I.

Introduction

Malaria, disease caused by infection with single-celled parasites of the genus Plasmodium. Anopheles mosquitoes transmit these parasites from one person to another in their bites. Malaria is characterized by periodic bouts of severe chills and high fever. Serious cases of malaria can result in death if left untreated. More than a million people die of the disease each year, most of them in Africa, according to the World Health Organization (WHO).

Malaria was once widespread in North America and other temperate regions. Today, the disease occurs mostly in tropical and subtropical regions, particularly in sub-Saharan Africa and Southeast Asia. The disease is also found in Central and South America, Oceania, and on some Caribbean islands. Public health officials had hoped to wipe out malaria during the 20th century. However, malaria parasites have developed defenses against many antimalarial drugs. This response, known as drug resistance, makes the drugs less effective. In addition, the Anopheles mosquitoes that transmit the disease have become resistant to many insecticides.

Malaria remains a global health problem, and public health efforts today focus on controlling it. In addition, a worldwide effort is under way to develop a vaccine that protects people against the disease. In the meantime, research by the WHO has found that sleeping under bed nets treated with insecticide can greatly reduce deaths from malaria, especially among children.