A REVIEW OF LISTERIA-MONOCYTOGENES AND LISTERIOSIS

Following the initial isolation and description in 1926 Listeria monoc ytogenes has been shown to be of world-wide prevalence and is associat ed with serious disease in a wide variety of animals, including man. O ur knowledge of this bacterial pathogen and the various forms of liste riosis that it causes has until recently been extremely limited, but r ecent advances in taxonomy, isolation methods, bacterial typing, molec ular biology and cell biology have extended our knowledge. It is an ex quisitely adaptable environmental bacterium capable of existing both a s an animal pathogen and plant saprophyte with a powerful array of reg ulated virulence factors. Most cases of listeriosis arise from the ing estion of contaminated food and in the UK the disease is particularly common in ruminants fed on silage. Although a number of forms of liste riosis are easily recognized, such as encephalitis, abortion and septi caemia, the epidemiological aspects and pathogenesis of infection in r uminants remain poorly understood. The invasion of peripheral nerve ce lls and rapid entry into the brain is postulated as a unique character istic of its virulence, but relevant and practical disease models are still required to investigate this phenomenon. This review offers an u p to date introduction to the organism with a description of virulence determinants, typing systems and a detailed account of listeriosis in animals. Experimental and field papers are reviewed and further secti ons deal with the diagnosis, treatment and control of listeriosis in a nimals. A final part gives an overview of listeriosis in man.