Bacteriological, molecular and histopathological evaluation of four vaccines’ protective role against caseous lymphadenitis in sheep

Abstract

The caseous lymphadenitis disease (CLA) due to Corynebacteriumpseudotuberculosis has worldwide distribution and indicates high prevalence in different countries. The bacterium has many pathogenicity factors; firstly, “phospholipase D”, an exotoxin virulence factor that enhances vascular permeability and facilitates bacterial transmission causing endothelial cell damage.The bacterium's exterior lipid cover is the second pathogenicity factor.This protects it from hydrolytic enzymes found in the phagocytes of the host, where the bacteria proliferate and then release after rupturing. Bacterial proliferation causes CLA abscesses, which are followed by attraction and the formation of an inflammatory response, which increases lymph flow and vascular permeability. The purpose of this study was to look atpostmortem findings, bacterial cultures, and histology of vaccinated sheep to see how well they were protected. On 15 male local sheep bread, four prepared vaccinations against C. pseudotuberculosis biotype 1 were tested. The animals were divided into 5 groups; four of various vaccines used and the fifthwere kept non-vaccinated. A live virulent strain of C. pseudotuberculosis was given to each group. Unvaccinated animals displayed CLA symptoms similar to those seen in spontaneously sick animals. Postmortem examination findings, standard bacteriological culture methods were used to isolate C. pseudotuberculosis, as well as tissue preparation for histopathological sections.