As athletes and millions of fans gear up for the FIFA World Cup starting next week, global health officials are preparing for a high-stakes challenge of their own: protecting against infectious diseases.
For the first time, the tournament will span 16 host cities across three countries — the United States, Canada and Mexico — and feature 48 teams, making it the largest World Cup in history. The event also comes amid an Ebola outbreak in Congo and Uganda that the World Health Organization has designated a "public health emergency of international concern."
Despite those worries, the risk of widespread Ebola transmission during the tournament is low, infectious disease experts told CNBC. Public health departments, hospitals and other partners are also well equipped to respond to a range of potential threats — even after sweeping cuts to critical federal agencies and the U.S. exiting from the WHO under the Trump administration.
"Ebola and hantavirus, I worry about a lot less," Dr. Shruti Gohil, the associate medical director for University of California, Irvine Health Epidemiology and Infection Prevention, said in an interview. "The overall likelihood of risk is not nonzero, but it's low, very low, because it is not easy to transmit person to person."
Instead, experts say more contagious threats could pose greater challenges during the tournament and other large events this summer, particularly because international visitors could move through multiple venues and cities in a matter of days.
Those threats include measles — one of the world's most contagious diseases — as well as respiratory viruses such as Covid-19 and influenza. The concern comes after the U.S. recorded its highest number of measles cases in decades last year, driven in part by growing vaccine hesitancy and declining immunization rates.
Some experts also pointed to arboviruses spread by infected insects, such as dengue, while others highlighted heat-related and foodborne illnesses as notable risks beyond infectious diseases.
Preparing for the World Cup has involved scaling up existing programs, such as wastewater monitoring, and adding new tools to track infectious disease threats. Those systems will face their first major test when the tournament kicks off on June 11, but public health officials say they are ready to take on the challenge.
"Public health prides itself in being the invisible shield, but I don't want that to get lost in the actual Herculean effort it takes to have an operational invisible shield, so that people can enjoy events like the World Cup and feel safe and secure in their public health when they're here," said Dr. Theresa Tran, director for the Houston Health Department.
"That's a system that I'm extraordinarily proud about … we are absolutely working so hard every single day in preparation for things like this," said Tran, who is overseeing the response in a host city.
Ebola does not spread as easily as Covid and other respiratory diseases, making it less of a threat during the World Cup despite the growing outbreak, experts said.
Global health authorities have confirmed more than 260 cases and are investigating 1,100 more possible infections in Congo and Uganda, according to the WHO. The current strain of Ebola, the Bundibugyo virus, is an often fatal form of the disease with no approved treatment or vaccine.
But there were no cases of Ebola in the U.S. as of Wednesday. Virus transmission requires direct, close contact with the bodily fluids or blood of someone who is already showing symptoms, said Dr. Amesh Adalja, adjunct assistant professor at the Johns Hopkins Bloomberg School of Public Health, in an interview. Patients with Ebola are "going to be very sick" and will likely stay at home or in the hospital rather than attend large events with other people, he added.
"It's not a respiratory virus; it's not something that thrives in crowds that don't have exposure to blood and body fluids, so I don't think that it poses an objective threat to the World Cup," Adalja said.
Still, federal and local public health officials are gearing up to respond to Ebola risks.
The Centers for Disease Control and Prevention has implemented enhanced entry measures for travelers from countries linked to the outbreak. Anyone arriving in the U.S. after spending time in Congo, Uganda or South Sudan within the previous 21 days is required to enter through designated airports in Atlanta, Houston, New York or the Washington area, where they will undergo public health screening.
During those screenings, CDC staff will survey individuals about their travel history and symptoms, check their temperatures and collect contact information for follow-ups by state and local public authorities if needed, the agency's website says. Individuals are also monitored for Ebola's full incubation period of 21 days, not only the day they arrive in the U.S., UCI's Gohil said.
The screening protocol extends beyond the airport. Local health departments are notified when travelers from affected regions arrive in their jurisdictions, enabling officials to monitor them for signs of illness, said Dr. Marvia Jones, director of the health department for Kansas City, a host city.
In Dallas County, Texas, where World Cup games will also be played, the health department has coordinated with emergency responders and local hospitals to ensure any traveler who develops Ebola symptoms can be safely transported and treated, county health Director Dr. Phil Huang told CNBC. The plans include identifying which facilities would receive patients, preparing those places for infection-control protocols and arranging specialized transportation if needed.
Huang said the county also held a session to educate local healthcare providers on the lessons learned from Dallas' 2014 Ebola case, including the importance of obtaining travel histories, recognizing symptoms and following established procedures for patient transport, isolation, contact tracing and the use of personal protective equipment.
Ebola "is definitely top of mind as a heavy thing with our history," Huang said.
In a statement to CNBC, FIFA said it is aware and monitoring the Ebola outbreak and continues to work with all three host countries' governments to "ensure a safe and secure tournament." FIFA is also informing ticket holders residing in Congo, South Sudan and Uganda of travel considerations ahead of the event.
Measles is "our biggest concern" in terms of infectious diseases at the World Cup since it is one of the most contagious viruses, said James Garrow, communications director for Philadelphia's Department of Public Health.
