C. Manteca

A role for the Clostridium perfringens β2 toxin in bovine enterotoxaemia

Abstract Non-enterotoxigenic type A Clostridium perfringens are associated with bovine enterotoxaemia, but the α toxin is not regarded as responsible for the production of typical lesions of necrotic and haemorrhagic enteritis. The purpose of this study was to investigate the putative role of the more recently described β2 toxin. Seven hundred and fourteen non-enterotoxigenic type A C. perfringens isolated from 133 calves with lesions of enterotoxaemia and high clostridial cell counts (study population) and 386 isolated from a control population of 87 calves were tested by a colony hybridisation assay for the β2 toxin. Two hundred and eighteen (31%) C. perfringens isolated from 83 calves (62%) of the study population and 113 (29%) C. perfringens isolated from 51 calves (59%) of the control population tested positive with the β2 probe. Pure and mixed cultures of four C. perfringens (one α+β2+, one α+enterotoxin+ and two α+) were tested in the ligated loop assay in one calf. Macroscopic haemorrhages of the intestinal wall, necrosis and haemorrhages of the intestinal content, and microscopic lesions of necrosis and polymorphonuclear and mononuclear cell infiltration of the intestinal villi were more pronounced in loops inoculated with the α and β2-toxigenic C. perfringens isolate. These results suggest in vivo synergistic role of the α and β2 toxins in the production of necrotic and haemorrhagic lesions of the small intestine in cases of bovine enterotoxaemia. However, isolation of β2-toxigenic C. perfringens does not confirm the clinical diagnosis of bovine enterotoxaemia and a clostridial cell counts must still be performed.

Morbillivirus in common seals stranded on the coasts of Belgium and northern France during summer 1998

Sixteen common seals (Phoca vitulina) were stranded on the Belgian and northern French coasts during the summer of 1998. Eleven (10 pups and one adult) were sampled for histopathological, immunohistochemical, serological, bacteriological, parasitological and virological investigations. The main gross findings were severe emaciation, acute haemorrhagic enteritis, acute pneumonia, interstitial pulmonary emphysema and oedema, and chronic ulcerative stomatitis. Microscopical lung findings were acute to subacute pneumonia with interstitial oedema and emphysema. Severe lymphocytic depletion was observed in lymph nodes. Severe acute to subacute meningoencephalitis was observed in one animal. Specific staining with two monoclonal antibodies directed against canine distemper virus (cDv) and phocine distemper virus was observed in a few lymphocytes in the spleen and lymph nodes of three seals. Anti-cDv neutralising antibodies were detected in sera from six animals. Seven of the seals were positive by reverse transcriptase- PCR for the morbillivirus phosphoprotein gene. The lesions observed were consistent with those in animals infected by a morbillivirus, and demonstrated that distemper has recently recurred in North Sea seals.