What is malaria?

Malaria is a serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of mosquito which feeds on humans.

People who get malaria are typically very sick with high fevers, shaking chills, and flu-like illness.

Four kinds of malaria parasites infect humans: Plasmodium falciparum, P. vivax, P. ovale, and P. malariae. In addition, P. knowlesi, a type of malaria that naturally infects macaques in Southeast Asia, also infects humans, causing malaria that is transmitted from animal to human (“zoonotic” malaria). P. falciparum is the type of malaria that is most likely to result in severe infections and if not promptly treated, may lead to death.

Although malaria can be a deadly disease, illness and death from malaria can usually be prevented.

Globally, the World Health Organization estimates that in 2019, 229 million clinical cases of malaria occurred, and 409,000 people died of malaria, most of them children in Africa. Because malaria causes so much illness and death, the disease is a great drain on many national economies. Since many countries with malaria are already among the poorer nations, the disease maintains a vicious cycle of disease and poverty.

How is malaria transmitted?

Usually, people get malaria after being bitten by an infectious female anopheles mosquito. Only Anopheles mosquitoes can transmit malaria and must have been infected by a previous blood meal from an infected person. When a mosquito bites an infected person, a small amount of blood containing microscopic malaria parasites is drawn. About a week later, when the mosquito has its next blood meal, these parasites mix with the mosquito’s saliva and are injected into the bitten person.

Because the malaria parasite is found in the red blood cells of an infected person, malaria can also be transmitted through blood transfusions, organ transplants, or sharing needles or syringes that are contaminated with blood. Malaria can also be transmitted from a mother to her unborn child before or during delivery (“congenital” malaria).