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Pathology and Epidemiology of Ceruminous Gland Tumors among Endangered Santa Catalina Island Foxes (Urocyon littoralis catalinae) in the Channel Islands, USA.

Vickers TW, Clifford DL, Garcelon DK, King JL, Duncan CL, Gaffney PM, Boyce WM - PLoS ONE (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Institute for Wildlife Studies, Arcata, California, United States of America.

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.

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Photo of ceruminous gland tumor after local invasion into adjacent bulla tympanica, pharynx, temporal, and occipital bones and skull of a Santa Catalina Island fox.
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pone.0143211.g003: Photo of ceruminous gland tumor after local invasion into adjacent bulla tympanica, pharynx, temporal, and occipital bones and skull of a Santa Catalina Island fox.

Mentions: On gross examination, ceruminous gland tumors varied in size, shape, and invasiveness. Adenomas were often discrete, raised, round masses with a smooth surface. Carcinomas had irregular borders and could be exophytic and pedunculated with an ulcerated surface. Some tumors occluded the entire ear canal and extended beyond the external pinna (Fig 2). Less frequently, carcinomas were locally invasive, infiltrating adjacent bone and in one case extending into the skull (Fig 3), or exhibiting metastasis to regional lymph nodes and lung (Fig 4).


Pathology and Epidemiology of Ceruminous Gland Tumors among Endangered Santa Catalina Island Foxes (Urocyon littoralis catalinae) in the Channel Islands, USA.

Vickers TW, Clifford DL, Garcelon DK, King JL, Duncan CL, Gaffney PM, Boyce WM - PLoS ONE (2015)

Photo of ceruminous gland tumor after local invasion into adjacent bulla tympanica, pharynx, temporal, and occipital bones and skull of a Santa Catalina Island fox.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664485&req=5

pone.0143211.g003: Photo of ceruminous gland tumor after local invasion into adjacent bulla tympanica, pharynx, temporal, and occipital bones and skull of a Santa Catalina Island fox.
Mentions: On gross examination, ceruminous gland tumors varied in size, shape, and invasiveness. Adenomas were often discrete, raised, round masses with a smooth surface. Carcinomas had irregular borders and could be exophytic and pedunculated with an ulcerated surface. Some tumors occluded the entire ear canal and extended beyond the external pinna (Fig 2). Less frequently, carcinomas were locally invasive, infiltrating adjacent bone and in one case extending into the skull (Fig 3), or exhibiting metastasis to regional lymph nodes and lung (Fig 4).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Institute for Wildlife Studies, Arcata, California, United States of America.

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.

Show MeSH
Related in: MedlinePlus