Prevalence of Lesional and Nonlesional Dermatophytosis in Shelter/Rescue Guinea Pigs (Cavia porcellus) in Southern California, USA.

Active dermatophytosis is uncommon in shelter guinea pigs; positive PCR results require careful clinical correlation before diagnosis.

This prospective observational study assessed the prevalence of dermatophytosis in 85 shelter and rescue guinea pigs (Cavia porcellus) across five Southern California locations, using six diagnostic modalities: acetate tape preparation, superficial-to-deep skin scraping, trichogram, fungal culture, PCR, and next-generation sequencing (NGS). Active dermatophyte infection confirmed by fungal culture was rare, with only one animal (1.18%) culturing positive for Trichophyton benhamiae, which was also confirmed by PCR and NGS. In contrast, PCR detected dermatophyte DNA in 63.5% of animals, and NGS in 7.06%, suggesting widespread environmental exposure or subclinical carriage rather than true active infection in most cases. Notably, no animals had abnormal trichogram findings, and only three of 56 PCR/NGS-positive animals (5.36%) exhibited skin lesions consistent with dermatophytosis. Conversely, six animals had compatible clinical lesions but tested negative on all assays. Two animals (2.35%) were found to harbor the louse Gliricola porcelli. The study highlights poor inter-test agreement among diagnostic modalities, underscoring that positive molecular results must be interpreted cautiously within the clinical context. Given the zoonotic potential of dermatophytosis—particularly T. benhamiae—these findings have important implications for pre-adoption screening protocols and client education. Clinicians should rely on a combination of clinical signs, culture, and molecular testing rather than any single modality when evaluating guinea pigs for suspected dermatophytosis.

This summary was distilled by AI and may occasionally misinterpret data. Confirm critical details with the primary literature before clinical application.