CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOBackground A 40-year-old female laboratory technician accidentally came into contact with water that contained snails shedding Schistosoma mansoni cercariae while she was maintaining an aquarium. Several minutes after exposure to the contaminated water, she experienced severe itching in the area of exposure, and several papules were observed. Investigations Taking of medical history to provide evidence of accidental contact with water contaminated with S. mansoni cercariae; physical examination; and stool examinations by the Kato-Katz, formol-ether concentration and sedimentation methods carried out four times weekly, starting 45 days after infection and continuing until 10 weeks after infection. Diagnosis S. mansoni infection. Management A single oral dose of 50 mg/kg oxamniquine on the day of the incident