The document discusses the life cycle and transmission of malaria parasites. It notes that malaria is caused by four species of Plasmodium, which have different geographic distributions and cause different percentages of infections in India. It also describes the life history of the malaria parasite, including that it requires human and mosquito hosts to spread, and identifies some conditions necessary for humans to serve as reservoirs of the parasite. It lists several factors that can influence the geographic distribution and transmission of malaria, including environmental, socioeconomic, and human factors.