Leptospirosis and Tularaemia in Raccoons (Procyon lotor) of Larimer Country, Colorado

Abstract

Raccoons (Procyon lotor) are commonly implicated as carriers of many zoonotic pathogens. The purpose of this cross-sectional study was to look for Leptospira interrogans and Francisella tularensis in opportunistically sampled, free-ranging raccoons of Larimer Country, Colorado, USA. Sixty-five animals were included in the study and testing consisted of gross post-mortem examination, histopathology, and both immunohistochemistry and PCR for L. interrogans and F. tularensis. No significant gross lesions were identified and the most common histological lesions were lymphoplasmacytic interstitial nephritis and pulmonary silicosis; rare periportal hepatitis, splenic lymphoid hyperplasia and small pulmonary granulomas were also identified. Of 65 animals, 20 (30%) were positive for Leptospira on IHC but only one by PCR. Animals with inflammation in their kidneys were seven times more likely to be positive for Leptospira than animals without inflammation. The severity of inflammation was variable but often mild with minimal associated renal pathology. One animal was positive for Francisella on both IHC and PCR; IHC staining was localized to histiocytic cells within a pulmonary granuloma. In Colorado the significance and epidemiology of Leptospira is poorly understood. The high prevalence of infection in raccoons in this study population suggests that this species may be important in the regional epidemiology or could be used to estimate risk to domestic animals and humans. Identification of a single Francisella positive animal is significant as this is an uncommon disease in terrestrial animals within the state; the apparently higher prevalence in this peridomestic species implies that raccoons may be good indicators of the pathogen in the region. The results of this study suggest that raccoons may serve as effective sentinels for both Leptospira and Francisella in the state of Colorado. Further studies are needed to better characterize the prevalence and epidemiology of both organisms within the region.

Serologic and Urinary PCR Survey of Leptospirosis in Healthy Cats and in Cats with Kidney Disease

“…In addition, wild animals, including raccoons and skunks, were identified as risk factors in PCR‐positive cats ( P ≤ .03). The former are also known maintenance hosts of the serovars Pomona and Bratislava and might indirectly infect cats . In fact, the population of raccoons in Quebec is massive, particularly in the Montérégie region where most of the cats were recruited, and raccoons are known carriers of Pomona and Bratislava .…”

Leptospira and Leptospirosis

“…De Faria et al (2008) reported that up to 80.3% of Norway rats (Rattus norvegicus), a species that spread almost all over the globe, were culture positive and 68.1% were shown positive by antibody titers of at least 1:100 in a microscopic agglutination test (MAT). Other species of wild mammals have been detected as leptospiral carriers (Andreoli et al, 2014, Duncan et al, 2012, Pinna et al, 2012, Scialfa et al, 2013. In France, seropositivity rates were found to range from 31% in farmed American mink, 74% in wild European mink and up to 89% in stone martens (Moinet et al, 2010).…”

Procyonidae, Viverridae, Hyenidae, Herpestidae, Eupleridae, and Prionodontidae

“…Several serologic surveys in the United States demonstrate that raccoons commonly have circulating antibodies to a number of L. interrogans serovars including grippotyphosa, autumnalis, hardjo, and icterohemorrhagiae (Junge et al, 2007;Raizman et al, 2009;Richardson and Gauthier, 2003). Some studies have confirmed nephritis in association with the bacteria by using PCR and immunohistochemistry, indicating that raccoons are susceptible to disease and do not simply serve as asymptomatic reservoirs (Duncan et al, 2012;Hamir et al, 2001;Koizumi et al, 2009). Leptospiral infections have also been reported in mongoose and genets, with L. interrogans serovar icterohemorrhagiae being the most commonly identified strain (Millán et al, 2009;Moinet et al, 2010).…”