[The distribution and persistence of Campylobacter spp. in chickens].

At the end of the production period, 29 layers each from 70 different flocks were examined for the occurrence of campylobacters in their caecal contents. All flocks were found campylobacter positive. Up to 20 individuals of 13 flocks and 21 to 29 birds of 57 flocks were carriers of Campylobacter spp. Material of the liver was additionally cultured from birds of 36 flocks. The isolation of the organism from livers was possible only from 1 to 6 birds of 16 flocks. In two experiments, chickens were infected at an age of 4 weeks with campylobacter strains inducing different excretion rate. The birds were infected again with a further campylobacter strain at 10 weeks of age. Birds at the same age which were not infected before, served as control. After this superinfection, the excretion of the organisms occurred at the same rate in all groups and did not depend on the strain chosen for the first infection. After an additional second superinfection in the second experiment, the period of excretion of the organism at a high rate was diminished.