Ninety percent of the world's malaria cases occur in Africa. Chloroquine resistance is widespread in Africa. Now, malaria outbreaks are being reported in some locations of Africa that had been previously thought to be at elevations too high for malaria transmission, such as the highlands of Kenya. Some scientists hypothesize this is due to climatic change, while others hypothesize that this is due to human migration. Also, malaria has resurged in certain locations of Africa that had previously had effective control programs, such as Madagascar, South Africa, and Zanzibar.
Malaria also occurs in portions of Iran and the Middle East.
Plasmodium falciparum is common, as is Plasmodium vivax . Plasmodium falciparum infections unfortunately increased during the 1990s in India and Sri Lanka. Resistance in Plasmodium falciparum to multiple drugs is present in portions of Cambodia, Myanmar, Thailand, and Laos, and chloroquine resistance is widespread in Asia. Plasmodium malariae also occurs in this area. The most common species in this area is Plasmodium vivax , although there is an unfortunate increase in Plasmodium falciparum cases, particularly in regions where control programs have deteriorated or been abandoned since the early 1990s.