Abstract
Although a case of human listeriosis has recently been reported in Saudi Arabia, the disease has not been reported in animals to date. The authors describe an outbreak of septicaemic listeriosis in sheep, which occurred during winter. Adult animals and pregnant ewes were principally affected, with a morbidity rate of 7.1% and a mortality rate of 2.4%; no abortions were recorded during the outbreak. Clinical signs included inappetence, weakness, fever, respiratory distress, keratoconjunctivitis and compulsive circling. Listeria monocytogenes was isolated in pure culture from affected sheep. Pathological findings indicated septicaemic listeriosis with encephalitis. Hygienic measures and antibiotics were successful in treating the rest of the flock. Aspects of the outbreak and public health implications are discussed.