Malaria is a serious tropical disease that can be fatal. It is endemic to more than 100 countries and kills more than 1 million people annually according to the World Health Organization (WHO). Many of the deaths occur after the first exposure of children to the parasite responsible for the disease. Travelers to these areas may also develop malaria with the potential of severe symptoms due to their lack of prior infection.

A single-cell parasite of the genus Plasmodium is responsible for malaria. It is transmitted primarily by mosquitoes and infects the liver and red blood cells. As the parasite spreads through the body, the disease typically progresses from chills to fever to profuse sweating. Symptoms may fade but are likely to recur after two to three days.

Five species of the Plasmodium parasite cause malaria. The severity and recurrence of malaria depend largely on which species caused the infection. Plasmodium falciparum can cause severe symptoms and complications and is responsible for the majority of malaria deaths. Infection by three other parasite species (P. vivax, P. malariae, P. ovale) leads to less severe symptoms, but they may live for years in the body without causing obvious disease. A fifth species, P. knowlesi, was once believed to be restricted to monkeys but is now known to also cause disease in humans.

Early diagnosis of malaria is important for proper treatment. Because of the disease’s potential severity, patients suffering from flu-like symptoms within a year of visiting an area where malaria is endemic should consult their physician. The disease may be confirmed by identifying the parasite in a blood sample. This also allows the specific parasite to be determined, which is important for prescribing the right medication for treatment.

Malaria can often be prevented, especially among travelers, by taking proper measures. Prophylactic, or preventative, antimalarial medicines taken before, during and after visiting an endemic area reduce the risk of being infected. Other efforts focus on reducing mosquito bites to prevent transmission. These include covering skin with clothing, using effective insect repellent and sleeping under bed netting.

Malaria is a disease endemic to many tropical and subtropical countries. While many adults in these areas may develop immunity to the disease-causing parasite, severe illness tends to affect children and travelers to these regions. With proper preventative measures, the risk to travelers of developing malaria is greatly reduced. The prognosis after infection can also be greatly improved with early diagnosis and treatment.