The collaborative anti-schistosome drug testing program between the University of Brasilia and the U.S. Army Medical Research Unit WRAIR Brasilia continues to screen new chemical compounds for prophylactic and therapeutic activity against schistosomiasis. The U.S. Armys Anti-schistosome Drug Development Program, Walter Reed Army Institute of Research, provides selected drugs for prophylactic and curative testing in mice infected with schistosomiasis mansoni. The drugs are tested initially for prophylactic activity by the mortality test system which uses mice exposed to 3,000 or more S. mansoni cercariae. The laboratory Biomphalaria glabrata snail colony supported a daily inventory of 1,318 S. mansoni snails shedding cercariae. The weekly cercarial collections of five million were more than adequate to infect prophylactic test group mice with 3,000 or more cercariae.