10 Diseases That Used to Be Death Sentences

A girl with a high fever gets tested for malaria at the CARE medical clinic at the Yida refugee camp along the border between North Sudan and South Sundan. Paula Bronstein/Getty Images

Mosquitos pack the potential for more than just annoying, itchy red bumps. In fact, they transmit the Plasmodium parasite that causes malaria, which is characterized by chills, sweating and fever, among other symptoms [source: National Institute of Allergy and Infectious Diseases]. Although it has been largely eradicated in North America, the Caribbean and much of Europe, malaria is still a serious concern in tropical and subtropical countries, particularly in Africa and Asia.

Public health initiatives have rendered malaria both preventable and treatable, as long as it's done correctly and quickly. Rapid diagnostic tests, followed by tailored antimalarial treatments have saved at least 3 million lives since 2000. Between 2000 and 2013, global deaths from malaria have fallen 42 percent [source: WHO]. As with most of these diseases, prevention with such new technologies as insecticide-treated bed nets is encouraged by infectious disease experts [source: Haynes].