malariae is patchily present over the same range as P. falciparum. Plasmodium ovale is found in tropical Africa, and occasionally in Asia and the western Pacific.
One of the remarkable features of human plasmodia is their biology, which allows these small yet genetically complex microbes to survive and exploit several different environments: the liver and blood cells of humans as well as the gut, vascular system, and salivary glands of mosquitoes. With the advent of molecular tools such as polymerase chain reaction (PCR), an understanding of the genetic diversity of plasmodial parasites (in particular P. falciparum) has emerged. It is now known that many infected patients from falciparum-endemic areas harbor parasites belonging to more than one genotype. Some carry as many as 10 genotypes detectable by currently available methods (Greenwood, 2002).