A new coronavirus looks a lot like its cousin SARS under the microscope, but it appears they're quite different when it comes to contagiousness. NIAID/RML hide caption

itoggle caption NIAID/RML

Health officials around the world are on constant lookout for the deadly bird flu. Here a worker collects chickens on a farm in Kathamndu, Nepal, where the virus was suspected of infecting poultry last October. Prakas Mathema/AFP/Getty Images hide caption

itoggle caption Prakas Mathema/AFP/Getty Images

Coronaviruses have a characteristic crown of tentacles when viewed under the electron microscope. BSIP/UIG via Getty Images hide caption

itoggle caption BSIP/UIG via Getty Images

Virologists discovered the new coronavirus after it killed a Saudi Arabian man last summer. Elizabeth R. Fischer/Rocky Mountain Labs/NIAID/NIH hide caption

itoggle caption Elizabeth R. Fischer/Rocky Mountain Labs/NIAID/NIH

An artist on Rio de Janeiro's Copacabana beach puts the final touches on a sand sculpture of the kissing bug, which spreads Chagas' disease. The sculpture was part of an event in 2009 commemorating the 100th anniversary of the discovery of the disease. Vanderlei Almeida/AFP/Getty Images hide caption

itoggle caption Vanderlei Almeida/AFP/Getty Images

Health workers in Nepal culled chickens and destroyed eggs following an outbreak of bird flu in Kathmandu in October 2012. Prakash Mathema/AFP/Getty Images hide caption

itoggle caption Prakash Mathema/AFP/Getty Images

A boy with multiple Guinea worms sits outside a containment center in northern Ghana, February 2007. Wes Pope/Chicago Tribune/MCT /Landov hide caption

itoggle caption Wes Pope/Chicago Tribune/MCT /Landov

When flu viruses (in red) accumulate an escape protein too quickly, they exit the cell nucleus (in blue) before they've made enough viral copies to spread the infection. Benjamin tenOever hide caption

itoggle caption Benjamin tenOever

A copper engraving from 1656 shows a plague doctor in Rome wearing a protective suit and a mask. Artwork by Paul Furst /Wikimedia.org hide caption

itoggle caption Artwork by Paul Furst /Wikimedia.org

Microbiologist Emma Allen-Vercoe invented the Robogut, a mechanical device that mimics conditions in the human colon. Courtesy of thestar.com hide caption

itoggle caption Courtesy of thestar.com

Registered nurse Michelle Newbury and physician assistant Scott Fillman see patients Thursday in a tent set up for people with flu symptoms, just outside the emergency entrance at the Lehigh Valley Hospital in Allentown, Pa. Matt Rourke/AP hide caption

itoggle caption Matt Rourke/AP

In the U.S., doctors no longer have the option of treating gonorrhea with a pill. Instead, they are advised to use an injectable antibiotic, which is still effective against the bacteria. iStockphoto.com hide caption

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