Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 20, 2000
Publication Date: N/A
Interpretive Summary: Raccoons are widespread throughout North America. They are highly adaptable omnivores and have managed to survive and increase their numbers in many urban and suburban areas. Since they share our immediate environment, they have been used in the past as monitors of zoonotic diseases and environmental contamination. However, since there is paucity of published information on parasites and diseases of raccoons, documentation of naturally occurring diseases and lesions in this species is of paramount importance. In the present study, we examined large intestines of 21 raccoons (11 wild caught and 10 laboratory confined) for the presence of intestinal spiral bacteria. Microscopic examination showed presence of spiral shaped organisms deep within the glands in the intestines of 16 raccoons (76% prevalence). All laboratory confined, group-housed raccoons were found with the organisms; whereas, only 6/11 (55% prevalence) live-trapped raccoons were positive for the bacteria. Due to the absence o lesions in the intestines, we conclude that these organisms are normal intestinal flora in raccoons.
Technical Abstract: The large intestines of 21 raccoons (11 wild caught and 10 laboratory confined) were examined for the presence of intestinal spirochetes. Light microscopy of hematoxylin and eosin (HE) and Warthin Starry stained sections showed the presence of spiral shaped organisms deep within the lumina of intestinal glands at the ileo-colonic junction of 16 raccoons (76% prevalence). All laboratory confined, group-housed raccoons were foun with the organisms; whereas, only 6/11 (55% prevalence) live-trapped raccoons were positive for the spirochetes. The organisms were free in the glandular lumina and there were no microscopic lesions. Two types of spirochetes were identified in the colonic glands: a slender spirochete 10-13 (m in length, 0.3 (m in diameter and possessing long, thin tapered ends, and a larger, regularly waved spiral organism (0.5 (m in diameter). The slender spirochete did not resemble any of the known spirochete genera and failed to grow on media used to propagate oral treponemes and members of the Brachyspira genus.