Malaria is one of the world's leading infectious diseases, killing up to 500 million people every year and killing up to 3 million people. By traveling to Asian and African countries, malaria also plays a role in Germany, although the malaria parasites are not native to Germany.
Malaria is an infectious disease with typical fevers, which is triggered by malaria pathogens, the plasmodia. These plasmodia are transmitted to humans by a specific mosquito, the Anopheles mosquito.
Spread of malaria
Malaria is typical of tropical and subtropical areas.
Most of the infections occur in Africa, from sub-Saharan Africa to the north of South Africa - WHO estimates that between 300 and 500 million people are infected with it every year and more than one million children die.
In Asia, especially the border region between Thailand and Myanmar, Laos, Cambodia, the Indonesian islands east of Bali, Papua New Guinea and the Solomon Islands are affected.
In South America, parts of Brazil are endangered. However, tourism also affects people who do not actually live in the risk areas. In recent years, several hundred Germans have been infected on holiday trips every year.
Most of these infections occurred in West African countries and Kenya. It is extremely rare to get infected if an infected mosquito gets into an airplane. Then it can come in the plane or at the airport to a transfer, the airport malaria. Most malaria is transmitted through the bite of a female Anopheles mosquito that is infected with plasmodia.
Very rarely, malaria can also be transmitted from person to person during a blood transfusion or during pregnancy from the mother to the unborn child. Also, "healthy" mosquitoes can be infected by sucking human blood infested with malaria parasites and thus become carrier mosquitoes - that has already happened.
Emergence of malaria
Malaria is caused by four different types of plasmodium - Plasmodium falciparum, ovale, vivax and malariae. These four types cause three types of malaria, which differ in terms of fever history and disease severity.
The plasmodia spend part of their life cycle in the mosquito and the other part in the human. Their development in humans is closely related to the fever episodes that occur in malaria. Through the bite of the infected with plasmodia mosquito enter the pathogens in the bloodstream of humans. They migrate to the liver, where they stay between 5 and 18 days depending on the species and evolve.
At the end of this stage, the affected liver cells burst open and the malaria parasites re-enter the bloodstream. There they cling to red blood cells (erythrocytes), penetrate into them and multiply on. When the erythrocytes disintegrate, so many pathogens are released, which in turn infect new red blood cells. This mechanism causes the recurrent fever episodes.