Malaria is a common infection in hot, tropical areas but can also occur in moderate climates. Malaria is an infectious disease which causes about 350-500 million infections with humans and approximately 1.3 - 3 million deaths annually. India is one of the malaria endemic regions of the world. Worldwide, 300-500 million people are infected with malaria each year. Malaria is more common in rural areas than in cities; this is in contrast to dengue fever where urban areas present the greater risk. Certain mosquito species transmit malaria to birds. Malaria is caused by the protozoan parasites of the genus Plasmodium (of the phylum Apicomplexa), and the transmission vector for human malarial parasite is the female Anopheles mosquito.

Only females feed on blood, thus males do not pass on the disease. The Anopheles species prefer to feed at night. Young mosquitoes first ingest the malaria parasite by feeding on a human carrier. Infected female Anopheles mosquitoes carry Plasmodium sporozoites in their salivary glands. When an infected mosquito pierces a person's skin to take a blood meal, the sporozoites in the mosquito's saliva enter the bloodstream and migrate to the liver. Within the red blood cells they multiply further, again asexually, periodically breaking out of the exploited red blood cells to invade fresh red blood cells and start the amplification cycle anew. The classical description of waves of fever coming every two (Plasmodium falciparum) or three days (Plasmodium vivax) arises from simultaneous waves of merozoites breaking out of red blood cells during the same day.

The diagnosis of malaria is microscopic examination of blood films because each of the four major parasite species has distinguishing characteristics. Once malaria parasites enter the bloodstream, they travel to the liver and multiply. Every few days, thousands of parasites are released from the liver into the blood, where they destroy red blood cells. Some parasites also remain in the liver and continue to multiply, releasing more parasites into the blood every few days. The incubation period for malaria is the time between the mosquito bite and the release of parasites from the liver. This varies, depending on which malaria parasite is causing the disease. In general, it can range from 10 days to a month.

Symptoms of malaria include fever, shivering, joint pain, vomiting, anemia and convulsions. There may be the feeling of tingling in the skin, particularly with malaria caused by P. falciparum. Consequences of infection with malaria include coma and death if untreated. Young children and pregnant women are especially vulnerable. Splenomegaly (enlarged spleen), severe headache, cerebral ischemia and hemoglobinuria with renal failure may occur.

There are several types of drugs used to treat malaria. Chloroquine was the antimalarial drug used to treat malaria.. Some currently available anti-malarial drugs are Artesunate-amodiaquine, Atovaquone-proguanil, Quinine, Chloroquine ,Doxycycline, Mefloquine,Primaquine . The disease remains a threat to people living in endemic areas who have no proper and prompt access to effective drugs. Access to pharmacies and health facilities, as well as drug costs, are major obstacles. There is a problem of availability of effective malaria treatments in many parts of India. Methods used to prevent the spread of disease, or to protect individuals in areas where malaria is endemic, include prophylactic drugs, mosquito eradication, and the prevention of mosquito bites. There is currently no vaccine that will prevent malaria, but this is an active field of research.