Malaria is defined as an intermittent and remittent fever caused by a protozoan parasite that invades the red blood cells. According to HealthLine, Once the parasites are inside the body, they travel to the liver, where they mature. After several days, the mature parasites enter the bloodstream and begin to infect red blood cells. Within 48 to 72 hours, the parasites inside the red blood cells multiply, causing the infected cells to burst open. The parasites continue to infect red blood cells, resulting in symptoms that occur in cycles that last two to three days at a time. Malaria is typically found in tropical and subtropical climates where the parasites can live. The World Health Organization (WHO) estimates that about 3.2 billion people are at risk of malaria. In the United States, the Centers for Disease Control and Prevention (CDC) report 1,500 cases of malaria annually. Most cases of malaria develop in people who travel to countries where malaria is more common. Malaria can be caused by a mosquito bite or if an infected mother spreads the disease to her baby. Only female mosquitoes spread the malaria parasites. When a mosquito bites a person who already has malaria, it sucks up the person’s blood, which contain the parasites. When the mosquito bites its next victim, it injects the parasites into that person. It can also be transmitted by organ transplant, use of shared needles, and transfusion. The symptoms of malaria typically develop within 10 days to four weeks following the infection. In some people, symptoms may not develop for several months. Some malarial parasites can enter the body but will be dormant for long periods of time. Symptoms include shaking chills that range from moderate to severe, headache, nausea, vomiting, diarrhea, anemia, muscle pain, sweating, high fever, convulsions, coma, and blood stool. People with malaria who receive treatment typically have a good long-term outlook. If complications arise as a result of malaria, the outlook may not be as good. Cerebral malaria, which causes swelling of the blood vessels of the brain, can result in brain damage. The long-term outlook for patients with drug-resistant parasites may also be poor. In these patients, malaria may recur. This may cause other complications. If drugs are not available or if the parasites are resistant to them, malaria infection can develop to anemia, hypoglycemia or cerebral malaria, in which capillaries carrying blood to the brain are blocked. Cerebral malaria can cause coma, life-long-learning disabilities, and death.