Pathology of neurologic disorders of raccoons (Procyon lotor)

Abstract

The raccoon (Procyon lotor) is almost ubiquitous in North America. In recent times, it was introduced in many parts of the world where it has now become largely feral. Since the outbreak of raccoon rabies epizootic in eastern United States and Canada, most diagnostic laboratories have had increased numbers of raccoon carcasses or raccoon brain submissions for diagnosis of rabies. However, since a number of other diseases that affect the central nervous system and have similar clinical signs as rabies have been documented in this species, the current review attempts to bring together the published information on neurologic disorders of raccoons.

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

“…12.10). Seroprevalence of exposure to Toxoplasma gondii is relatively high in free-ranging raccoons and lower ringtails in North America, with seropositivity rates of ∼80% and ∼20%, respectively, depending on the geographical location (Hamir, 2011a;Suzán and Ceballos, 2005). The pyogranulomatous pneumonia seen in raccoons with CDV and Toxoplasma coinfections are similar to those described in other species.…”

“…It appears multifocally as round deposits of deeply basophilic, refractile material arranged in concentric rings in the walls of small capillaries and randomly throughout the neuropil. While these mineralized foci are sometimes associated with mild inflammation and fibrosis, the lack of associated clinical signs and lack of disruption of surrounding tissue make these foci of mineralization an incidental finding (Hamir, 2011a). Another commonly encountered lesion in the CNS of raccoons is neuroaxonal degeneration, which is seen consistently in the gracilis and cuneate nuclei of the medulla and is characterized by abundant vacuolated neurons and axonal spheroids.…”

“…There are no gross lesions directly associated with rabies virus infection, though affected animals may have superficial cutaneous lesions (i.e., contusions), tooth fractures or gastric foreign bodies as a result of ataxia, incoordination, aggression, and pica. Histopathologic findings include polioencephalomyelitis with perivascular cuffing by lymphocytes and plasma cells throughout cerebrum, brainstem, and spinal cord (Hamir, 2011a;Hamir et al, 1998;Ruprecht et al, 2001). In some cases, intracytoplasmic inclusion bodies (Negri bodies) can be seen ( Fig.…”

“…Inclusions are reported to be most common in the hippocampus of carnivores but they may also be abundant in other regions including but probably not limited to cortical neurons, basal nuclei, thalamus, and caudal colliculi (De Araujo et al, 2014). The gold standard for diagnosis of rabies virus infection (in any species) is direct staining with fluorescent antibody (Davidson, 2006;Hamir, 2011a;Ruprecht et al, 2001). Domestic dogs and other nondomestic canid and carnivore species can serve as reservoirs for rabies virus in different geographic locations; mongoose are recognized reservoirs in Puerto Rico (Berentsen et al, 2015;Sabeta et al, 2008;Wicker et al, 2017).…”

Novel Polyomavirus associated with Brain Tumors in Free-Ranging Raccoons, Western United States

“…Most veterinary diagnostic laboratories receive large numbers of raccoon ( Procyon lotor ) carcasses for diagnosis, yet tumors of any type are rarely reported ( 15 – 17 ). In northern California and southern Oregon, we diagnosed 10 cases of olfactory tract/frontal lobe brain tumors in free-ranging raccoons during March 2010–May 2012.…”