[Contribution to the aetiology and epidemiology of botulism in broiler chickens (authors transl)].

The second outbreak of botulism in broiler chickens diagnosed in the Netherlands is reported. In this case, the source of botulinum toxin was positively located. Despite the fact that the owner had emphatically assured that all sick and dead broilers had been carefully removed, several carcasses of broilers, almost unrecognizable at first sight, were found to be present in the litter covering the floor, particularly at the rear of the fowl house. The concentration of toxin in the carcasses in the area surrounding this source of infection averaged well over 1,000,000 LD50 per gram of tissue. This is more than sufficient to account for the outbreak of botulism as the oral MLD of the strain of Cl. botulinum type C isolated in previous studied had been found to be well over 4,000,000 LD50 per kg of body weight for chickens, the oral MLD of the strain of Cl. botulinum type C isolated in the second outbreak being found to be 2,000,000 LD50 per kg. of body weight. In discussing the origin of the infection, attention is finally drawn to the possible relationship with the fact that botulism has become increasingly common among waterfowl in the Netherlands since 1970.