title: Pathology and Epidemiology of Ceruminous Gland Tumors among Endangered Santa Catalina Island Foxes (Urocyon littoralis catalinae) in the Channel Islands, USA.
abstract: In this study, we examined the prevalence, pathology, and epidemiology of tumors in free-ranging island foxes occurring on three islands in the California Channel Islands, USA. We found a remarkably high prevalence of ceruminous gland tumors in endangered foxes (Urocyon littoralis catalinae) occurring on Santa Catalina Island (SCA)--48.9% of the dead foxes examined from 2001-2008 had tumors in their ears, and tumors were found in 52.2% of randomly-selected mature (≥ 4 years) foxes captured in 2007-2008, representing one of the highest prevalences of tumors ever documented in a wildlife population. In contrast, no tumors were detected in foxes from San Nicolas Island or San Clemente Island, although ear mites (Otodectes cynotis), a predisposing factor for ceruminous gland tumors in dogs and cats, were highly prevalent on all three islands. On SCA, otitis externa secondary to ear mite infection was highly correlated with ceruminous gland hyperplasia (CGH), and tumors were significantly associated with the severity of CGH, ceruminous gland dysplasia, and age group (older foxes). We propose a conceptual model for the formation of ceruminous gland tumors in foxes on SCA that is based on persistent, ubiquitous infection with ear mites, and an innate, over exuberant inflammatory and hyperplastic response of SCA foxes to these mites. Foxes on SCA are now opportunistically treated with acaricides in an attempt to reduce mite infections and the morbidity and mortality associated with this highly prevalent tumor.
authors.affiliation: Institute for Wildlife Studies, Arcata, California, United States of America.|Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.
authors.forename: T Winston
authors.initials: TW
authors.lastname: Vickers
authors.affiliation: Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.|Wildlife Investigations Lab, California Department of Fish and Wildlife, Rancho Cordova, California, United States of America.
authors.forename: Deana L
authors.initials: DL
authors.lastname: Clifford
authors.affiliation: Institute for Wildlife Studies, Arcata, California, United States of America.
authors.forename: David K
authors.initials: DK
authors.lastname: Garcelon
authors.affiliation: Catalina Island Conservancy, Avalon, California, United States of America.
authors.forename: Julie L
authors.initials: JL
authors.lastname: King
authors.affiliation: Catalina Island Conservancy, Avalon, California, United States of America.
authors.forename: Calvin L
authors.initials: CL
authors.lastname: Duncan
authors.affiliation: Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.|Departments of Pathology and Medicine, University of California San Diego, San Diego, California, United States of America.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Gaffney
authors.affiliation: Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.|Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.
authors.forename: Walter M
authors.initials: WM
authors.lastname: Boyce
mesh_terms: D000818:Animals; D002140:California; D004428:Ear Neoplasms / Q000453:epidemiology*; D004431:Ear, External / Q000469:parasitology / Q000473:pathology; D056727:Endangered Species; D005589:Foxes / Q000469:parasitology / Q000502:physiology*; D006965:Hyperplasia / Q000453:epidemiology; D062312:Islands; D008925:Mites / Q000472:pathogenicity; D018358:Neuroendocrine Tumors / Q000453:epidemiology*