Malaria

Malaria is a long-lasting disease of the blood. It is transmitted to people by mosquitoes infected with the malaria parasite. The malaria parasite attacks the blood and causes recurring chills, fever, and sometimes jaundice and anemia. 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. No vaccine against malaria is available. Travelers can protect themselves by using anti-mosquito measures and by taking drugs to prevent 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. Malaria is caused by any one of four species of one-celled parasites, called Plasmodium.
The parasite is spread to people by the female Anopheles mosquito, which feeds on human blood. Although four species of malaria parasites can infect humans and cause illness, only malaria caused by Plasmodium falciparum is potentially life-threatening.Malaria transmission occurs in large areas of Central and South America, sub-Saharan Africa, the Indian subcontinent, Southeast Asia, the Middle East, and Oceania. The risk to travelers varies depending on local weather conditions, the number of mosquitoes in the area, and the traveler's itinerary and time and type of travel.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 parasites attack other red blood cells, and the cycle of infection continues, causing the common signs and symptoms of malaria.When a non-infected mosquito bites an infected person, the mosquito sucks up parasites from the person's blood. The mosquito is then infected with the malaria parasites. The parasites go through several stages of growth in the mosquito. When the mosquito bites someone else, that person will become infected with malaria parasites, and the cycle will begin again.Malaria parasites can also be transmitted by transfusion of blood from an infected person or by the use of needles or syringes contaminated with the blood of an infected person.

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.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. When infection occurs by blood transfusion, the time to the start of symptoms depends on the number of parasites in the transfusion. Malaria is diagnosed by a blood test to check for parasites.Anyone who lives in or travels to a country where there are malaria-infected people and mosquitoes is at risk.Malaria caused by Plasmodium falciparum can cause kidney or liver failure, coma, and death.