RUMINANTS

Yersinia pseudotuberculosis enterocolitis and lymphadenitis in a goat

Maria Spinato, John Hancock, Durda Slavic

A 2-y-old Boer goat doe died following a short bout of diarrhea. During an on-farm postmortem, significant external findings included moderate dehydration, sunken eyes, and liquid feces soiling the hind end. The most remarkable internal lesions were depleted fat stores and marked enlargement of mesenteric lymph nodes (Fig. 1). Formalin-fixed and fresh tissue samples were submitted to the Animal Health Laboratory for testing, as per the small ruminant adult mortality project protocol.

Histologically, the most remarkable lesions included bacterial microabscesses within sections of mesenteric lymph node (Fig. 2), erosive and necrotizing enterocolitis accompanied by proliferation of large bacterial colonies (Fig. 3), and multifocal necrotizing hepatitis typified by colonies of bacterial coccobacilli surrounded by a broad rim of degenerate leukocytes. Heavy (3+) growths of Yersinia pseudotuberculosis were isolated from cultures of jejunum and a swab of mesenteric lymph node.

This doe died of Yersinia pseudotuberculosis septicemia; localizing lesions predominantly involved the small intestine (diarrhea), mesenteric lymph nodes (lymphadenopathy), and liver. This organism is a member of the gastrointestinal flora of multiple species of animals, and infection is thought to be fecal-oral after the ingestion of food or water suspected to be contaminated by wildlife, most commonly rodents and birds.

The name “pseudotuberculosis” describes the tuberculoid appearance of granulomas in affected tissues. Clinical disease in domestic species usually affects only individual animals. Mastitis and abortion have also been reported in goats. Two cases of ovine abortion caused by Y. pseudotuberculosis were diagnosed at the AHL this past winter. In other geographic regions, such as California, cases of enterocolitis and/or abortion have been reported in cattle, llamas, water buffalo, and sheep. This organism is a documented cause of food-borne illness in humans, and outbreaks have occurred following ingestion of contaminated milk, meat, fresh vegetables, and water.   AHL

Reference

Giannitti F, et al. Yersinia pseudotuberculosis infections in goats and other animals diagnosed at the California Animal Health and Food Safety Laboratory System: 1990-2012. J Vet Diagn Invest 2014;26:88-95.

Figure 1: Markedly enlarged mesenteric lymph nodes. (stars).

Figure 2: Mesenteric lymph node containing bacterial microabscesses (arrow) due to Y. pseudotuberculosis.

Figure 3: Small intestine revealing mucosal erosion and multiple colonies of Y. pseudotuberculosis (arrows).