Malaria

Malaria is a sometimes fatal disease that involves high fevers, shaking chills, flu-like symptoms, and anemia. It is caused by a parasite that commonly infects a certain type of mosquito which feeds on humans. 

According to the CDC, approximately 1,500 cases of malaria are diagnosed in the United States each year, the majority of which are in travelers and immigrants returning from countries where malaria transmission occurs, many from sub-Saharan Africa and South Asia.

The disease is a major health problem in much of the tropics and subtropics, as the World Health Organization estimates that in 2010, 219 million clinical cases of malaria occurred, and 660,000 people died of malaria, most of them children in Africa.

Malarial infection is passed from human to human by the bite of infected Anopheles mosquitoes. Malaria can also be transmitted from a mother to her unborn baby (congenitally) and by blood transfusions. After infection, the parasites (called sporozoites) travel through the bloodstream to the liver, where they mature and release another form, the merozoites. The parasites enter the bloodstream and infect red blood cells.

There are four types of plasmodium that cause malaria. These are called Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae. Plasmodium falciparum is usually the most serious of the four.

The parasites multiply inside the red blood cells, which then break open within 48 to 72 hours, infecting more red blood cells. The first symptoms usually occur 10 days to 4 weeks after infection, though they can appear as early as 8 days or as long as a year after infection. The symptoms occur in cycles of 48 to 72 hours.

Seek medical care promptly for fever, chills, headache, or flu-like illness after travel to a malaria area, and tell your doctor where you traveled. Untreated malaria can become life-threatening within 24 hours, so do not delay.