Molecular Diagnosis as an Alternative Method for Dermatophytes Identification in Cattle Herds

Abstract

Dermatophytes are filamentous fungi that cause infections in keratinised animal tissues as well as human including hair, skin, and nails. Dermatophytosis or ringworm is a highly contagious disease caused by fungi by fungi from three genera: Trichophyton, Epidermophyton (Deuteromycetes) and Microsporum. Its zoonotic potential causes economic losses in cattle farms. This study assessed the prevalence of calves' dermatophytosis in north-western of Iraq using PCR technique compared with traditional method. Fifty affected calves were used in this study during the period from September 2019 to March 2020. The affected calves were distributed in seven herds from different areas in Nineveh province /Mosul-Iraq. Skin scraping and hair samples were collected from these affected calves. The samples were mixed with 10-15% KOH and cultured on Sabouraud dextrose agar with gentamicin and chloramphenicol. The isolates of dermatophytes were identified based on their colony morphology while morphological characterization was done using direct microscopy. Fungal isolates were confirmed by internal transcribed spacer (ITS)-PCR method. Thirteen  isolates of the genus Microsporium spp. (Microsporium canis) with a percentage of 26% and one isolate of the genus Epidermophyton spp. (Epidermophyton  floccosum) with a percentage of 2% was detected. PCR method offers stellar performance in all tested samples. In fact detection of dermatophytes were increased the species-specific based on PCR technique compared with culture. We concluded from this study that applying ITS-PCR technique confirmed as a reliable method for the identification of dermatophytes because it is a rapid and sensitive diagnostic assay for dermatophytosis compared to the conventional methods.