UofL researchers say wastewater testing showed flu surge before outbreak in Louisville

LOUISVILLE, Ky. (WDRB) -- According to public health officials, the nation is seeing the worst flu season in 15 years.

According to the U.S. Centers for Disease Control and Prevention, at least 24 million Americans have been infected, resulting in 310,000 hospitalizations and at least 13,000 deaths.

The CDC said 43 states, including Kentucky and Indiana, reported high or very high flu activity last week.

In Louisville, the flu was found in the city's wastewater before last week's surge in cases.

The city's wastewater is tested at the Metropolitan Sewer District's five water treatment plants around the city.

Local health officials are hoping to use the data collected by wastewater testing to work together in the future to keep the community safe.

Experts said the testing shows a spike in flu and COVID cases in the wastewater, a direct correlation to what's being seen in the community.

"We know that they go together and we see them together all the time," said Dr. Ted Smith, director of the University of Louisville's Center for Healthy Air, Water and Soil.

Smith has been testing Louisville's wastewater for illness for about five years. What started out as testing for COVID-19 during the pandemic has now turned into looking for flu patters as well.

"I hope we'll be using these tools to anticipate what may be coming," he said. "And maybe just a little more precautions, right?"

Smith said the testing showed high flu numbers a few weeks ago.

"We saw the surge in flu-A many weeks ago," he said. "We saw this tremendous growth."

Last week, several school districts across the area were forced to close or use remote learning days due to the amount of illness among students and staff.

The Louisville Department of Public Health and Wellness flu dashboard shows nearly 3,600 cases as of Feb. 8. It also shows there have been 12,578 flu cases reported in Jefferson County since Sept. 29, 2024.

However, Norton Healthcare's data shows nearly 6,000 positive flu cases across its system for that week.

A Baptist Health Louisville Emergency Services Executive Director Cheryl Freudenberger said ER visits are up 15% over last year, and a large percentage of that is for flu related illness with some COVID. There are currently 48 patients admitted for the flu, and 12 patients with COVID.

"Trust me, I look at the wastewater data and I make decisions about what I'm doing this weekend. I do," said Smith.

Smith said even though he and his team have been working on wastewater testing for the past five years, it's still a relatively new concept in the grand scheme of things, so they're still learning. He hopes to be able to work with the city's health department and local school districts to eventually be able to come up with a plan to mitigate the spread of illness.

"We've seen it in the rearview mirror, right, as kids and staff are sick, they're unable to run school," he said. "So we'd like to be able to get to a place where we can agree that maybe you cancel assemblies or maybe you increase the hand washing program or whatever it is when there's reason to believe we might want to try to get ahead of further growth."

In the meantime, Smith suggests continuing to wash your hands, cover you mouth with your arm when you cough or sneeze, and stay home when you're sick.

Doctors are also encouraging people to make sure they're up to date on their seasonal flu vaccinations. Data shows about 45% of American adults got their flu shot this winter. That leaves millions of people vulnerable, especially the elderly and those with underlying health conditions.

For more tips about helping to stop the spread of illnesses like the flu and COVID-19, click here.

To look at Louisville's flu data dashboard, click here. To look at national data from the CDC, click here.

To learn more about UofL's wastewater testing and how it works, click here.

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