Blood Parasites Principal Causative Organisms of Tropical Diseases
The causative Plasmodium organisms are transmitted to man as sporozoites in the saliva of the feeding anopheles mosquito. The organisms travel in the bloodstream from the capillaries to the liver, where they undergo further development. They enter the liver cells (primary tissue forms) in the “pre-erythrocytic phase” of their life cycle, and after a variable period they are released into the peripheral blood as merozoites. There they invade the erythrocytes, inciting a paroxysm of fever. Inside the red cells the plasmodia (merozoites) mature through several stages, culminating in the discharge of merozoites from the remains of the erythrocyte; these then proceed to infect fresh erythrocytes. This process takes about 48 h for the parasite of tertian malaria (Plasmodium vivax and Plasmodium ovale) and malignant tertian malaria (Plasmodium falciparum) and 72 h for the parasite of quartan malaria (Plasmodium malariae).
KeywordsVisceral Leishmaniasis Ring Form Cutaneous Leishmaniasis Parasite Burden Blood Parasite
Unable to display preview. Download preview PDF.