Malaria Overview

Reviewed: May 8, 2014

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.

Malaria Symptoms

According to the World Health Organization (WHO), the first symptoms of malaria are fever, headache, chills and vomiting. These symptoms may be mild and difficult to recognize as malaria. If not treated within 24 hours, malaria can progress to severe illness often leading to death.

The WHO states that children with severe malaria frequently develop one or more of the following symptoms: severe anaemia, respiratory distress in relation to metabolic acidosis, or cerebral malaria. In adults, multi-organ involvement is also frequent. In malaria endemic areas, persons may develop partial immunity, allowing asymptomatic infections to occur.

Malaria Causes

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 falciparumPlasmodium vivaxPlasmodium ovale and Plasmodium malariaePlasmodium 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.

Malaria Diagnosis

If you think you may have malaria then you need see your health care provider right away. If you have travelled to an area where malarial transmission occurs in the past year, then you may be at risk of this disease, even if you took anti-malarial medication when you were traveling.

Your health care provider will perform a blood test. The blood sample will be sent to the laboratory and will be examined microscopically for the presence of the malaria parasite. The type of malaria causing the infection will also be determined. If the first blood test is negative but your doctor suspects you have malaria, then you may be asked to have another further blood tests taken.

During a physical examination, the doctor may find an enlarged liver or enlarged spleen.

Antigen detection tests, which require a very small amount of blood, are sometimes used when microscopic examination is unavailable.

A complete blood count (CBC) will identify anemia if it is present.

Malaria Treatments

If malaria is treated rapidly, most people fully recover.

Malaria is normally treated using antimalarial medicines. Chloroquine is often used as an antimalarial medication. However, chloroquine-resistant infections are common in some parts of the world.

Possible treatments for chloroquine-resistant infections include:

The choice of medication depends in part on where you were when you were infected.

Malaria Other Treatments

Medical care, including fluids through a vein (IV) and other medications and breathing (respiratory) support may be needed.

Malaria Prognosis

The outcome is expected to be good in most cases of malaria with treatment, but poor in Falciparum infection with complications.