[Prevention of salmonella infections in laying hens by vaccination]

After multiple infections with S. enteritidis in humans and demonstration of S. enteritidis in egg products, S. enteritidis (lysotype 6, plasmid profile 40) could be isolated from organs of hens, anal swab tests of chicken, liquid manure, egg shells and non pasteurized egg contents. Because of the largeness of the hen farm prophylactic vaccinations seemed to be advisable additionally to improvement of the management and hygiene. A vaccine registered in 1987 for use in pigeons and water fowl "Zoosal oral Dessau" was used. As a test three were vaccinated three times and artificially infected. Cross immunity against S. enteritidis could be demonstrated. In October 1987 all chicken of the farm were vaccinated three times at the age of 4, 6 and 7 weeks; random samples were tested for immunity and cross immunity. Until the end of the laying period immunity against S. typhimurium could be proven in 98% of the hens, against S. enteritidis in 95%.