Malaria is a leading cause of death and disease worldwide, especially in developing countries. Each year, an estimated 300 to 500 million cases occur, and more than 1 million people die of the disease annually. Although malaria can be a fatal disease, in many cases, death can be prevented with proper and prompt treatment.
The cause of malaria is an infection with a parasite.
Plasmodium is the name for the species of microscopic parasites that cause the disease
(see Malaria Causes). There are over 100 species of
Plasmodium, which can infect animal species, such as:
- Reptiles
- Birds
- Various mammals.
Only four species of Plasmodium infect humans in nature. These four types include:
- Plasmodium falciparum
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae.
Malaria is usually transmitted through the bite of an infected female
Anopheles mosquito. Less commonly, the disease is spread through contact with infected blood.
Malaria is not transmitted from person to person, like the
common cold or the flu. You cannot get the disease from casual contact with infected people.
When a person becomes infected with one of the
Plasmodium parasites that cause malaria, he or she will not feel sick immediately. For most people, the incubation period (the period between infection and the onset of symptoms) ranges from ten days to four weeks after the bite from the infected
Anopheles mosquito; however, the incubation period can be as short as seven days or as long as several years.
Infection with malaria parasites may result in a wide variety of symptoms, ranging from mild symptoms to severe disease and even death. Malaria can be categorized as uncomplicated or severe (complicated).
Some common early or uncomplicated symptoms include the following:
- Fever
- Sweats
- Shaking chills
- Headaches
- Tiredness
- Muscles aches
- Nausea and vomiting
- Diarrhea.
(Click Malaria Symptoms for information about more severe symptoms that may develop in some cases of the disease.)
Although this doesn't occur very frequently, malaria signs and symptoms may follow a cyclical pattern. In these cases, symptoms last for 6 to 10 hours and then get better. Every two to three days, depending on the type of parasite, the symptoms return.
In order to make a diagnosis of malaria, your healthcare provider will likely ask a number of questions and perform a physical exam, looking for signs or symptoms of the disease. He or she may also order certain tests to help in making a diagnosis.
The key to
malaria treatment is starting early. With early treatment, the disease can be cured and its serious effects can be prevented. If treatment is delayed, it can be a severe, potentially fatal disease (especially when caused by
Plasmodium falciparum).
The specific treatment that is recommended will depend on:
- The type (species) of the infecting parasite
- The area where the infection was acquired
- The severity of malaria symptoms
- The person's age
- Any other illnesses or conditions
- For a woman, if she is pregnant
- Drug allergies
- Other medications that are being taken.
Treatment always involves medication. The specific medicine prescribed will depend on the factors listed previously.
How Common Is the Disease?
The World Health Organization (WHO) estimates that each year 300 to 500 million cases of malaria occur and more than 1 million people die of the disease during that period. About 1,300 cases of malaria are diagnosed in the United States each year. The vast majority of cases in the United States are in travelers and immigrants returning from risky areas, many from sub-Saharan Africa and the Indian subcontinent.
Malaria in the United States
Malaria was eradicated from the United States in the early 1950s; however, the disease is common in many developing countries, and travelers who visit these areas risk getting it.
Returning travelers and arriving immigrants could also reintroduce the disease in the United States. The mosquito that transmits malaria,
Anopheles, is found throughout much of the United States. If local
mosquitoes bite an infected person, those mosquitoes can, in turn, infect local residents. This is known as introduced malaria.
The
history of malaria, or a disease resembling it, goes back many thousands of years. In fact, malaria has been noted for more than 4,000 years, and has probably influenced human populations and human history to a great extent.
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