Temporal and Geographic Clustering of Polyomavirus-Associated Olfactory Tumors in 10 Free-Ranging Raccoons (Procyon lotor)

Abstract

Reports of primary nervous system tumors in wild raccoons are extremely rare. Olfactory tumors were diagnosed postmortem in 9 free-ranging raccoons from 4 contiguous counties in California and 1 raccoon from Oregon within a 26-month period between 2010 and 2012. We describe the geographic and temporal features of these 10 cases, including the laboratory diagnostic investigations and the neuropathologic, immunohistochemical, and ultrastructural characteristics of these tumors in the affected animals. All 9 raccoons from California were found within a localized geographic region of the San Francisco Bay Area (within a 44.13-km radius). The tight temporal and geographic clustering and consistent anatomic location in the olfactory system of tumor types not previously described in raccoons (malignant peripheral nerve sheath tumors and undifferentiated sarcomas) strongly suggest either a common cause or a precipitating factor leading to induction or potentiation of neuro-oncogenesis and so prompted an extensive diagnostic investigation to explore possible oncogenic infectious and/or toxic causes. By a consensus polymerase chain reaction strategy, a novel, recently reported polyomavirus called raccoon polyomavirus was identified in all 10 tumors but not in the normal brain tissue from the affected animals, suggesting that the virus might play a role in neurooncogenesis. In addition, expression of the viral protein T antigen was detected in all tumors containing the viral sequences. We discuss the potential role of raccoon polyomavirus as an oncogenic virus.

Ecological and Evolutionary Perspectives on Transmissible Viral Tumours in Wild Species

“…Polyomaviruses have a circular double-stranded DNA genome. The genomic structure of RacPyV includes genes that encode viral proteins, and its genome is organised into early and late regions (Giannitti et al, 2014;Lu et al, 2017).…”

Bovine polyomavirus-1 (Epsilonpolyomavirus bovis): An emerging fetal pathogen of cattle that causes renal lesions resembling polyomavirus-associated nephropathy of humans

“…For example, Human polyomavirus-5 (Merkel cell polyomavirus –MCPyV–, Alphapolyomavirus quintihominis ) causes Merkel cell (neuroendocrine) carcinoma of the skin [3], while Procyon lotor polyomavirus-1 (syn. Raccoon polyomavirus-1 –RacPyV-1–, Alphapolyomavirus procyonis ) has been associated with tumors of the olfactory tract and brain in raccoons [4,5,6].…”

Diffuse Large B-Cell Lymphoma (DLBCL) in an Aged Raccoon (Procyon lotor)

“…In raccoons (Procyon lotor), neoplasms are rarely documented but the occurrence of cancer in raccoon populations might be underestimated due to the difficulty in estimating morbidity and mortality rates related to spontaneous diseases in wildlife [3]. Recent reports of neoplasm in raccoons include descriptions of raccoon polyomavirus-associated brain tumors [4][5][6], and a few offers concerning epithelial neoplasms [7][8][9]. Regarding round cell tumors, there are only two other earlier cases of lymphosarcoma in raccoons, both of which lack immunophenotype characterization [10,11].…”