Vaccination trial of SPF chickens against the New castle disease using the original technique of a coated-millet vaccine from a thermotolerant drivative of the LaSota virus

Abstract

The thermotolerant variant A₃₀₀ of LaSota virus was used to vaccinate 4 week old specified pathogen-free (SPF) chickens by feeding them with virus coated-millet. With vaccine doses above 10⁶ EID₅₀/bird, HI antibodies developed and protection to challenge was seen 2 months after vaccination, while 100 % mortality occurred in the control groups. The PD₅₀ was estimated to 10^6.85 EID₅₀. This lyophilized vaccine intended for African village chickens can be kept at ambient temperature for at last 1 week up to 35°C. Other trials on a large scale are still needed to determine the potential of this vaccine in the field conditions of rural Africa.