[Studies on current trend of imported malaria in Japan--pediatric cases in recent 20 years]

Imported malaria has been increasing according to the recent globalization of Japan. There are about 120 clinical cases of malaria which include a few pediatric cases (approximately 1%) every year. Generally, pediatric cases often have an atypical onset and course compared to adult cases, and also develop serious and fatal effects in a short time. In this study, we examined imported malaria cases in subjects under 15 years old from 1980 to 1999 conducted by Research group on clinical evaluation against orphan drugs in the treatment of imported tropical diseases and parasitic diseases. During the 20 years we found 44 clinical cases in children. Of these 70% were foreign cases. Among the species of parasites, there were 21 cases of Vivax malaria and 17 cases of Falciparum malaria and a few cases of Malariae and Ovale malaria were also found, which is rare even in adults. Concerning the drugs chosen in Japan for chemotherapy to treat malaria, chloroquine and primaquine seemed to be employed most frequently before 1990, however mefloquine or artesunate seemed to be more common after 1990. Also, most pediatric cases were former residents or refugees from tropical countries, however some cases were in Japanese children who had recently visited those areas with their families. There have been no fatalities in pediatric cases of malaria, however tropical diseases, including malaria, must be rule out, when examining pyretic children, considering the number of travelers going abroad has been increasing.