Young and older suckling piglets with colibacillosis

Colibacillosis is the most common cause of diarrhoea in piglets before weaning. An extreme proliferation of enterotoxin-producing E. coli strains ( ETEC ) and their invasion of the upper part of the small intestine results in E. coli diarrhoea, together with an 1000- to 10000-fold increase in bacteria. In most cases of diarrhoea and mortality among suckling piglets enterotoxic E. coli strains are involved. The E. coli attach themselves, helped by their fimbriae, to special receptors on the intestinal wall and start releasing enterotoxins. These toxins trigger an enormous increase of secretion of water, which exceeds the resorption capacity of the intestines, causing watery diarrhoea. For example, the serotype O149 is primarily associated with colibacillosis. The fimbriae F4 or F18 are present in almost all cases. E. coli strains with the fimbriae-types F5 and 6 and F41 are the ones that particularly cause colibacillosis in neonatal piglets.

The clinical signs of colibacillosis are yellow, watery diarrhoea and dehydration , involving depletion of electrolytes. The piglets begin to shiver and usually have sunken flanks, a rough haircoat, and are depressed with a hanging tail. The piglets have yellowish smears over their rear ends and the underlying skin here can be reddened. Despite continued sucking, the dehydration increases rapidly. Without treatment and rehydration, mortality is around 50% for young sucking piglets, but lower in older sucking piglets. Diarrhoea occurs in the first 48 hours of life; almost always the entre litter is affected.