Salmonella Litchfield as a cause of an outbreak of salmonellosis in a herd of cattle

Salmonella Litchfield was isolated by the bacteriological examination of faecal samples from two febrile cows with diarrhoea. The herd was subsequently sampled on the basis of the likely prevalence of infection. As a result, S. Litchfield was detected in 17 of 44 faecal samples examined. A herd-specific vaccine was applied intranasally three times at one week intervals to all animals in the herd. The vaccination for calves was repeated, for a fourth time. Three weeks after the administration of the vaccine no shedding, animals were detected in the herd. Sparrows were considered as the most likely source of infection.