Listeriosis in sheep. Isolation of Listeria monocytogenes from organs of slaughtered animals and dead animals submitted for post-mortem examination.

The udders from 13 culled ewes and liver, spleen, kidney, lung and brain from 15 lambs, 11 months old, were examined for the presence of Listeria monocytogenes (Lm) at slaughter. Lm was isolated from 1 of 13 udders, from 6 of the 15 brains and from 0–4 of the other organs from each of the 15 lambs. Internal organs from 68 sheep submitted for post-mortem examination were examined in the same way. Lm was isolated from 25 of these animals. Lm was isolated from the brain of 7 of 9 animals with encephalitis, and from 0–3 of the other 4 organs examined. Lm was also isolated from 10–20 % of the organs from animals with other diagnoses. Altogether 9 of 10 animals with encephalitis and 16 of 58 with other diagnoses (28 %) were found to harbour this organism.