Malaria is caused by Plasmodium parasites transmitted via mosquito bites. The parasites travel to the liver and multiply, then infect red blood cells. Symptoms include fever, chills, and fatigue. Diagnosis involves examining blood smears under a microscope for parasites. Treatment depends on the parasite species and disease severity, but typically involves antimalarial medications such as chloroquine or artemisinin combinations. Complications can include severe anemia, respiratory distress, kidney and liver damage.