Malaria

Malaria is by far the world’s most important tropical parasitic disease. An estimated 300 – 500 million people become ill each year. Malaria is due to infection with the Plasmodium parasite, a small single cell organism. In principle 4 Plasmodium species can cause disease in humans, but infections with P. falciparum are the most important. The disease kills an estimated two - three million people per year, mainly young children in developing countries. Approximately 1 child dies every 30 seconds due to malaria. Other important risk groups are pregnant women and non-immune travellers.

Transmission of the parasites from man to man occurs via the bite of infected blood-feeding female mosquitoes (Anopheles). Inside the human body, the malaria parasites multiply extremely rapidly in the liver. At a certain time point, they leave this organ and subsequently infect red blood cells (erythrocytes). A next wave of Plasmodium replication takes place in the erythrocytes, then the red blood cell bursts, followed by infection of new red blood cells by the parasites. Malaria begins as a flu-like illness 8 - 30 days after infection. Symptoms include fever, with or without other symptoms like headache, pain in the muscles, vomiting, diarrhoea and cough. Typical cycles of fever with shaking chills and drenching sweats may develop. Destruction of the erythrocytes leads to severe anaemia. Death may be due to infected red blood cells blocking blood vessels in the brain (cerebral malaria) or damage to other vital organs (e.g. liver and kidneys).

Prompt, accurate diagnosis and effective treatment are corner stones of effective malaria management. Clinical diagnosis is not always very easy, as primary symptoms may resemble those of other diseases (flu). Therefore, laboratory diagnosis is very important and this has up to now relied almost exclusively on microscopy.

Malaria is in principle a curable disease. However, the parasite is capable of becoming resistant to the action of anti-malaria drugs. This is due to small changes in the parasite DNA. Over-prescription of anti-malarials (confusion with other febrile diseases) and uncontrolled selling of poor quality drugs contribute to the increase in drug resistant parasites. There is a big need to develop and test new anti-malaria drug(s) or drug combinations.