Production and trials of inactivated oil-emulsion Newcastle disease vaccines in Ethiopia

Abstract

Two experiments were undergone at the National Veterinary Institute, Debre Zeit, Ethiopia, to test the feasibility of oil-emulsion Newcastle vaccines. The antigen chosen was the LaSota strain. In a first experiment, the antibody response seemed proportional to the quantity of antigen incorporated into the vaccine. In a second experiment, a vaccine prepared with pure allantoic fluid, as aqueous phase, proved efficient enough to elicit antibody titers ranging from 1/250 to 1/80 from the beginning up to the end of the year following the vaccination of a commercial flock of layers. For comparison purpose, chickens from specific pathogen-free origin had titers reaching 1/512 despite a vaccine storage time of 6 months at 4 °C.