Everything you wanted to know about Malaria
What is malaria? - Malaria is a disease of the blood that is transmitted to people by infected mosquitoes. Malaria is very common throughout the world. In the United States, the main risk is to persons traveling to tropical and subtropical countries where malaria is a problem.
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How is malaria spread? A person gets malaria from the bite of an infected female mosquito. The mosquito bite injects young forms of the malaria parasite into the person's blood. The parasites travel through the person's bloodstream to the liver, where they grow to their next stage of development. In 6 to 9 days, the parasites leave the liver and enter the bloodstream again. They invade the red blood cells, finish growing, and begin to multiply quickly. The number of parasites increases until the red blood cells burst, releasing thousands of parasites into the person's bloodstream. The parasites attack other red blood cells, and the cycle of infection continues, causing the common signs and symptoms of malaria.
What are the signs and symptoms of malaria? People with malaria typically have cycles of chills, fever, and sweating that recur every 1, 2, or 3 days. The attack of the malaria parasites on the person's red blood cells makes the person's temperature rise and the person feel hot. The subsequent bursting of red blood cells makes the person feel cold and have hard, shaking chills. Nausea, vomiting, and diarrhea often go along with the fever. The destruction of red blood cells can also cause jaundice (yellowing of the skin or whites of the eyes) and anemia.
How soon after exposure do symptoms appear? The time between a mosquito bite and the start of illness is usually 7 to 21 days, but some types of malaria parasites take much longer to cause symptoms.
How is malaria diagnosed? Malaria is diagnosed by a blood test to check for parasites.
What complications can result from malaria? Malaria caused by Plasmodium falciparum can cause kidney or liver failure, coma, and death. Although infections with other malaria parasites cause less serious illness, parasites can remain inactive in the liver and cause a reappearance of symptoms months or even years later.
What is the treatment for malaria? The treatment for malaria depends on where a person is infected with the disease. Different areas of the world have malaria types that are resistant to certain medicines. The correct drugs for each type of malaria must be prescribed by a doctor. Infection with Plasmodium falciparum is a medical emergency. About 2% of persons infected with falciparum malaria die, usually because of delayed treatment.
How common is malaria? Worldwide, an estimated 200 million to 300 million malaria infections occur each year, with 2 million to 3 million deaths. About 1,200 cases of malaria are diagnosed in the United States each year. Most are in persons entering the country for the first time or returning from foreign travel.
How can malaria be prevented? No vaccine against malaria is available. Travelers can protect themselves by using anti-mosquito measures and by taking drugs to prevent malaria. Avoiding the bites of Anopheles mosquitoes is the best way to prevent infection. Because Anopheles mosquitoes feed at night, malaria transmission happens mainly between dusk and dawn. Use insect repellent on exposed skin. The most effective repellents contain 20% to 35% DEET (N,N-diethylmethyltoluamide). Follow application instructions carefully when using these products.Take anti-malaria drugs -- When traveling to an area known to have malaria, discuss your travel plans with a doctor well before departure. Medicines to prevent malaria are usually prescribed for persons traveling to areas where malaria is common. Travelers from different countries might receive different recommendations because of differences in the availability of medicines. Travelers visiting only cities or rural areas where there is no risk of malaria might not need preventive drugs. An exact itinerary is needed to decide on the right degree of protection.
To be sure that your anti-malaria drug helps protect you against malaria, you must follow the recommended doses and schedules exactly:
- Take pills on the same day each week, or, for pills to be taken daily, at the same time each day.
- Take pills after meals.
- Take the recommended doses 1 to 2 weeks before travel, throughout the trip, and for 4 weeks after leaving the area with malaria.
- Do not stop taking the pills after arriving home. Complete the full dosage.
