Taking the body temperature of a Thai patient suffering from malaria due to Plasmodium vivax. Malaria is the most important of all the parasitic diseases which affect humans, bringing suffering to around 200 million people each year & death to over a million of these. Of over a hundred species of the malarial parasiste (Plasmodium), only four choose humans as their natural host. They are P. falciparum, P. malariae, P. vivax & P. ovale. Although each species provokes different biological & clinical characteristics, the parasites' life cycles are similar, in both their mosquito (Anopheles sp.) & human hosts.