Malaria is caused by Plasmodium parasites transmitted via mosquito bites. It causes cycles of fever, chills and sweating. Most cases are in tropical areas like Africa and India. Diagnosis involves blood smears under microscope or antigen detection tests. Treatment depends on parasite species and severity, using drugs like chloroquine, artemisinins, atovaquone or primaquine. Prevention involves mosquito nets, repellents and eliminating breeding sites.