Collecting blood by using finger-stick for malaria laboratory diagnostic test. Fundação de Medicina Tropical do Amazonas ( Amazonas Tropical Medicine Foundation ), Manaus city, Brazil. Malaria is a mosquito-borne infectious disease of humans caused by eukaryotic protists of the genus Plasmodium. It is widespread in tropical and subtropical regions. The disease results from the multiplication of malaria parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases progressing to coma, and death.