The purpose of this proposed project is to collect ectoparasites (ear mites) and biopsy tissue from the ears of island foxes (Urocyon littoralis) on Santa Catalina Island in an attempt to better understand the epidemiology of ear cancers found in the foxes. This is part of a larger study that will also involve collection of the same tissues on two of the other Channel Islands (San Clemente and Santa Catalina) for a comparative analysis of the three fox populations.

IWS biologists first discovered the ear tumors in island foxes in 2001 and in conjunction with our colleagues at the University of California-Davis (Dr. Linda Munson and Dr. Brian Stacy) the tumors were identified as a rare form of cancer known as ceruminous gland carcinoma. Based on experiences with captive husbandry of foxes that have been diagnosed with this cancer, it appears to have a rapidly progressing condition that eventually contributed to the death of most affected animals. Most cancers were confined to the ear canal, but others had extensive local invasion and metastasis. Biopsy of foxes captured during 2005 road-transect trapping on Santa Catalina Island estimated the prevalence in foxes over 3 yrs old to be approximately 38%. Of 66 foxes with proliferative ear canal lesions, 65% had ceruminous gland tumors.

Our research goals are to 1) determine the prevalence of ceruminous gland cancer in island foxes and 2) determine if one or more of the following factors is a risk for cancer: severity of otitis, severity of ceruminous gland hyperplasia, ear mite species, ear mite antigenicity, presence and type of bacterial, yeast, or fungal infection, papilloma or herpes virus infection, polychlorinated biphenyls or organo-chlorine exposure, age class, sex, or island.