Topical N,N-Diethyl-m-toluamide (DEET) was studied as a schistosomiasis prophylactic
in vivo for the use of individuals with limited exposure. Fifteen subjects, on a
3-week expedition to Lake Malawi in September 2001, applied 50% DEET to their skin
after exposure to lake water. No subjects developed evidence of a new infection
at 3-month follow-up.