Timothy Webb and other advocates protest the cost of HIV drugs manufactured by the pharmaceutical company Gilead outside an AIDS conference in Atlanta in March. Gilead is making a new hepatitis C drug, Sovaldi. John Amis/AP Images for AIDS Healthcare Foundation hide caption

itoggle caption John Amis/AP Images for AIDS Healthcare Foundation

Sun, shopping and chikungunya? A nasty virus has sickened 10 people on the island of St. Martin in the past few months. Balalaika/iStockphoto hide caption

itoggle caption Balalaika/iStockphoto

A mother waits with her child at an HIV clinic in Nyagasambu, Rwanda, in February 2008. The clinic was built with a grant from the President's Emergency Plan for AIDS Relief initiative. Shashank Bengali/MCT /Landov hide caption

itoggle caption Shashank Bengali/MCT /Landov

There's no evidence that triclosan and other chemicals in antibacterial soaps do a better job than plain soap and water, the FDA says. Kiichiro Sato/AP hide caption

itoggle caption Kiichiro Sato/AP

A polio worker vaccinates a child in Khyber-Pakhtunkhwa province, Pakistan, in October. Arshad Arbab/EPA/Landov hide caption

itoggle caption Arshad Arbab/EPA/Landov

The chikunguyna virus was discovered in 1955 by two scientists in Tanzania. EMDataBank using UCSF Chimera hide caption

itoggle caption EMDataBank using UCSF Chimera

Children get tested for malaria at a clinic near the Myanmar border in Sai Yoke, Thailand. Drug-resistant strains of the parasite have appeared in the region over the past few years. Surkree Sukplang/Reuters /Landov hide caption

itoggle caption Surkree Sukplang/Reuters /Landov

The interior of the nose is like a lush rain forest that's barely been explored. Courtesy of Sunje Pamp hide caption

itoggle caption Courtesy of Sunje Pamp

The Ivy League school has begun vaccinating nearly 6,000 students to try to stop an outbreak of type B meningitis in an unusual federal government-endorsed administration of a drug not generally approved for use in the U.S. Mel Evans/AP hide caption

itoggle caption Mel Evans/AP

A colorized closeup of the hepatitis C virus. James Cavallini/Science Source hide caption

itoggle caption James Cavallini/Science Source

Administrators at University of California, Santa Barbara are encouraging fraternities and sororities to hold off on parties. Damian Gadal/Flickr hide caption

itoggle caption Damian Gadal/Flickr

Six students and a visitor have fallen ill with meningitis at Princeton University in New Jersey, shown here in August 2013. All have recovered or are recovering, officials said. Bloomberg via Getty Images hide caption

itoggle caption Bloomberg via Getty Images

Yoset, a spiritual healer near Arua, Uganda, works with the Centers for Disease Control and Prevention to detect the plague in his village. Courtesy of Mary Hayden hide caption

itoggle caption Courtesy of Mary Hayden

Urine tests are the gold standard for diagnosing bladder infections. But one common test, the urine culture, can easily miss infections. Ian Hooton/http://www.sciencesource.com/ hide caption

itoggle caption Ian Hooton/http://www.sciencesource.com/