Since the first case on May 20, confirmed cases of Middle East respiratory syndrome, or MERS, have swelled to at least 30 in South Korea. Chung Sung-Jun/Getty Images hide caption

itoggle caption Chung Sung-Jun/Getty Images

A South Korean walks through a market in Seoul wearing a mask. South Korean President Park Geun-Hye scolded health officials over their "insufficient" response to an outbreak of the MERS virus. Ed Jones/AFP/Getty Images hide caption

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Carlo Ratti of MIT designed this "supermarket of the future" exhibit. If you move a hand close to a product, a digital display lights up, providing information on origin, nutritional value and carbon footprint. Courtesy of COOP Italia hide caption

itoggle caption Courtesy of COOP Italia

In this photo from 2014, passengers walk past the Middle East respiratory syndrome quarantine area at Manila's International Airport in the Phillipines. The virus is now raising public concern in South Korea. Aaron Favila/AP hide caption

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The man who died of Lassa fever flew from West Africa to New York's John F. Kennedy Airport. Spencer Platt/Getty Images hide caption

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Health workers collect the body of a cholera victim in Petionville, Haiti, February 2011. The cholera outbreak in Haiti began in October 2010. Nearly 9,000 people have died. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

A new smartphone app gives a close-up view of a patient's eye. Screengrab from video by Peek Vision, produced in collaboration with Sony Mobile. hide caption

itoggle caption Screengrab from video by Peek Vision, produced in collaboration with Sony Mobile.

Patients receive treatment at the Chest Disease Hospital in Srinagar, India. The country has one of the highest rates of drug-resistant tuberculosis in the world, in part because antibiotics for the disease are poorly regulated by the government. Dar Yasin/AP hide caption

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A single Lassa fever virus particle, stained to show surface spikes — they're yellow — that help the virus infect its host cells. London School of Hygiene & Tropical Medicine hide caption

itoggle caption London School of Hygiene & Tropical Medicine

How can women in rural Nigeria get the care they need? That's what Columbia University graduate students in public health asked residents of Kadawawa, Nigeria. Courtesy of Alastair Ager and Alissa Pires hide caption

itoggle caption Courtesy of Alastair Ager and Alissa Pires