More about malaria

Plasmodia – the cause of malaria

Malaria is caused by parasites of the genus Plasmodium, single-celled organisms that are widespread in the animal kingdom. Plasmodia are blood parasites that use mosquitoes as a vector to infect a host (such as reptiles, birds, and mammals - including man). In human malaria, the vector is the Anopheles mosquito. These mosquitoes live in close association with man, and in many regions of the world, population densities of both vector and host are large. This means that the parasites can spread easily, resulting in an extremely high risk of acquiring malaria.

Human malaria is caused by four species of plasmodia parasites:

• Plasmodium falciparum
• P. vivax
• P. ovale
• P. malariae.

P. vivax and P. falciparum arethe most common and P. falciparum is the most deadly type of malaria infection.

Today malaria is found throughout the tropical and sub-tropical regions of the world and causes more than 300 million acute illnesses and at least one million deaths annually.²⁵ Plasmodium falciparum malaria is most common in Africa, south of the Sahara, accounting in large part for the extremely high mortality in this region.

The majority of cases and almost all deaths are caused by Plasmodium falciparum. Plasmodium vivax, Plasmodium ovale and Plasmodium malariae cause less severe disease. Over 90% of all malaria cases occur in Africa, and most are caused by P. falciparum. This species also predominates in Haiti and the Dominican Republic. In Mexico, Central and South America, the Mediterranean, Asia and Oceania, both P. falciparum and P. vivax are endemic. Disease caused by P. ovale and P. malariae is relatively rare.²⁶