Goats and Soda

The scene after a mortar attack on the southern city of Taez. Ahmad Al-Basha/Getty Images hide caption

Nurses give the oral polio vaccine to a Syrian child in a refugee camp in Turkey. The oral polio vaccine used throughout most of the developing world contains a form of the virus that has been weakened in the laboratory. But it's still a live virus. Carsten Koall/Getty Images hide caption

A tuberculosis patient in a hospital for chest diseases in the Indian region of Kashmir. NurPhoto/Getty Images hide caption

Brazilian members of the United Nations Stabilization Mission In Haiti stand by a shelter in Les Cayes ahead of a visit by U.N. Secretary-General Ban Ki-moon on October 15, 2016. Hector Retamal/AFP/Getty Images hide caption

The black-legged tick, ixodes scapularis, can spread Lyme disease. Smith Collection/Gado/Getty Images hide caption

Dr. Thumbi Mwangi, an infectious disease epidemiologist from Kenya, at Howard Theatre in Washington, DC, on Nov. 29, 2016. In the U.S., Mwangi worked on a vaccine for cows that aimed to combat the same disease he saw the bovine battle in Kenya as a kid. Akash Ghai/for NPR hide caption

Kadija Shellu is now 7. She had not only Ebola, but malaria as well. Ashoka Mukpo for NPR hide caption

Fishermen in Papua New Guinea, living on their boats, wait for the tide to change before going out to fish. Tuberculosis is a major health threat in the Pacific Ocean nation. Jason South/The AGE/Fairfax Media via Getty Images hide caption

A family member holds twins Eloisa (left) and Eloa, both 8 months old and born with microcephaly, during a Christmas gathering. The mother of the twins, Raquel, who lives in Brazil, said she contracted Zika during her pregnancy. Mario Tama/Getty Images hide caption

Illustration by Xaver Xylophon Xaver Xylophon hide caption

They had the right idea: During the worldwide flu epidemic that began in 1918, women in this U.S. office wore cloth masks. Bettmann/Bettmann Archive hide caption