A celebration erupts in the streets of the Massessehbeh village on Friday, after President Ernest Bai Koroma officially ended Sierra Leone's largest remaining Ebola quarantine. Sunday Alamba/AP hide caption

itoggle caption Sunday Alamba/AP

The varicella zoster virus causes chickenpox in children, then lurks in the body for years and can cause painful shingles later in life. James Cavallini/Science Source hide caption

itoggle caption James Cavallini/Science Source

The outbreak of Middle East respiratory syndrome is slowing down in South Korea, but people were still wearing surgical masks around Seoul on Monday. Ed Jones/AFP/Getty Images hide caption

itoggle caption Ed Jones/AFP/Getty Images

Raymond Wang, 17, of Vancouver, celebrates winning first place at the Intel International Science and Engineering Fair in Pittsburgh, May 15. Courtesy of Kathy Wolfe/Intel hide caption

itoggle caption Courtesy of Kathy Wolfe/Intel

In front of the emergency room at the Samsung Medical Center in Seoul, medical workers care for a man suspected of having the Middle Respiratory syndrome on Monday. Jung Yeon-Je/AFP/Getty Images hide caption

itoggle caption Jung Yeon-Je/AFP/Getty Images

Of I Wish You the Sunshine of Tomorrow, Rodgers says: "The ICU room my dad was in on the day he died had yellow walls. Every time we visited him we had to wear hospital gowns that were a bright yellow. [It] was a recurring color in that whole time frame of my life." Courtesy of Jennifer Rodgers hide caption

itoggle caption Courtesy of Jennifer Rodgers

Health worker Jackie Carnegie delivers a rubella vaccine in Colorado in 1972. Ira Gay Sealy/Denver Post via Getty Images hide caption

itoggle caption Ira Gay Sealy/Denver Post via Getty Images

Rod-shaped specimens of Yersinia pestis, the bacterial cause of plague, find a happy home here in the foregut of a flea. Fleas can transmit the infection to animals and people, who can get pneumonic plague and transmit the infection through a cough or kiss. Science Source hide caption

itoggle caption Science Source