The Ebola virus causes a deadly form of hemorrhagic fever. Frederick Murphy/CDC hide caption

itoggle caption Frederick Murphy/CDC

"You've been condomized!" said Joy Lynn Alegarbes, of The Condom Project, which promoted safe sex at the 19th International AIDS Conference. The group handed out more than 850,000 condoms this week. Benjamin Morris/NPR hide caption

itoggle caption Benjamin Morris/NPR

Anti-AIDS posters at the Eshowe public health clinic in Kwazulu Natal, South Africa. Clinicians there are hoping to slow the spread of HIV by getting more people treatment. Jason Beaubien /NPR hide caption

itoggle caption Jason Beaubien /NPR

A 3-D model of HIV peeled back to show its layers. HIV's genetic material sits inside a spherical shell (gray matrix) studded with spikes (dark gray and orange). The sphere pops open when a T cell tugs on a spike. Courtesy of Ivan Konstantinov/© Visual Science 2011 hide caption

itoggle caption Courtesy of Ivan Konstantinov/© Visual Science 2011

Researchers with HIV medication at a public research lab at the Oswaldo Cruz Foundation, or Fiocruz, in Rio de Janeiro. Jason Beaubien/NPR hide caption

itoggle caption Jason Beaubien/NPR

A lone pig roots through trash dumped over the side of a sewage canal that runs from the center of Port au Prince through Cite de Dieu. During the rainy season, the canal overflows its banks and fills nearby houses with sewage, which can carry cholera. John W. Poole /NPR hide caption

itoggle caption John W. Poole /NPR

A Cambodian doctor examines a child at Kantha Bopha Children's Hospital in Phnom Penh. Khem Sovannara/AFP/Getty Images hide caption

itoggle caption Khem Sovannara/AFP/Getty Images

Cambodian women wear masks as they walk in a market in Phnom Penh in Oct. 2009. That month a second Cambodian died from swine flu, health officials said. Tang Chhin Sothy/AFP/Getty Images hide caption

itoggle caption Tang Chhin Sothy/AFP/Getty Images

French surgeon Pierre Foldes in his Paris office in 2004. Foldes performs reconstructive surgery on women who have undergone genital mutilation. He recently authored a study on the long-term effects of the surgery. Jean Ayissi/AFP/Getty Images hide caption

itoggle caption Jean Ayissi/AFP/Getty Images

Gao Weiwei, a doctor of the Beijing Chest Hospital which specializes in the treatment of tuberculosis, talks to a patient suspected to have tuberculosis at the hospital in Tongzhou, near Beijing, March 27, 2009. Ng Han Guan/AP hide caption

itoggle caption Ng Han Guan/AP