Bats congregate in the Bat Cave in Queen Elizabeth National Park on August 24, 2018. Scientists placed GPS devices on some of the bats to determine flight patterns and how they transmit Marburg virus to humans. Approximately 50,000 bats dwell in the cave. Bonnie Jo Mount/The Washington Post via Getty Images hide caption
People line up for COVID-19 vaccinations last month in Hagerstown, Md. Each person vaccinated helps end the pandemic, epidemiologists say, and helps lower the rate of hospitalization and death from COVID-19. Chip Somodevilla/Getty Images hide caption
Dr. Scott Atlas is President Trump's new coronavirus adviser. His ideas are sometimes at odds with those of public health professionals. Chris O'Meara/AP hide caption
"We need to get out ahead of this and do everything we possibly can here in Massachusetts — through and in the aftermath of the surge," said Massachusetts Gov. Charlie Baker, in announcing his state's public health initiative April 3. Nicolaus Czarnecki/MediaNews Group/Boston Herald hide caption
Viral particles are colorized purple in this color-enhanced transmission electron micrograph from a COVID-19 patient in the United States. Computer modeling can help epidemiologists predict how and where the illness will move next. Hannah A Bullock and Azaibi Tamin/CDC/Science Source hide caption
Parts of the Cape Fear River near Fayetteville, N.C., are contaminated with a PFAS compound called GenX. The North Carolina Department of Health and Human Services is surveying residents in the area about their health. Mark Wilson/Getty Images hide caption
Smog fills Utah's Salt Lake Valley in January 2017. Winter weather in the area often traps air pollution that is bad for public health. George Frey/Getty Images hide caption
A needle exchange program at the Austin Community Outreach Center in Austin, Ind., is aimed at stopping spread of HIV. Darron Cummings/AP hide caption
In 1962, a local leader in the Eastern Highlands of Papua New Guinea asks Fore men to stop the sorcery that he believes is killing women and children. Courtesy Shirley Lindenbaum hide caption
Mosquitoes hover around South Korea's bronze medalist Ki Bo Bae during the medal ceremony for archery, held on Aug. 11 at the Rio Games. Jewel Samad/AFP/Getty Images hide caption
Secretary of State John Kerry and African Union Commission Chairperson Nkosazana Dlamini Zuma signed an agreement Monday to establish the first Centers for Disease Control and Prevention in Africa. The U.S. will provide technical advice and a few staff for the agency. Alex Wong/Getty Images hide caption
A hand-drawn map on the wall of a rural clinic shows health workers where a woman with Ebola may be hiding. Kelly McEvers/NPR hide caption
Hotspots show where the common cold is popping up across the U.S. via Sickweather hide caption
Children play in the West Point neighborhood of Monrovia last week. West Point has been hit hard by Ebola. So local leaders formed their own Ebola task force, which goes door to door looking for cases. John Moore/Getty Images hide caption
A woman on the L train in New York City last week covers her face, fearful because a doctor with Ebola rode the train days earlier. Epidemiologists say people on the subway were not at risk. Stephen Nessen/WNYC hide caption
A security man takes visitors' temperatures Wednesday at the Transcorp Hilton hotel in Abuja, Nigeria, about 400 miles north of Port Harcourt. Afolabi Sotunde/Reuters/Landov hide caption
Kenyan health officials take the temperatures of passengers arriving at the Nairobi airport on Thursday. Kenya has no reported cases of Ebola, but it's a transportation hub and so is on alert. Simon Maina/AFP/Getty Images hide caption
Average life expectancy around the world has ticked up over the past twenty years. Here it's shown for men in 2009. The extremes are in dark green and dark red, which represent 78 to 82 years old and less than 66 years old, respectively. Courtesy of the Institute for Health Metrics and Evaluation hide caption
Lack of control and high demands make work stressful. iStockphoto.com hide caption