Salmonella in sheep in Iceland

In 1995 several outbreaks of food poisoning in humans occurred in Iceland, that were traced to salmonella contamination of singed sheep heads. This prompted us to study the prevalence of salmonella infection in sheep and to trace where and how infection might have occurred. Faecal, intestinal contents and tonsillar samples were collected in the spring and autumn from sheep on 50 farms in the southwestern part of the country, where salmonellosis had been detected and from 5 farms in the northwestern part of the country. All faecal samples from the southwest were negative, whereas samples from 3 farms obtained in the autumn in the northwest were positive. Tonsillae taken in the autumn were positive in sheep from 3 farms in the southwest and 2 in the northwest. Our results show that salmonella infection is rare in Icelandic sheep but healthy carriers my harbour the bacteria in tonsillae. Salmonella was not detected in drainage from slaughterhouses nor in singed sheep heads.