An Afghan health worker administers the polio vaccine to a child during a vaccination campaign in Kabul, Afghanistan, in 2010. Majid Saeedi/Getty Images hide caption

itoggle caption Majid Saeedi/Getty Images

A study of Ugandans found antiretroviral drugs can extend the lifespans of people with HIV to nearly normal lengths. Adek Berry/AFP/Getty Images hide caption

itoggle caption Adek Berry/AFP/Getty Images

Mourners attend a memorial service for recent cholera victims in Haiti that took place Wednesday in Savanette, an isolated community in the mountains outside Mirebalais, Haiti. Cate Oswald/Partners in Health hide caption

itoggle caption Cate Oswald/Partners in Health

Bottles of antiretroviral drug Truvada, a medicine used in trials that showed a reduction in transmission of HIV between heterosexuals. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images

Doheny Beach in Orange County, Calif. photographed in 2005. A new report on the nation's beaches found that Doheny exceeded at least one water quality standard 42 percent of the time it was tested in 2010. Flickr hide caption

itoggle caption Flickr

Reinhard Burger, president of the Robert Koch Institute, tells reporters in Berlin Friday that sprouts from a German farm are the cause of the country's massive foodborne illness outbreak. Michele Tantussi/AP hide caption

itoggle caption Michele Tantussi/AP

A closeup view of the bacterium behind the foodborne disease outbreak centered in Germany. Manfred Rohde/Getty Images hide caption

itoggle caption Manfred Rohde/Getty Images

Greenhouses of the shuttered Gaertnerhof Bienenbuettel organic farm in Bienenbuettel, Germany. Health authorities in the German state of Lower Saxony closed the farm over worries that the vegetable sprouts grown there could be a source of E. coli outbreak that has infected more than 2,300 people. But preliminary tests came back negative. Joern Pollex/Getty Images hide caption

itoggle caption Joern Pollex/Getty Images