Pathogenicity of Newcastle Disease Virus Isolated from Ethiopia

Abstract

Newcastle disease represents an enormous problem for African breeders, and country-specific fears and economic exchanges complicate  its elimination and control. Slow laboratory diagnosis creates additional delays during initial epidemic discovery. To address  these concerns, researchers undertook a study in Ethiopia to examine the impact of the circulating Newcastle disease virus on chicken  farms. The aim of the study is to identify the virus from likely outbreak cases, confirm its pathogenicity, and evaluate its effects on  vaccinated and uninfected chicks Forty chicks were separated into 02 groups and exposed to 02 virus samples at the National Veterinary  Institute in Bishoftu, Ethiopia. The isolated viruses were classified as velogenic, with the BOG strains scoring 1.67 and the HAR strains rating 1.55. Immunized chicks demonstrated high herd immunity, while single immunization failure was observed. In the challenged  group, the death rate was 55%, with all 20 unvaccinated chicks dying from the sickness, whereas just 2 out of 20 vaccinated chicks were  afflicted. Statistical analysis showed that the virus produced general inflammation, which was more common in the BOG group (87.50%)  than in the HAR group (12.50%). Vaccination significantly reduced clinical signs and gross lesions, such as irritation in multiple organs. The study showed the persistence of velogenic Newcastle disease virus strains in Ethiopia and the importance of vaccination. The findings  have improved our understanding of the disease's physiopathology and provided vital information for responsible authorities  to implement early intervention techniques.