Newcastle disease virus and antibody levels in matched sera, ovules and mature eggs of indigenous village hens
In this study, one hundred and thirty three non - vaccinated village hens in lay were tested for carriage of Newcastle disease virus and presence of antibody against the virus in sera, ovules and eggs. Blood was obtained from the hens through wing venipuncture while matched ovules and mature eggs were taken from the oviducts. Cloacal and oropharyngeal swabs
were collected from each hen for virus isolation. Haemagglutination inhibition assay was performed for all sera and egg yolk samples. Protective serum antibody titres of ≥3 (log2) were recorded in 5.3% of the naturally exposed, indigenous village hens. Antibody titers to Newcastle disease virus in the yolks were higher than in their sera (230.08 ± 40.05; 1.56 ± 0.74 for egg yolk and sera, respectively) (P<0.05). The mature egg yolks had significantly higher titres of antibodies as compared to the ovules (P<0.05). Sera and egg yolk antibodies were positively correlated (r = 0.50). Newcastle disease virus was isolated in 3.0% of the hens that were also sero - negative. The presence of Newcastle disease virus antibodies in egg yolks and Newcastle disease virus isolation in seronegative hens, indicate previous natural exposure to the virus, hence viral endemicity in the area.
Keywords: Newcastle disease, egg yolk, nonvaccinated, village chickens