"We're seeing outbreaks throughout the U.S. and overseas, and when you have a disease that's as infectious as this, people just have to be in the same plane for an hour or two and all of a sudden you have an outbreak that's transferred to somewhere else," Garrow told CNBC.
Philadelphia health officials have focused on ensuring healthcare providers can quickly identify measles cases, share information and coordinate response efforts as the city prepares to host matches, he said. But international visitors pose a particular challenge because they often travel to numerous locations in a short period of time, increasing the number of potential exposures to the virus compared to a local.
The U.S. had more measles cases in 2025 than in any other year since 1991, with more than 2,100 confirmed cases. Cases were reported in 45 jurisdictions in 2025, and there were 48 outbreaks, compared with 16 the previous year, according to the CDC.
The U.S. eliminated measles in 2000, but cases have risen as misinformation spreads and vaccination rates decline. About 93% of confirmed measles cases last year were among people who were unvaccinated or whose vaccination status was unknown, CDC data shows.
Besides measles, Houston's Tran said she's concerned about other diseases at risk of higher spread as vaccination rates drop in the U.S., such as Covid and the flu.
"The transmissibility being airborne makes them so much more likely to cause a public health threat than Ebola," she said.
But Houston, Tran said, has professional epidemiologists who are monitoring and contract-tracing individuals anytime there is a vaccine-preventable disease that could become an outbreak.
Norovirus, food-borne and heat-related illnesses as well as sexually transmitted infectious could also pose challenges during the tournament, some public health officials told CNBC.
But public health departments have been working to ensure that food vendors at the World Cup and related gatherings have the proper permits to sell to the public, said Dr. Monika Roy, the deputy health officer and infectious disease and response branch director for Santa Clara County, California. The county outside of San Francisco will also host matches.
In addition to keeping an eye on permitting, Houston has teams of registered sanitarians ready to investigate any foodborne illnesses, and it has prepared public health campaigns related to heat-related illness and prevention given the high humidity in the city.
This year's World Cup brings "added layers of challenges," and not only because of the scale of the event, said Dr. Rebecca Katz, who leads Georgetown University's Center for Global Health Science and Security. She said the tournament comes after resource cuts to public health and the U.S. withdrawal from the WHO earlier this year, which has "strained" international mechanisms for disease sharing.
Trump cut roughly 10% of the CDC's workforce in early 2025, leaving fewer epidemiologists and scientific staff to do boots-on-the-ground work or coordinate responses across governments. There is currently no permanent CDC director or U.S. surgeon general, both positions that play a critical role in responding to disease threats.
Despite the cuts, the CDC said it is "actively engaged in World Cup preparedness as part of the federal coordination structure led by the White House FIFA World Cup 2026 Task Force" and is engaging with public health departments in host cities, other federal agencies and partner organizations. The CDC has also developed a World Cup data dashboard, which is in final development, to give state and local health departments greater visibility into disease trends across jurisdictions, an agency spokesperson said in a statement.
Still, "there have been cuts to public health at all levels and the folks who are in those jobs are working really, really hard, often with a smaller budget and less personnel, so there's an opportunity for the rest of the community to help support that" and "try to jump in and fill some of those information gaps," Katz said.
That's one reason why Katz in May launched the Health Security Operations Center, a hub for monitoring potential infectious disease threats that will distribute daily situation reports starting Thursday to hundreds of state and local health officials, federal agencies, tournament organizers and hospital emergency managers, among others. It's part of the National Center for Health Security and Resilience, a joint effort between Georgetown University and MedStar Health.
Among the center's efforts is participating in daily stand-up calls hosted by the Pan American Health Organization, a regional office of the WHO, and sharing that information directly with local, state and federal jurisdictions, Katz said. PAHO is coordinating data between Mexico and Canada as well, she noted.
At the local level, health departments are ramping up their surveillance efforts.
Many World Cup host cities and counties are leaning on wastewater surveillance, a public health tool that gained prominence during the Covid pandemic. The approach enables officials to detect signs of disease spreading in a community through sewage samples, often before outbreaks are identified through traditional testing.
For example, Dallas is increasing its wastewater sample sites to cover nearly the entire county, Huang said. The county is also implementing metagenomic testing, which is broadly extracting and sequencing sewage samples to identify every bacteria, virus and fungus rather than a specific one, he added.
Huang said Dallas is also enhancing its mosquito surveillance by monitoring not only for West Nile virus, which is endemic in the region, but also diseases such as dengue, chikungunya and Zika.
Meanwhile, Philadelphia is deploying a new mobile lab that can test samples on site, speeding up the detection of potential health threats and reducing the need to send specimens to specialized labs elsewhere in the state or country, Garrow said. He noted that the lab, which launched in June, aims to boost testing capacity and reach areas less centrally located.
Dr. Margaret Aldrich, a pediatric epidemiologist at NYU Langone, said she believes in the U.S. "we're actually better prepared, honestly, than we ever have been for high-consequence infectious diseases."
"There's a very robust system in the United States," Aldrich said. "The departments of health are really continuing to maintain that hard work and ensuring that, as we always say, if we're doing our job, you don't see it."
