Susceptibility of Raccoons (Procyon Lotor) to Infection With Mycobacterium Bovis

Abstract

Tuberculosis due to Mycobacterium bovis infection is endemic in white-tailed deer (Odocoileus virginianus) in the northeastern portion of the lower Michigan peninsula (USA). Various wild carnivores and omnivores, including raccoons (Procyon lotor), are infected with M. bovis within the endemic area. To investigate the pathogenesis of tuberculosis in raccoons and the likelihood of M. bovis transmission from infected raccoons to other susceptible hosts, we experimentally inoculated raccoons with single oral doses of M. bovis (ranging from 30 to 1.7 ϫ 10 5 colony forming units [CFU]), five daily oral doses of M. bovis (ranging from 10 to 1 ϫ 10 5 CFU), or a single intravenous (IV) dose of 1 ϫ 10 5 CFU of M. bovis, from November 1998 through December 2000. Granulomatous lesions consistent with tuberculosis, or tissue colonization with M. bovis, were seen in one of five raccoons in the single low oral dose group, one of five raccoons in the multiple low oral dose group, two of five raccoons in the multiple medium oral dose group, five of five raccoons in the multiple high oral dose group, and five of five raccoons in the IV inoculated group. In orally inoculated raccoons, lesions were most common in the tracheobronchial and mesenteric lymph nodes and lung. Excretion of M. bovis in saliva or nasal secretions was noted in all IV inoculated raccoons and two of five multiple low oral dose raccoons. Mycobacterium bovis was not isolated from urine or feces from any experimentally inoculated raccoons. The need for multiple large oral doses to establish infection, and the low number of orally inoculated raccoons that excreted M. bovis in nasal secretions or saliva, suggest that widespread tuberculosis among raccoons is unlikely.

Raccoons in Europe: disease hazards due to the establishment of an invasive species

“…Compared with other species like ferrets, in which one single oral dose resulted in lesion development and isolation of M. bovis in all of the animals, raccoons seem relatively resistant to oral M. bovis infection. This fact, together with the low number of orally inoculated raccoons that were able to excrete M. bovis in nasal secretions or saliva in the experiment suggested that in nature where the most probable way of infection is orally, a widespread tuberculosis among raccoons is unlikely (Cross et al 2000;Palmer et al 2002).…”

T-Cell mRNA Expression in Response toMycobacterium bovisBCG Vaccination andMycobacterium bovisInfection of White-Tailed Deer

“…At necropsy, the following tissues or fluids were collected and processed for isolation of M. bovis and microscopic analysis as described previously (26): palatine tonsil, lung, liver, and the mandibular, parotid, medial retropharyngeal, tracheobronchial, mediastinal, hepatic, mesenteric, and prefemoral lymph nodes. Tissues were processed for isolation of M. bovis as previously described (27). Isolates of M. bovis were identified by colony morphology, growth, and biochemical characteristics as well as by PCR.…”

Vaccination of white-tailed deer (Odocoileus virginianus) with Mycobacterium bovis bacillus Calmette Guerín

“…At necropsy, the following tissues or fluids were collected and processed for isolation of M. bovis and microscopic analysis as described [16]; palatine tonsil, lung, liver, mandibular, parotid, medial retropharyngeal, tracheobronchial, mediastinal, hepatic, mesenteric and prefemoral lymph nodes. Tissues were processed for isolation of M. bovis as previously described [17]. Isolates of M. bovis were identified by colony morphology, growth, and biochemical characteristics as well as by PCR.…”