Dermatophytosis due to Trichophyton Verrucosum in a Six-Month-Old Male Sokoto Red Goat from Dogarawa, Zaria, Nigeria

Abstract

Dermatophytosis, despite its global economic importance, has generally been under reported particularly among small ruminants in northern Nigeria. This paper describes the isolation of Trichophyton verrucosum from a Sokoto Red goat in Dogarawa, Zaria. A 6-month-old male goat was presented with skin lesions suggestive of dermatophytosis. Skin scrapings including hair pullouts were collected and processed for direct examination and culture. Direct examination was performed by digesting a portion of the sample in a drop of 10% potassium hydroxide on a clean glass slide, covered with a cover slip and examined under a light microscope, using the x40 objective lens. The remaining part of the sample was inoculated onto two plates, each containing Sabouraud’s dextrose agar incorporated with chloramphenicol at the rate of 16µg/ml and cycloheximide at 0.5mg/ml. One of the plates was incubated at room temperature for 21 days while the second plate was incubated at 37ºC for the same period. A portion of mycelium from each of the plates was stained with lactophenol cotton blue and examined with a light microscope. Direct microscopic examination of the sample showed hyaline septate hyphae in skin scales while chains of large ectothrix spores were seen in hair indicating dermatophyte infection. Microscopic examination of the isolate incubated at room temperature revealed sterile mycelium with broad, irregular hyphae, bearing a single, large microconidium while the isolate incubated at 37ºC showed numerous chlamydospores occurring in chains referred to as “chains of pearls” typical of T. verrucosum.  The ability to grow optimally at 37ºC and forming long chains of chlamydoconidia is peculiar to T. verrucosum and therefore, diagnostic for this dematophyte. It was concluded that T. verrucosum was the cause of ringworm in a 6-month-old goat.