Maleria

What Is Malaria?

Malaria is caused by single-celled protozoan parasites of the genus Plasmodium. Four species infect humans by entering the bloodstream: Plasmodium falciparum, which is the main cause of severe clinical malaria and death; Plasmodium vivax; Plasmodium ovale; and Plasmodium malariae. Inoculation of parasite sporozoites occurs via the bite of infected blood-feeding female mosquitoes of the genus Anopheles. In humans, the parasites multiply exponentially in the liver, releasing merozoites that develop and multiply in infected red blood cells. With a blood meal, mosquitoes ingest Plasmodium gametocytes, which undergo another reproductive phase inside the mosquito before being transferred to another human host.

Current global status. Malaria is responsible for 273 million clinical cases and 1.12 million deaths annually. More than 40% of the global population are estimated to be at risk.

Distribution. Malaria occurs in 100 countries, but is mainly confined to poor, tropical areas of Africa, Asia and Latin America. More than 90% of malaria cases occur in tropical Africa, particularly among young children and pregnant women.

Causes of Malaria

The cause of malaria is an infection with a parasite. Plasmodium is the name for the species of microscopic parasites that cause the disease (see Malaria Causes). There are over 100 species of Plasmodium, which can infect animal species, such as:

• Reptiles

• Birds

• Various mammals.

Only four species of Plasmodium infect humans in nature. These four types include:

• Plasmodium falciparum

• Plasmodium vivax

• Plasmodium ovale

• Plasmodium malariae.

How Is It Transmitted?

Malaria is usually transmitted through the bite of an infected female Anopheles mosquito. Less commonly, the disease is spread through contact with infected blood.

Malaria is not transmitted from person to person, like the common cold or the flu. You cannot get the disease from casual contact with infected...