Effect of vaccination on transmission characteristics of highly virulent Newcastle disease virus in experimentally infected chickens.

Effect of vaccination on transmission characteristics of highly virulent Newcastle disease virus in experimentally infected chickens. Avian Pathol. 2014 Aug 8;:1-25 Authors: Fentie T, Dadi K, Kassa T, Sahle M, Cattoli G Abstract An experimental study was conducted to evaluate the effect of vaccines produced in Ethiopia from world-wide used vaccine strains on the transmission characteristics of velogenic Newcastle disease virus (NDV) field strain after different vaccination schemes. Birds were vaccinated by Hitchner B1 (HB1), La Sota, or I-2 via the intraocular and intranasal routes. Vaccine and challenge viruses induced high antibody levels, both in inoculated and contact birds. Prime-boost vaccination protected birds against morbidity and mortality and significantly reduced the incidence of viral shedding from chickens compared to single vaccinated and unvaccinated birds. Protection from disease and mortality was correlated with the presence of positive antibody titers (>4 log2) at day of challenge. Most of the unvaccinated and in-contact birds excreted the virus and showed high level of antibody titers indicating the high infectivity of the challenge virus. The detection of the challenge virus in most of vaccinated birds demonstrated that the tested vaccination protocols cannot fully protect birds from viral infection, replication and shedding, and vaccinated-infected birds can act as a source of infection for susceptible flocks...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research