Failure of Mefloquine Chemoprophylaxis for Malaria in Mozambique.

Abstract

Mefloquine is recommended for malaria chemoprophylaxis in short-term travelers to subSaharan Africa by many national and international organizations.’,’ Although mefloquine is presently highly effective against Pfalriparum in this area, resistance to the drug may develop, as occurred in Thailand in recent years.’ Continued monitoring and detailed documentation of malaria in people who use mefloquine for prophylaxis is therefore essential. We describe a case of malaria caused by P&kiparcrm in one Italian soldier returning &om Mozambique. He was taking mefloquine chenioprophylaxis. A 20-year-old man was admitted to hospital on July 16,1993, with a 3-day history of fever, diarrhea, and epigastric pain. He had served in the Italian army in rural areas ofMozambique from March 3 to July 13,1993. He reported no complaints during the stay. To prevent malaria he had taken chloroquine 300 mg weekly, and proguanil 200 mg daily until June 17. Then, as preventive guidelines in the army changed, he started taking mefloquine 250 mg weekly. He reported that he had not missed any doses of mefloquine, the last one being taken on July 15. O n the day of admission to hospital, July 16, a peripheral blood smear showed trophozoites of Pfalcipanm, with an asexual parasite count of 7950 per cmm. The serum mefloquine level in blood obtained on the same day was 920 ng per mL (determined by high performance liquid chromatography, at the Department of Clinical Chemistry, Falu Central Hospital, Sweden). The parasite strain was isolated, and in vitro sensitivity to antimalarial drugs was assessed with the 3H-hypoxanthine semimi~rotest.~