Disease outbreaks

Anti-vaccination protestors Christie Nadzieja, front, Bob Runnells, back left, and Katie Bauer, back right, all of Vancouver, Washington, stand up and turn their backs on Gov. Jay Inslee on Friday, May 10, 2019, in Vancouver, Wash., as he signs a bill into law that eliminates personal belief and philosophical exemptions for the measles mumps and rubella vaccine for children who wish to attend school or day care. (AP Photo/Gillian Flaccus)

FILE - In this Sunday, Sept. 9, 2018 file photo, a health worker feeds a boy suspected of having the Ebola virus at an Ebola treatment centre in Beni, Eastern Congo. The World Health Organization says Ebola deaths in Congo's latest outbreak are expected to exceed 1,000 later on Friday, May 3, 2019. WHO's emergencies chief made the announcement at a news conference in Geneva. The Ebola outbreak that was declared in eastern Congo in August is already the second deadliest outbreak in history, and efforts to control it have been complicated by a volatile security situation and deep community mistrust. (AP Photo/Al-hadji Kudra Maliro, File)

The Cal State University, Los Angeles Student Union building is seen in Los Angeles Thursday, April 25, 2019. Hundreds of students and staff at two Los Angeles universities, including Cal State University, have been placed under quarantine because they may have been exposed to measles and either have not been vaccinated or cannot verify that they are immune, officials said Thursday. (AP Photo/Damian Dovarganes)

This 2004 electron microscope image made available by the Centers for Disease Control and Prevention shows Gram-negative Campylobacter fetus bacteria. As of April 2019, recent illnesses tied to raw turkey, ground beef, cut melon and romaine lettuce suggest, U.S. food poisoning cases don’t appear to be going away anytime soon. Salmonella and campylobacter are allowed in raw poultry sold in supermarkets, noted Tony Corbo of Food and Water Watch, an advocacy group that supports stricter food safety regulations. It’s why health experts advise people to properly handle and cook poultry. (Janice Haney Carr/CDC via AP)

FILE - This Feb. 6, 2015, file photo shows a measles, mumps and rubella vaccine on a countertop at a pediatrics clinic in Greenbrae, Calif. Hundreds of opponents of mandatory vaccines are opposing a California proposal to give state public health officials instead of local doctors the power to decide which children can skip their shots before attending school. They plan to pack the first legislative hearing Wednesday, April 24, 2019 on a bill that proponents say would stem bogus exemptions granted in many cases by doctors who are paid to excuse students from vaccinations. Supporters say pockets of unvaccinated students help to spread measles. (AP Photo/Eric Risberg, File)

FILE - In this Jan. 30, 2019 file photo signs posted at The Vancouver Clinic in Vancouver, Wash., warn patients and visitors of a measles outbreak. Washington state lawmakers voted Tuesday, April 23, 2019, to remove parents' ability to claim a personal or philosophical exemption from vaccinating their children for measles, although medical and religious exemptions will remain. (AP Photo/Gillian Flaccus, File)

FILE - This March 27, 2019 file photo shows a sign explaining the local state of emergency because of a measles outbreak at the Rockland County Health Department in Pomona, N.Y. Outbreaks in New York state continue to drive up U.S. measles cases, which remain on pace to set a record for most illnesses in 25 years. (AP Photo/Seth Wenig, File)