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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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Map of the Channel Islands (California, USA).Distribution of foxes that are uninfected or infected with ear mites, and foxes that have ceruminous gland tumors. Island foxes do not reside on Santa Barbara or Anacapa islands.
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pone.0143211.g001: Map of the Channel Islands (California, USA).Distribution of foxes that are uninfected or infected with ear mites, and foxes that have ceruminous gland tumors. Island foxes do not reside on Santa Barbara or Anacapa islands.

Mentions: Six subspecies of island fox (Urocyon littoralis), diminutive descendants of the mainland gray fox (U. cinereoargenteus), are found on the Channel Islands located off the mainland coast of southern California, USA [1] (Fig 1). Northern island subspecies include the San Miguel Island (SMI) Fox (U. l. littoralis), Santa Rosa Island (SRI) Fox (U. l. santarosae), and Santa Cruz Island (SCZ) Fox (U. l. santacruzae), and southern island subspecies include Santa Catalina Island (SCA) Fox (U. l. catalinae), San Nicolas Island (SNI) Fox (U. l. dickey), and San Clemente Island (SCI) Fox (U. l. clementae). Predation, disease, and other factors led to catastrophic declines in fox numbers to < 1,500 for all six subspecies combined in 2002 [1,2], and all northern island subspecies (SMI, SRI, SCZ), and one southern island subspecies (SCA), were listed as endangered in 2004 [3]. Population recovery of all 4 federally endangered subspecies is occurring, but no subspecies have been delisted or down-listed to date [1].


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)

Map of the Channel Islands (California, USA).Distribution of foxes that are uninfected or infected with ear mites, and foxes that have ceruminous gland tumors. Island foxes do not reside on Santa Barbara or Anacapa islands.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0143211.g001: Map of the Channel Islands (California, USA).Distribution of foxes that are uninfected or infected with ear mites, and foxes that have ceruminous gland tumors. Island foxes do not reside on Santa Barbara or Anacapa islands.
Mentions: Six subspecies of island fox (Urocyon littoralis), diminutive descendants of the mainland gray fox (U. cinereoargenteus), are found on the Channel Islands located off the mainland coast of southern California, USA [1] (Fig 1). Northern island subspecies include the San Miguel Island (SMI) Fox (U. l. littoralis), Santa Rosa Island (SRI) Fox (U. l. santarosae), and Santa Cruz Island (SCZ) Fox (U. l. santacruzae), and southern island subspecies include Santa Catalina Island (SCA) Fox (U. l. catalinae), San Nicolas Island (SNI) Fox (U. l. dickey), and San Clemente Island (SCI) Fox (U. l. clementae). Predation, disease, and other factors led to catastrophic declines in fox numbers to < 1,500 for all six subspecies combined in 2002 [1,2], and all northern island subspecies (SMI, SRI, SCZ), and one southern island subspecies (SCA), were listed as endangered in 2004 [3]. Population recovery of all 4 federally endangered subspecies is occurring, but no subspecies have been delisted or down-listed to date [1].

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