bad sitting posture Lily Padula for NPR hide caption
Michaeleen Doucleff Michaeleen Doucleff is a reporter for NPR's Science Desk.
A colored scanning electron micrograph of a female Anopheles mosquito, a vector for the malaria parasite Plasmodium vivax. Dennis Kunkel/Science Source hide caption
A mother holds her newborn twins at a Sri Krishna Medical College and Hospital, a public health facility in India. Paula Bronstein/The Verbatim Agency/Getty Images hide caption
Gelmy, 9, and sister Alexa, 4, climbing trees in the backyard of their family home in the Yucatan Peninsula. Adriana Zehbrauskas for NPR hide caption
Maria de los Angeles Tun Burgos with daughters Angela, 12, and Gelmy, 9, in their family home in a Maya village in Yucatán, Mexico. Adriana Zehbrauskas for NPR hide caption
Patients are treated at an Army ward in Kansas during the influenza epidemic of 1918. About 675,000 Americans died of the flu known as "la grippe." NYPL/Science Source/Getty Images hide caption
The white, threadlike Guinea worm emerges from an infected foot. SPL/Science Source hide caption
Suspicious travel companions: Bacteria can survive for days on surfaces inside a plane. But that doesn't mean you have to take these critters home with you. Benjamin Arthur for NPR hide caption
A man bends with a beautiful hip hinge in Puerta Vallarta, Mexico. Courtesy of Jean Couch hide caption
Influenza covers its shell with two types of accessories: the H spike, blue, and the N spike, red. Here the flu particle is sliced open to show its genetic material. Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases hide caption