STUDIES ON CURRENT TREND OF IMPORTED MALARIA IN JAPAN

Abstract

Current epidemiologic and therapeutic aspects of imported malaria in Japan were examined from 1980 to 1995 by sending questionnaires every year to more than 1,500 major hospitals. Imported malaria gradually increased in number from 1980 and became more than 100 from 1990. The number of cases with falciparum malaria increased in number from around 1993 and became comparable to the number of vivax malaria. As the presumptive place of contraction, Africa has been increasingly important, especially for falciparum malaria. Recently the number of foreign cases, most often from India, has been becoming rather high, ranging 24 to 36% of the total cases. We found 7 fatal cases with falciparum malaria, all of whom seemed to be infected in Africa except for a Japanese female due to domestic transfusion malaria. Recrudescence and relapse were detected at significant rates, i.e., 2.2 to 9.5% and 5.4 to 17.2% of the cases with falciparum and vivax malaria analyzed, respectively. Concerning the antimalarial drugs available in Japan, mefloquine has been the drug of choice after the Research Group for Development of Chemotherapeutic Agents against Tropical Parasitic Diseases supported by the Japanese Ministry of Health and Welfare started its import for clinical trial. Further efforts are still needed to improve the diagnostic and therapeutic capacity against imported malaria in Japan.