"Malaria is a serious and sometimes fatal disease which is widespread in many tropical and subtropical countries. It is caught by being bitten by an infected mosquito that is carrying the malaria parasites in its saliva.
The malaria parasite is a microscopic organism called a Plasmodium and it belongs to the group of tiny organisms known as protozoans. There are four types of plasmodium: P. falciparum (the most dangerous), P. vivax, P. ovale and P. malariae. The species of mosquito that carries the malaria parasites is the Anopheles mosquito.
These parasites enter the host's bloodstream when bitten by an infected mosquito and then migrate to the liver where they multiply before returning back into the bloodstream to invade the red blood cells.
The parasites continue to multiply inside the red cells until they burst releasing large numbers of free parasites into the blood plasma causing the characteristic fever associated with the disease. This phase of the disease occurs in cycles of approximately 48 hours.
Malaria occurs in over 100 countries and more than 40% of the people in the world are at risk. Large areas of Central and South America, Hispaniola (Haiti and the Dominican Republic), Africa, the Middle East, the Indian subcontinent, Southeast Asia, and Oceania are considered malaria-risk areas."