Rethinking the role of alpha toxin in Clostridium perfringens-associated enteric diseases: a review on bovine necro-haemorrhagic enteritis

Abstract

Bovine necro-haemorrhagic enteritis is an economically important disease caused by Clostridium perfringens type A strains. The disease mainly affects calves under intensive rearing conditions and is characterized by sudden death associated with small intestinal haemorrhage, necrosis and mucosal neutrophil infiltration. The common assumption that, when causing intestinal disease, C. perfringens relies upon specific, plasmid-encoded toxins, was recently challenged by the finding that alpha toxin, which is produced by all C. perfringens strains, is essential for necro-haemorrhagic enteritis. In addition to alpha toxin, other C. perfringens toxins and/or enzymes might contribute to the pathogenesis of necro-haemorrhagic enteritis. These additional virulence factors might contribute to breakdown of the protective mucus layer during initial stage of pathogenesis, after which alpha toxin, either or not in synergy with other toxins such as perfringolysin O, can act on the mucosal tissue. Furthermore, alpha toxin alone does not cause intestinal necrosis, indicating that other virulence factors might be needed to cause the extensive tissue necrosis observed in necro-haemorrhagic enteritis. This review summarizes recent research that has increased our understanding of the pathogenesis of bovine necro-haemorrhagic enteritis and provides information that is indispensable for the development of novel control strategies, including vaccines.

Silage fermentation—updates focusing on the performance of micro‐organisms

“…Clostridium perfringens type A has been associated with enteric diseases in ruminant and monogastric animals; although it is not common in silage, this micro‐organism has been isolated from alfalfa silage (Rossi and Dellaglio ) and can cause bovine necro‐haemorrhagic enteritis in young bovines (calves) (Goossens et al . ) and haemorrhagic bowel syndrome, a disease reported to be high in dairy cows (Elhanafy et al . ).…”

Clostridial Abomasitis and Enteritis in Ruminants

“…24 Alpha toxin likely acts in concert with additional virulence factors, resulting in intestinal mucosal damage and, in particular, the C perfringens toxin perfringolysin (theta toxin) seems to work synergistically with alpha toxin in calves. 25,26 Beta Toxin Beta toxin is produced by type B and C strains of C perfringens. The beta toxin gene (cpb) is encoded on a large plasmid and codes for a small polypeptide protoxin.…”

“…Enteritis caused by C perfringens type A is observed in calves, lambs, and kid goats. 1,3,10,25,30,47,50,64,65 Enteritis is generally acute and develops over a period of hours. Appetite is significantly decreased.…”

Enteric Immunity

“…34 Immunopathology is seen in protozoal diseases like cryptosporidia, where localized neutrophilia is enhanced in young animals [34][35][36] and also has been hypothesized as the major contributor to the lesions of C perfringens alpha toxin. 37 The proinflammatory anti-inflammatory mucosal response increases with Enteric Immunity: Happy Gut, Healthy Animal age and results in less disease. Neutrophils (see Fig.…”