As a cyclosporiasis outbreak spreads across the country, Sen. Jon Ossoff wants to know why the Trump administration made it harder to track the parasite that causes diarrhea.

In a letter Thursday to Health Secretary Robert F. Kennedy Jr., the Georgia Democrat noted that last year, the Centers for Disease Control and Prevention changed a pathogen surveillance program so that monitoring cyclospora was no longer required.

“And now a cyclosporiasis outbreak sweeps the nation,” Ossoff told Kennedy. “Your foolish and self-indulgent demolition of critical public health programs puts Americans at risk.”

The program, FoodNet, is a health safety network run by the CDC, the Agriculture Department, the Food and Drug Administration, and 10 states, tracking infections caused by eight different pathogens.

Last July, the Trump administration made data collection optional at FoodNet sites for all of the pathogens except for Salmonella and E. coli — part of the administration’s much broader cutbacks to health and science infrastructure.

“Has the CDC’s FoodNet been restored to require tracking of Cyclospora cayetanensis? If not, why?” Ossoff asked in his letter. “Why did you terminate tracking of Cyclospora cayetanensis in the first place?”

HHS, which includes the CDC, did not immediately respond to a request for comment Monday on the decision to downgrade cyclosporiasis monitoring. The CDC says on its website that dropping the reporting requirements made sense because “other surveillance systems monitor for infection with FoodNet pathogens.”

“Changes to the reporting requirements and associated activities allow FoodNet staff to prioritize core activities, while maintaining both the infrastructure and quality FoodNet represents,” the agency claims.

The cuts were made with no public announcement at the time, as NBC News reported last summer. “A lot of the work that I and many, many, many, many other people have put into improving food safety over the past 20 or 30 years is just going away,” one food safety expert told the outlet.

There have been thousands of confirmed or likely cyclosporiasis cases in dozens of states in recent weeks. The parasite causes explosive diarrhea that can last for weeks.

Robert B. Shpiner, a clinical professor of medicine at the David Geffen School of Medicine at UCLA, wrote in a Guardian opinion piece last week that the looser monitoring at FoodNet made it easier for the federal government to miss the outbreak.

The Trump administration’s change “did not contaminate anyone’s lettuce,” he wrote, but it weakened a system designed to alert us that “something unusual is happening.”

“That is the capacity the CDC downgraded, and the consequence is on the record,” he added.