Comparison between a live and an inactivated vaccine against Newcastle disease in village chickens. A field study in northern Malawi

A total of 156 chickens in two villages in Malawi were marked and sampled. One hundred and fifteen of these were vaccinated against Newcastle disease immediately after blood sampling, using the V4 heat-resistant strain applie d by eye-drop in one village and the inactivated Newcavac vaccine in the ot her village. A second blood sample was collected 4 weeks after vaccination. The samples were examined using an indirect ELISA test kit. The titre grou p median ranged from 2 to 3 before vaccination. Both vaccines led to a posi tive immune response. Newcavac induced higher and more homogeneous titres c ompared with the V4 vaccine. There was also an increase in the median of th e control group where V4 live vaccine had been applied. The differences bet ween the median titres induced by V4, Newcavac and controls were statistica lly significant.