Blackleg in cattle: A case report of fetal infection and a literature review

Abstract

Clostridium chauvoei causes blackleg in cattle. The disease has been reported worldwide, and although it can be prevented by vaccination, sporadic cases and occasional outbreaks still occur. We describe a case of blackleg in a 2-y-old, pregnant Gyr cow with in utero transmission to the fetus. The cow had characteristic gross and microscopic lesions of blackleg including widespread necrohemorrhagic and emphysematous skeletal and myocardial myositis, and fibrinous pericarditis. Her uterus contained a near-term, markedly emphysematous fetus with skeletal muscle and myocardial lesions similar to those seen in the dam. Histopathology of dam and fetal tissues revealed numerous gram-positive bacilli, many of them with sub-terminal spores, in multiple tissues. These bacilli were identified as C. chauvoei by immunohistochemistry. Anaerobic culture and fluorescent antibody tests performed on skeletal muscle from both the dam and fetus were positive for C. chauvoei, confirming a diagnosis of blackleg. Blackleg is a so-called endogenous infection, and the currently accepted pathogenesis involves ingestion of spores that are transported to muscle tissues where they lie dormant until anaerobiosis prompts germination. Germinating bacteria are histotoxic, producing severe, local necrosis and ultimately lethal toxemia. This model, however, has not been confirmed experimentally and also fails to explain some cases of the disease. A presumptive diagnosis of blackleg is based on clinical, gross, and histologic findings. Diagnostic confirmation necessitates the detection of C. chauvoei by culture, PCR, or immunodetection methods.

Financial impact of an outbreak of clinically diagnosed blackleg – a case study from Lao PDR

“…; Abreu et al . ). With concerns of that increasing climate variability may lead to more mass mortality events due to hypothermia (Khounsy et al .…”

“…; Abreu et al . ). In addition, over 60% of the mortality cases occurred in females rather than males, and in cattle rather than buffalo, although this apparent variation in susceptibility may be related to the fact that there are more cattle and females than buffalo and males per household (Nampanya et al .…”

“…Other virulence factors include the β ‐ and γ ‐toxins, DNase and hyaluronidase, respectively and it has been suggested that variations in expression of these toxins leads to variations in the characteristic lesions and degree of toxicity observed (Smith & Williams ; Sathish & Swaminathan ; Abreu et al . ).…”

“…C. chauvoei was discovered in 1887 and named after the French scientist, JBA Chauveau (Smith & Williams ; Abreu et al . ). BL occurs globally in ruminant populations, causing significant losses in livestock production from a disease causing lesions characterised primarily as myonecrosis, with high mortality, usually in animals of good condition and aged between 6 months and 2 years (Groseth et al .…”

“…; Abreu et al . ). It is considered that animals become infected by C. chauvoei spores ingested from contaminated soil (Smith & Williams ) and that infected animals mostly die rapidly’ although the sudden onset of clinical signs that may include lethargy, reluctance to move, recumbency, swelling and crepitus have been reported (Smith & Williams ; Groseth et al .…”