E. Coli O103 enteritis in weaned rabbits. Vaccination trials

Abstract

Digestive colibacillosis in weaned rabbit is an epizootic enteritic syndrome, with mortality rates up to 30 %, which occurs frequently in French industrial rabbit-fattening farms. It is associated with the colonization of the distal ileum and caecum by Escherichia coli strains belonging, in France, mostly to the 0103 serogroup and to rhamnose negative biovars. A new proteic adhesin of m.w. 32,000, which allows this colonization, has been recently described in these strains. Antibiotics are ineffective in controlling the disease. On the contrary, oral vaccination, which stimulates local immunity at the digestive level, is efficient in the prevention of the illness. In our hands, a formalin-killed vaccine, prepared from a culture of an O103 strain in a medium which favours the expression of the adhesin and given per os in a 4-days schedule to young rabbits at weaning, completely protects the animals against a virulent challenge and allows a quick elimination of the challenge O103 strain from their digestive tract. This original prophylactic method will improve as information on the infection and the causal bacterial strains is documented.