An outbreak of listerial meningo-encephalitis in sheep

An outbreak of ovine listerial meningo-encephalitis on sheep farms in eastern Gippsland, Victoria, during winter and spring 1978, is recorded. Cases were confirmed by histology of brain or by culture of Listeria monocytogenes from sheep on 21 farms. The morbidity rate in affected flocks ranged from 0.2% to 8.0%, and the case fatality rate was almost 100%. The peak incidence of disease followed a period of continuous heavy rain and flooding of grazing pasture, and the majority of affected flocks were located on poorly drained coastal sandy soil. There was evidence of concurrent debilitating disease in many of the cases submitted for laboratory confirmation of listeriosis.