Malaria is a disease caused by a parasite that can infect people's red blood cells. The parasite is spread to people by the bites of infected mosquitoes.

Most malaria infections cause flu-like symptoms (such as high fever, chills, muscle pain, and diarrhea) that come and go in cycles. A serious form of malaria can cause serious heart, lung, kidney, and brain problems, or death.

Many malaria cases occur in people who have traveled to developing countries (especially Africa). A person can reduce the risk of malaria by taking steps to prevent mosquito bites and by taking preventive medicine that reduces the risk of infection in case the person is bitten by an infected mosquito. Medicines are also used to treat malaria.

Malaria can persist for years. A person may have repeated cycles of illness.