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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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Scattergram developed from canonical discriminant analysis of 9 morphometric characters measured on Otodectes cyanotis mites from different hosts illustrating morphologic differentiation of mites present in island foxes from Santa Catalina (SCA), San Clemente (SCI) and San Nicolas Islands (SNI) and feral cats from SCA and the mainland.Discriminant functions 1 (DF1; body length and outer opisthosomal setae #3 length) and 2 (DF2; outer opisthosomal setae #3 length) cumulatively accounted for 87% of the variation in group measurement means observed.
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pone.0143211.g008: Scattergram developed from canonical discriminant analysis of 9 morphometric characters measured on Otodectes cyanotis mites from different hosts illustrating morphologic differentiation of mites present in island foxes from Santa Catalina (SCA), San Clemente (SCI) and San Nicolas Islands (SNI) and feral cats from SCA and the mainland.Discriminant functions 1 (DF1; body length and outer opisthosomal setae #3 length) and 2 (DF2; outer opisthosomal setae #3 length) cumulatively accounted for 87% of the variation in group measurement means observed.

Mentions: The prevalence of ear mites was very high on all three islands—98.7% on SCA, and 100% on both SCI and SNI, and there was no difference in the intensity of infection (mite scores) among infected foxes on each island. Morphometric analyses provided evidence of phenotypic differentiation among mites from foxes on the three islands (Fig 8). Wilk’s lambda was significant for all four canonical discriminant functions, but the first two discriminant functions (DF1 and DF2) cumulatively accounted for 87% of the variation in the group measurement means observed. Based on standardized correlation coefficients, body length and outer opisthosomal setae #3 length were the most important morphologic characters to describe DF1 and outer opisthosomal setae #3 length was the most important morphologic character to describe DF2. Mites were most similar from foxes on the two islands closest to each other (SCA and SCI, Fig 1), while those from SNI clustered more distantly. Somewhat surprisingly, mites from cats on SCA and mainland California formed distinct clusters from each other and from all of the fox mites.


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)

Scattergram developed from canonical discriminant analysis of 9 morphometric characters measured on Otodectes cyanotis mites from different hosts illustrating morphologic differentiation of mites present in island foxes from Santa Catalina (SCA), San Clemente (SCI) and San Nicolas Islands (SNI) and feral cats from SCA and the mainland.Discriminant functions 1 (DF1; body length and outer opisthosomal setae #3 length) and 2 (DF2; outer opisthosomal setae #3 length) cumulatively accounted for 87% of the variation in group measurement means observed.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0143211.g008: Scattergram developed from canonical discriminant analysis of 9 morphometric characters measured on Otodectes cyanotis mites from different hosts illustrating morphologic differentiation of mites present in island foxes from Santa Catalina (SCA), San Clemente (SCI) and San Nicolas Islands (SNI) and feral cats from SCA and the mainland.Discriminant functions 1 (DF1; body length and outer opisthosomal setae #3 length) and 2 (DF2; outer opisthosomal setae #3 length) cumulatively accounted for 87% of the variation in group measurement means observed.
Mentions: The prevalence of ear mites was very high on all three islands—98.7% on SCA, and 100% on both SCI and SNI, and there was no difference in the intensity of infection (mite scores) among infected foxes on each island. Morphometric analyses provided evidence of phenotypic differentiation among mites from foxes on the three islands (Fig 8). Wilk’s lambda was significant for all four canonical discriminant functions, but the first two discriminant functions (DF1 and DF2) cumulatively accounted for 87% of the variation in the group measurement means observed. Based on standardized correlation coefficients, body length and outer opisthosomal setae #3 length were the most important morphologic characters to describe DF1 and outer opisthosomal setae #3 length was the most important morphologic character to describe DF2. Mites were most similar from foxes on the two islands closest to each other (SCA and SCI, Fig 1), while those from SNI clustered more distantly. Somewhat surprisingly, mites from cats on SCA and mainland California formed distinct clusters from each other and from all of the fox mites.

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