Yersinia pseudotuberculosis septicemia in a striped skunk

Photo credit: Dan & Lin Dzurisin (Wikimedia Commons)

In late January, 2015 the SPCA was called to remove an adult male skunk from a residential yard in Vancouver BC. The skunk was found to be shaking and immobile. He was taken to a wildlife rehabilitation centre for examination and was found to be hypothermic, lethargic, hypersensitive to stimuli but unaware of surroundings. Symptomatic treatment was administered but he died a day later and was submitted to the Animal Health Centre in Abbotsford BC for necropsy.

On necropsy, the skunk was in good body condition (weight 2.6 kg) with acute gastrointestinal hemorrhage and meningeal congestion. Roundworms were present in the gastrointestinal tract.

Histopathology revealed large colonies of gram negative bacterial bacilli in multiple organs including kidney, liver and lung. There was mild to moderate membranous glomerulonephritis with protein present in tubules. Molecular testing for Aleutian disease virus (ADV) was positive in organs and brain, negative for influenza in nasal, lung and intestinal samples and negative for Leptospira spp on kidney. Rabies immunohistochemistry on brain was negative. Although the skunk was positive for ADV, there was no definitive evidence of Aleutian disease (AD). The changes in the kidney were however suggestive of possible early development of AD. Gastrointestinal hemorrhage was attributed to stress. Bacterial workup isolated heavy growth of Yersinia pseudotuberculosis from multiple organs. Septicemia due to Y. pseudotuberculosis was diagnosed as the cause of death. It is unclear how this skunk came to develop septicemia as no significant underlying disease process which might act as a portal for or predisposition to the infection was identified.

Y. pseudotuberculosis is a rare cause of disease in animals. The bacterium is however found in a wide range of animal reservoirs including wild mammals, rodents, wild birds, dogs, cats, horses and cattle. Guinea pigs and farmed deer may be the most commonly diagnosed animals with the disease. The bacterium has zoonotic potential causing septicemia, gastroenteritis and mesenteric lymphadenitis in humans, providing yet another reminder to employ effective personal protective measures when handling animals, especially wildlife. In humans, the disease is usually food-borne and related to contaminated vegetables.

Submitted by Ann Britton, BC Animal Health Centre