Scopulariopsis brevicaulis fungal outbreak in laboratory rats

Abstract

This study describes an outbreak of alopecia in laboratory rats caused by the saprophytic fungi Scopulariopsis brevicaulis in a Brazilian lab animal facility. Initially, lesions were identified only in females during the lactation period, which showed circumscribed areas with alopecia without pruritus extensively at the abdomen and the medial side of the thighs. Later during the course of the infection, skin lesions affected both genders reaching about 10% of the colony. Skin scrapings, hair, and environmental samples from the facility were sent for analysis. The cultures were carried out in Sabouraud agar and over seven days fast-growing colonies varying in color from white to brown were observed. Micromorphology showed mycelium and characteristic ringworms of the fungus S. brevicaulis . There is a similar report of an outbreak of this fungus in Turkey. To date, this is the first report in the literature of the fungus S. brevicaulis causing disease in laboratory rats in Brazil. Environmental contamination with S. brevicaulis was observed in the dirty and breeding rooms of the facility. All animals that presented lesions had positive cultures for S. brevicaulis . The presence of S. brevicaulis was also observed in animals without any clinical sign which indicates the possibility of positive carriers in their coat. Similarly, one study reported that the S. brevicaulis was found in 36 animals out of 79 asymptomatic animals analyzed 22 .