"Plasmodium vivax" is found mainly in Asia, Latin America, and in some parts of Africa. "P. vivax" is believed to have originated in Asia, but recent studies have shown that wild chimpanzees and gorillas throughout central Africa are endemically infected with parasites that are closely related to human "P. vivax." These findings indicate that human P. vivax is of African origin. "Plasmodium vivax" accounts for 65% of malaria cases in Asia and South America. Unlike "Plasmodium falciparum", "Plasmodium vivax" is capable of undergoing sporogonic development in the mosquito at lower temperatures. It has been estimated that 2.5 billion people are at risk of infection with this organism.