A student gets vaccinated against pertussis at a Los Angeles middle school in 2012. The state required that students be immunized to halt an epidemic of whooping cough. Kevork Djansezian/Getty Images hide caption

itoggle caption Kevork Djansezian/Getty Images

A doctor takes an HIV test from an athlete during the 18th National Sports Festival in Lagos, Nigeria, last December. Sunday Alamba/AP hide caption

itoggle caption Sunday Alamba/AP

Inspector Mohammad Saleem Taqi takes a photo of sanitation workers as they clear out debris in sewers. The government feeds the photos into a map to track the city's effort to stop dengue fever. Beenish Ahmed/NPR hide caption

itoggle caption Beenish Ahmed/NPR

Kali Hardig, 12, was released from a hospital in Little Rock, Ark., on Sept. 11 after surviving a brain infection caused by amoebas. Danny Johnston/Associated Press hide caption

itoggle caption Danny Johnston/Associated Press

In 2010, Florida health officials looked for mosquito larvae in vehicle tires where water had collected. As many as 15 cases have been found in Stuart this year. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

A Cambodian boy gets tested for malaria at a clinic along the Thai-Cambodian border in 2010. Three strains of drug-resistant malaria have emerged from this region over the past 50 years. Paula Bronstein/Getty Images hide caption

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Signs of tuberculosis have been found in ancient Egyptian mummies, such as this one in London's British Museum. Klafubra/Wikimedia.org hide caption

itoggle caption Klafubra/Wikimedia.org

Percentage of deaths each year due to neonatal disorders around the globe. Courtesy of the Institute for Health Metrics and Evaluation hide caption

itoggle caption Courtesy of the Institute for Health Metrics and Evaluation

Latinos and African-Americans are more active on social media. Could that help promote HIV testing among minorities? Brendan Smialowski/Getty Images hide caption

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In early August, Israel launched a mass campaign to vaccinate children against polio, including this little girl at a clinic in Rahat. David Buimovitch/AFP/Getty Images hide caption

itoggle caption David Buimovitch/AFP/Getty Images

So cute, but not cuddly. The Egyptian tomb bat, Taphozous perforatus, is a likely carrier of the Middle East respiratory syndrome virus, or MERS. Courtesy of Jonathan H. Epstein/EcoHealth Alliance hide caption

itoggle caption Courtesy of Jonathan H. Epstein/EcoHealth Alliance