Catalina Island foxes suffered a catastrophic decline following the introduction of Canine Distemper Virus in the late 1990s. As their population began to recover a new challenge threatened their survival: cancer. Fatal cancerous tumors, which developed in the ear canal, were discovered in a high percentage of the small surviving Catalina population.
FIF first reported on this threat in 2006 and 2007 (mysterious cancer). A new research paper details that between 2001 and 2008 nearly half of all adult Catalina Island foxes were found to have nodule-like tumors present in their ear canals and approximately two-thirds of these tumors were cancerous.
In the search to unravel the cause, it was discovered that nearly all island foxes with the tumors were also infected with ear mites. Veterinarians from UC Davis and biologists with the Catalina Island Conservancy and the Institute for Wildlife Studies hypothesized that treating the ear mites might reduce the irritation in infested foxes and therefore reduce inflammation. If the ear mites could be controlled or eliminated perhaps the progression to disease could be reduced.
|Catalina Island fox receiving health check|
|photo courtesy of M. Baffa|
Breaking the cycle of ear mite infestation, irritation, cancer, and transmission to other foxes is good news for Catalina Island foxes. It is also an example of the interconnection between various island fox conservation efforts. Annual monitoring and health checks, ID microchips, various conservation entities working together, these are all pieces of successful island fox recovery.
Why this subspecies of island fox is prone to cancerous ear tumors when foxes on other islands are not, remains unknown. Further research and genetic studies may offer new insight.
Read the Full Papers:
Prevalence of the disease:
Controlling the disease risk factors: