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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #214410
Title: CLINICAL ASPECTS OF VETERINARY LISTERIOSIS

Author
item LARSON, DAVID - IOWA STATE VET LAB
item WILSON, ARACH - USDA-APHIS-VS
item Wesley, Irene

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/23/2007
Publication Date: 3/23/2007
Citation: Larson, D., Wilson, A., Wesley, I.V. 2007. Clinical aspects of veterinary listeriosis. In: Proceedings of the 16th International Symposium on Problems of Listeriosis, March 20-23, 2007, Savannah, Georgia. Available:http://ww.aphl.org/conferences/proceedings/pages/ISOPOLXVI.aspx.

Interpretive Summary: Most domesticated animal species are susceptible to infection with L. monocytogenes. The majority of infected animals appear clinically healthy but shed the pathogen in their feces. The clinical manifestations of listeriosis in livestock--encephalitis, abortion, and septicemia-- are illustrated with recent cases presented to the Iowa State University diagnostic laboratory. Ninety percent of these listeriosis cases were diagnosed as either bovine encephalitis or bovine abortion. Despite the large population of hogs in Iowa, no cases were identified in pigs. Differential diagnosis (rabies, transmissible spongiform encephalitis) is presented. Methods for identification in tissues (bacterial isolation, immunohistochemistry, Gram staining) are evaluated for sensitivity and specificity.

Technical Abstract: This invited presentation updates the clinical aspects of Listeria monocytogenes in food animals. It summarizes the epidemiology and diagnostic methods. Virtually all domesticated animal species are susceptible to listeric infection, with a large proportion of healthy asymptomatic animals shedding L. monocytogenes in their feces. Sheep, goats, cattle and less frequently pigs and rarely chickens succumb to infection. Although the majority of infections are subclinical, listeriosis in animals can occur either sporadically or as epidemics affecting up to 15% of the herd. The clinical manifestation of listeriosis in livestock--encephalitis, abortion, and septicemia-- are illustrated with actual cases presented to the Iowa State University diagnostic laboratory. From 2000-2007, listeriosis cases (n ~ 200) were from bovine (87%), ovine (9%), goats (2%), a llama and a horse (0.4% each). Ninety percent of these listeriosis cases were diagnosed as either bovine encephalitis or bovine abortion. Bovine listeriosis is the most frequently diagnosed neurological disease and is the most common cause of bacterial infection of the central nervous system in adult cattle worldwide. Differential diagnosis (rabies, transmissible spongiform encephalitis) is presented. Methods for identification in tissues (bacterial isolation, immunohistochemistry, Gram staining) are evaluated for sensitivity and specificity.