A parasitic disease
Malaria (muh-LAIR-ee-uh) is a blood disease caused by parasites transmitted by mosquitoes. Rare in the developed world, malaria is very common in poorer nations. For folks living in the US, the main risk comes from traveling to countries where malaria is a problem.
Travelers heading to areas where malaria is common can help protect themselves by taking anti-malarial drugs However, there is no vaccine to provide long-term immunity from the disease. The best protection is to take anti-mosquito measures such as wearing long-sleeves and long pants, using insect repellent and sleeping under a bug net.
People with malaria typically have cycles of chills, fever and sweats that recur every one to three days. They may also suffer nausea, vomiting, diarrhea, anemia (destruction of red blood cells) and jaundice (yellowing of the skin or whites of the eyes). Symptoms may re-occur months or years later. Some malaria parasites can cause kidney or liver failure, coma and even death.
Malaria is caused by a parasite carried by mosquitoes. During a bite, these microbes enter the person's bloodstream and travel to the liver where they develop further. From there, they invade red blood cells, growing and multiplying until the cells burst, releasing thousands more parasites. Malaria can also be transmitted by transfusion of infected blood or by using infected needles.