Vaccine Trails Against Bovine Farcy

Abstract

The present study was designed to develop and evaluate a live vaccine against bovine farcy. Mycobacterium farcinogenes (M. farcinogenes) strain A20, was passaged in a set of guinea pigs. The attenuated strain produced no lesions neither at the site of inoculation nor in any other organ of the tested guinea pigs. The organism, which was reisolated from the guinea pigs, was labelled as M. farcinogenes A24. Another experiment was carried out in guinea pigs to determine the degree of protection following the vaccination with M. farcinogenes A24. Guinea pigs were divided into two groups. Vaccinated and non-vaccinated groups. At the end of the 9th week, the challenge infection was performed using a freshly isolated M. farcinogenes SD117, which was isolated from a cow with bovine farcy. Ninety two percent (92%) of guinea pigs from vaccinated group showed no nodular lesions, whereas all the non-vaccinated guinea pigs showed visible nodular lesions. Eleven calves were used for vaccine trials in bovine. The calves were divided into three groups: vaccinated group (n=8), non-vaccinated group (n=2) and control group (n=1). Seventy five percent (75%) of the vaccinated calves showed no lesions following the challenge infection while all of nonvaccinated calves showed the nodular lesions at site of inoculation. ELISA readings among the vaccinated and non-vaccinated guinea pigs showed that the mean optical densities at 450 nm were 0.15 and 0.05, respectively.