of NDV disease dynamics in Tanzania. Future studies focusing on transmission, strain type, and monthly dynamics of NDV in backyard flocks will provide greater insight into the disease dynamics and allow new practical strategies to alleviate the effects of NDV for the smallholder farmers
Herd immunity to Newcastle disease virus in broiler flocks in Israel
