Detection of Clostridium perfringens bacterium in the clinical specimens from blackleg calves: a report of two cases

This paper describes the first report involving two cases of blackleg caused by Clostridium perfringens Type D as a main causative agent with an emphasis on clinical symptoms, the bacteriological and pathological analyses, and molecular detection of the pathogens by PCR method. Two calves of a flock were presented to the veterinary hospital of Shahid Bahonar University of Kerman, Iran. Both calves died suddenly and showed considerable muscle crepitation in the posterior limb. Severe necrosis of thigh muscles in both hind legs, which had caused dark discoloration of tissue with metallic sheen, large amount of thin sanguineous exudates, and numerous gas bubbles in the underlying tissues were evident during necropsy. Histopathological examination revealed extensive degeneration, coagulative necrosis of muscle fibers, severe edema, and small to large cavities due to emphysema between myofibers. Based on these findings, a definitive diagnosis of blackleg was supported. In bacteriological examination, C. perfringens was isolated from muscle and liver samples, which was reconfirmed through morphological and biochemical studies of the isolated strains. Molecular typing of isolated bacteria by multiplex PCR showed that the C. perfringens belongs to Type D of this bacterium. Overall, based on these observations, we propose that the C. perfringens Type D’s toxins are not only able to target the alimentary tract; they can also produce the lesions in other body parts especially in muscles. Whereas the blackleg outbreaks have been commonly reported sporadically in the endemic regions of Iran, identification of C. perfringens Type D, as a main causative agent of blackleg, is a novel finding in veterinary medicine.