Malaria

Malaria has been described as the world's greatest public health problem. It is caused by one of several strains of the Plasmodium protozoan, a one-celled parasite that is transmitted by the bite of the Anopheles mosquito. Hundreds of millions of persons are struck by malaria each year, resulting in 1–3 million deaths annually, primarily in children under five-years-old in sub-Saharan Africa, where 90% of malaria deaths occur. Malaria has essentially been eradicated in North America, Europe, and Russia, although infected travelers and immigrants can reintroduce the disease if bitten by an infected mosquito. Malaria is on the increase worldwide and presents a major burden for tropical communities and travelers, particularly in areas where the parasite has evolved resistance to the drugs used to treat it.