Humans become infected with malaria, a serious and sometimes fatal disease, when they are bitten by a mosquito carrying one of the following five parasites: Plasmodium falciparum, P. vivax, P. ovale, P. malariae, or P. knowlesi. About 1,500 cases are diagnosed in the United States each year. Most are travelers or immigrants to the United States coming from places where malaria transmission occurs, including sub-Saharan Africa and South Asia.
The World Health Organization estimates that in 2015, an estimated 212 million people were infected with malaria worldwide, leading to about 429,000 deaths, most of which were young children in sub-Saharan Africa. Malaria mostly affects the world’s less developed nations, and it is part of the reason many of these countries are caught in a vicious cycle of disease and poverty.
Symptoms of malaria are similar to those of the flu—high fever, shaking chills, headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. Symptoms typically occur between 7 and 30 days after the initial mosquito bite. People with more serious cases may experience anemia, jaundice (yellow coloring of the skin and eyes), acute respiratory distress syndrome, and abnormalities in blood coagulation. If not treated promptly, the infection can become severe and may cause kidney failure, seizures, mental confusion, coma, and death.
Infections from P. vivax and P. ovale may recur, largely because these parasites may remain dormant in the liver. A subsequent attack may occur months or even years after the initial episode.
Malaria can be cured with prescription drugs. The type of drugs and length of treatment depend on the type of malaria parasite, the infection site, the infected person’s age and pregnancy status, and the severity of illness at the start of treatment.
There are effective prescription drugs that prevent as well as treat malaria infection. Typically, a health care provider will recommend a drug based on an individual’s travel plans, medical history, age, drug allergies, pregnancy status, and other factors. The Centers for Disease Control and Prevention has a list of all the places in the world
where malaria transmission occurs and the malaria drugs that are recommended for each location.
In some afflicted countries, public health efforts—such as the development of artemisinin-based combination therapy, distribution of insecticide-treated bed nets, and indoor residual spraying of insecticides—have reduced the number of malaria deaths.