Malaria is caused by Plasmodium parasites. Four Plasmodium species (Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae) give disease in humans, and humans are their only relevant reservoir.
Transmission requires an intermediate mosquito (anopheles) host, which is found worldwide. Following exposure (an infected mosquito bite) the incubation period varies between one and four weeks in most cases. Depending on the plasmodium species involved, much longer incubation periods are possible.
Once the Plasmodia multiply inside the red blood cells, fever and multi-organ disease may ensue, which can be life-threatening when P. falciparum is involved. Symptoms are much reduced if the patient is semi-immune by repeated previous infection. Several drugs are available for both treatment and prophylaxis.
During the 20th century, malaria was eradicated from many temperate areas, including the whole of the EU. As a result, the disease is now essentially limited to tropical countries. With global climate change, the potential for the reappearance of malaria in countries where it was previously eradicated exists but is relatively small. Anopheles mosquitoes are in fact still present in those areas, including in Europe.
Due to the large number of imported cases in Europe, malaria is mainly a travel medicine issue. Nonetheless, ‘airport malaria’ is sometimes reported in relation to the inadvertent transport of infected mosquitoes from endemic areas.