There's a surveillance program tracking disease threats in the U.S. right now. The Centers for Disease Control and Prevention (CDC) has teams in major airports across the country, collecting samples from international travelers.

One Florida woman reached out to CBS News Miami after she encountered one of these programs at Miami International Airport.

Airport encounter

Johanna did not wish to share her full identity, but said she flew into MIA in February from Bogota, Colombia, and claimed she was greeted with an unexpected request.

"They pulled me and my mother aside and they say, you know, kind of like, 'Come over here,' and put those samples in our hands, kind of like this, and then you need to get tested," she said.

Johanna claimed that after going through customs, three people wearing scrubs approached her and asked her for a swab sample.

"The guy opens the swab, and he's like, 'you need to swab yourself,'" she explained. "I said, 'Is this mandatory?' And the man said, 'yeah.'"

Johanna said she was hesitant but complied. She added that what happened next was also unsettling.

"The man opened two swabs and made us swab twice, and both times we had to put our swab in a container with other swabs in there," she told CBS News Miami.

Johanna said she walked away feeling confused and upset.

Operating since the pandemic

After sharing her story, CBS News Miami reached out to MIA before being referred to the CDC.

The agency said the nasal swab is part of the agency's Traveler-based Genomic Surveillance program ( TGS ), which launched in 2021 in the wake of the COVID-19 pandemic . The CDC, along with local private partners, operates the program in at least six major airports across the country. Miami was added last spring.

The CDC told CBS News Miami the samples help it detect the flu, RSV and new COVID variants, and that about 800 travelers participate in the health check every week at MIA.

In email correspondence with the CDC, a spokesperson emphasized that participation is completely voluntary and anonymous, and they do not collect personal information.

The first swab is pooled with other swabs of travelers, and they do that to maximize testing resources. The second swab is stored in case the first pool tests positive, and they need to do additional testing.

Raising awareness

The details of the program are all pieces of information Johanna said she wished she knew before landing in Miami last month.

"If this is a program, they should just stand there and literally just wait for people to approach them or tell them, like this is just a voluntary sample if you would like to give us one," she said.

"We are working with our vendor to review training protocols and scripts that we have in both languages to avoid any ambiguity regarding the voluntary nature of the program."