[Detection of Salmonella enteritidis in suspected flocks of laying hens]

60 birds and environmental samples from 41 suspect flocks (S. enteritidis in faeces or litter, positive serology, close connection with human cases) were investigated to define material and minimal number of birds for detection of infection. S. enteritidis was found in 26/41 (63%) flocks with marked differences in prevalence. S. enteritidis was isolated from ovary (96% of positive flocks), oviduct and liver (87%), spleen (83%), caecal contents (50%) and faeces from the litter floor (57%), but never from egg shells and membranes. As a consequence of this study the bacteriological examination of birds is highly recommended.