Malaria is a disease caused by unicellular parasites that long ago gave up an independent photosynthetic lifestyle in exchange for a parasitic existence inside terrestrial vertebrates and mosquitoes. The precise evolutionary steps taken more than 100 million years ago to achieve this remarkable transition from innocuous red alga to insidious parasite of two biologically disparate classes of host are probably unknowable, but the end result has been disease of varying severity for millions of mammals, birds and reptiles, including, in all probability, dinosaurs.

This content is only available as a PDF.