Enzootic outbreak of necrotic gastritis associated withClostridiumperfringensin broiler chickens

Clinical morphological investigations were carried out in a flock of 22,000 Ross 308 broiler chickens at the age of 38 days that experienced a sudden increase in mortality rates. Morbidity and mortality rates were followed and gross anatomical examination of 150 bodies (7%) of all 1541 dead chickens was performed. In all necropsied birds, without exception, the typical macroscopic lesions were observed only in the gizzard. Focal or diffuse pseudomembranous deposits were found subcuticularly and on the gizzard mucous coat. Microscopically, hyalinization, desquamated epithelial cells and single foci of microorganisms were present among the formed pseudomembranes. Among the fibrin networks of coagulated exudate, a single bacilli were detected. Clostridium perfringens was isolated from all gastric samples investigated. Polymerase chain reactions were positive for alpha-toxin and negative for beta-toxin and beta(2)-toxin.