The 2026 World Cup is here, and so are the germs. This virus is experts’ No. 1 concern

While millions of soccer fans cheer or groan over World Cup matches spanning North America, health officials will be on high alert for germs.A heat wave may be the most obvious health threat. But infectious diseases can spread in a crowd, and experts are set to scrutinize wastewater, hospital visits, even social media for any signs that an outbreak might be brewing.Measles, one of the most contagious diseases, is among the top concerns, sparking a warning this week from the Pan American Health Organization, PAHO. With a nearly six-week stretch of packed stadiums, bars and tourist sites in 16 cities, officials are on the lookout for a long list of infections, from the stomach bug norovirus to mosquito-borne dengue fever.“This is truly a marathon,” said Palak Raval-Nelson, Philadelphia’s health commissioner.The mass gatherings come at a tense moment for budget-strapped health agencies in the U.S. The Centers for Disease Control and Prevention, hit hard by Trump administration staffing cuts, already was grappling with a growing Ebola outbreak in central Africa and a cruise ship hantavirus outbreak. While CDC officials have advised state and local health departments behind the scenes, its expected World Cup disease surveillance dashboard still was “in final development” days before games began, according to the Department of Health and Human Services.“Our public health professionals are pretty stretched,” said global health specialist Rebecca Katz of Georgetown University, who is leading an unusual new hub to help.At the Health Security Operations Center, a joint effort between Georgetown and MedStar Health, workers are analyzing data from around the country so they can alert health authorities, even emergency rooms, to any early signs of trouble. The center is issuing daily “situation reports” about disease trends around World Cup host cities and team base camps to several hundred local and federal public health gro