A woman walks past a banner placed around the perimeter of the Rand Afrikaans University in Johannesburg on World AIDS Day. The university used the banner to raise public awareness about AIDS and the devastating toll the disease has had in South Africa. Paul Botes/AP Photo hide caption

itoggle caption Paul Botes/AP Photo

A health worker injects a woman with a shot of Depo Provera, a quarterly contraceptive injection, at a health clinic in Busia, Uganda, in 2009. MCT/MCT via Getty Images hide caption

itoggle caption MCT/MCT via Getty Images

Virologists and other scientists are meeting at the World Health Organization's Geneva headquarters to talk about the bird flu. Pierre Virot/WHO hide caption

itoggle caption Pierre Virot/WHO

Haitians suffering from cholera symptoms rest at the treatment center in Mirebalais, a dusty town north of Port-au-Prince, Haiti, last June. The cholera epidemic in Haiti began in Mirebalais, believed to be the result of overflowing bathrooms from a nearby U.N. compound. Eduardo Verdugo/AP hide caption

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A man from Liberia uses a pump to adjust his liquid silicon lens. Liquid-lens glasses are part of an effort to make eyewear more accessible in the developing world. Courtesy of Centre for Vision in the Developing World hide caption

itoggle caption Courtesy of Centre for Vision in the Developing World

Many over-the-counter contraceptives contain a spermicide known as nonoxynol-9. Gretchen Cuda Kroen/For NPR hide caption

itoggle caption Gretchen Cuda Kroen/For NPR

Chhay Meth, 9, suffering through an attack of malaria at the family's home in O'treng village on the outskirts of Pailin, Cambodia, in 2009. A drug-resistant form of malaria in the region medical led officials to declare a health emergency. David Longstreath/AP hide caption

itoggle caption David Longstreath/AP

Dr. Dan Shuman (right), who was recruited to the Ashland Health Clinic as part of its mission-focused medicine program, consults with a patient about smoking cessation. Peggy Lowe/Harvest Public Media hide caption

itoggle caption Peggy Lowe/Harvest Public Media

An artist on Rio de Janeiro's Copacabana beach puts the final touches on a sand sculpture of the assassin bug, which spreads Chagas disease. The sculpture was part of an event in 2009 commemorating the 100th anniversary of the discovery of the disease. Vanderlei Almeida/AFP/Getty Images hide caption

itoggle caption Vanderlei Almeida/AFP/Getty Images