Preventive therapy for malaria.

The incidence of malaria in travelers returning to the United States has been increasing. Persons visiting areas where malaria is endemic should use insect repellent, wear clothing that covers the arms and legs, and remain in screened areas between dusk and dawn. Chemoprophylaxis for travelers consists of weekly doses of chloroquine; a new drug, mefloquine, should be used in the increasing number of countries where chloroquine-resistant malaria is found. Travelers to these areas should carry three tablets of pyrimethamine-sulfadoxine, which should be taken for presumptive treatment of malaria at the onset of chills and fever. It is essential that chemoprophylaxis be continued for four to five weeks after departure from endemic areas. In travelers who develop symptoms of malaria after returning from an endemic area, it is imperative that treatment be started even if blood smears are negative.