Malaria is a mosquito-borne, as well as a blood-borne, disease. Although it can be fatal, it is now also largely preventable through prophylactic medication. Most cases are heavily concentrated in Africa at present, but the disease also still occurs throughout the Middle East; South, East, and Southeast Asia; Oceania; and Latin America.

Malaria is caused by several species of the parasite Plasmodium, which is transmitted to humans through the mosquito Anopheles. These mosquitoes usually bite at night, but can also bite during early evening or morning. At environmental temperatures below 20 degrees Celsius, Plasmodium falciparum (the species known to cause severe malaria) is unable to complete its growth cycle in the Anopheles mosquito, and thus cannot be transmitted to humans. This explains why most cases of malaria occur in the warmer parts of the world. However, because Plasmodium lives in the red blood cells, infected people can thus also transmit malaria to other people through blood transfusion, organ donation, sharing of syringes or needles, and from mother to infant before or during childbirth.

Although symptoms can appear as early as 7 days or as late as 1 year after infection, most people experience symptoms between 10 days to 4 weeks after infection. Typical symptoms resemble a flu-like illness, including fever, chills, headache and muscle aches, and tiredness. Nausea, vomiting, diarrhea, jaundice, and anemia can also occur. Malaria is also distinguishable for its “fever cycles” (a combination of chills, fever, and sweating), which can recur either every 48 or 72 hours depending on the species of Plasmodium. Severe malaria, however, can cause life-threatening organ failure, the manifestations of which can include kidney failure, seizures, bleeding, mental confusion, and coma. Sometimes, the parasite can also remain dormant in the liver, and after hibernation (which can take as long as 4 years), can reenter the bloodstream and start infecting red blood cells, making a person sick.

There are different combinations of medications given depending on the species of Plasmodium that has caused the disease. Thus, it is best to consult a physician once flu-like symptoms appear and do not easily resolve with home care, in order to determine the specific infectious agent through laboratory testing and provide the appropriate treatment.

Medical prophylaxis against malaria is now widely available and recommended when going to places with known widespread transmission. These prophylactic regimens take time to complete; thus, it is important to consult a doctor as early as possible to plan the regimen. Besides medical prophylaxis, preventive measures include the usual protocols with regards to mosquito-borne disease, such as using long-lasting insecticidal mosquito nets especially during nighttime, wearing long-sleeved clothing and pants especially when going outdoors, using mosquito repellants, and installing screens on doors and windows.