Better than Egyptian cotton: This electrically spun fabric contains anti-HIV drugs and dissolves rapidly when it gets wet. Courtesy of University of Washington hide caption

itoggle caption Courtesy of University of Washington

An outbreak of bird flu in India in 2008 prompted authorities to temporarily ban the sale of poultry. Diptendu Dutta/AFP/Getty Images hide caption

itoggle caption Diptendu Dutta/AFP/Getty Images

The usual suspect: Bats harbor dozens of deadly viruses, such as rabies and influenza. Several studies suggest that bats may also carry Ebola. Tyler Hicks/Getty Images hide caption

itoggle caption Tyler Hicks/Getty Images

Yonta, 6, rests with her sister Montra, 3, and brother Leakhena, 4 months, under a mosquito net in the Pailin province of Cambodia — an epicenter of drug-resistant malaria. Paula Bronstein/Getty Images hide caption

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When Sule Koroma's sister Saudatu died of Ebola, his house in Freetown was put under a 21-day quarantine. The government sent two policeman to guard the house. Tommy Trenchard for NPR hide caption

itoggle caption Tommy Trenchard for NPR

Dr. Kent Brantly, of Fort Worth, Texas, was treating Ebola patients in Monrovia, Liberia, when he himself became infected with the virus. Courtesy of Samaritan's Purse hide caption

itoggle caption Courtesy of Samaritan's Purse

A health worker vaccinates a child during a polio campaign in Bannu, Pakistan, June 25. The Taliban threaten to kill vaccinators and parents who immunize their kids. A Majeed/AFP/Getty Images hide caption

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Red Cross volunteers prepare to bury the body of an Ebola victim in Pendembu, Sierra Leone, early this month. Tommy Trenchard for NPR hide caption

itoggle caption Tommy Trenchard for NPR

Usman (right), 7 months, and Abdullah (left), 18 months, are held by their mothers while they wait to receive the polio vaccine at the Jalozai refugee camp near Peshawar, Pakistan. Daniel Berehulak/Getty Images hide caption

itoggle caption Daniel Berehulak/Getty Images

During nationwide polio campaigns, hundreds of thousands of health workers go door to door, giving children two drops of the polio vaccine. Anadolu Agency/Getty Images hide caption

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Medical workers treat Ebola patients at the Eternal Love Winning Africa hospital in Monrovia, Liberia. Three workers at the hospital, including Dr. Kent Brantly (left), have tested positive for Ebola. Courtesy of Samaritan's Purse hide caption

itoggle caption Courtesy of Samaritan's Purse