Channel Island foxes endemic to Santa Catalina Island (Urocyon littoralis catalinae) have an extremely high prevalence of ear canal tumors. Although the exact cause is yet unknown, infection with ear mites (Otodectes cynotis) has been linked to sustained ear infections, abnormal cell growth, and tumor development in mature foxes. To better understand these links amid the backdrop of minimal genetic diversity, we sequenced the host-associated microbiome using 16S ribosomal RNA amplicon sequencing. We first characterized microbial community composition across six body sites to establish a baseline of healthy microbiota in this subspecies of fox. We then compared microbial species richness, evenness, and abundance between healthy and mite-infected ear canals to identify changes associated with disease.
Results/Conclusions
We found that healthy foxes exhibited rich communities of diverse microbes, with numerous taxa in high abundance. In contrast, mite infection was associated with reduced species richness and evenness, with one taxon dominating the ear canal community: Staphylococcus pseudintermedius. This taxon is associated with chronic inflammation in numerous host species, thereby supporting the hypothesis that ear mite infection may disrupt microbial communities, sustain inflammation, and contribute to tumorigenesis in Santa Catalina Island foxes. These results highlight the utility of microbial sequencing techniques in molecular ecology, disease ecology, and wildlife conservation. As the emergence of antibiotic resistant strains remains a prominent concern, uncovering high relative abundance of S. pseudintermedius provides critical insights into the pathogenesis of this complex system, while also allowing for more targeted disease monitoring for long-term health and viability.