In the heart of Iowa’s agricultural landscape, a new study is examining an invisible threat within rural homes. Kathryn Dalton, assistant professor of occupational and environmental health, is investigating how proximity to concentrated animal feeding operations (CAFOs) might increase the risk of exposure to antimicrobial-resistant genes—a finding that could reshape how we understand occupational health in farming communities.

Dalton’s research shows that homes located closer to CAFOs are more likely to harbor antimicrobial resistance (AMR) genes, including genes associated with multi-drug resistance.

“My work on antimicrobial resistance in Iowa farmers is still ongoing,” Dalton says. “But we already see that agricultural workers living closer to CAFOs have higher odds of having AMR genes present in their homes. That’s important because the home can be a reservoir for these genes, potentially leading to infections in both workers and their families.”

Studying the Resistome

Dalton’s interest in rural health is personal. She grew up in an agricultural community and worked as a veterinarian before shifting to public health. That path shaped her understanding of how animal husbandry practices might contribute to the presence of resistant genes in the environment. While previous studies have linked CAFOs to resistant pathogens in soil and water, Dalton’s approach is novel—she is examining the broader microbial community within homes, known as the resistome.

“I was surprised to find such a strong association between proximity to CAFOs and the presence of AMR genes in homes,” Dalton says. “Especially that we saw this pattern extending up to 10 kilometers away. That goes well beyond the 2- to 5-kilometer radius most previous studies have focused on.”

For Dalton, the implications go beyond academic discovery. The research raises practical concerns for the health and safety of agricultural families.

“If more AMR genes are found in homes near CAFOs, extending good biosecurity and hygiene practices to the home—like removing work clothes and shoes before entering, and enhanced cleaning—could help reduce exposure,” she explains.

Future Research Directions

However, Dalton says there is still a need for more information about how AMR genes are transmitted from CAFOs to homes, such as whether they are carried by workers or spread through the environment.

“We also lack understanding of how the presence of AMR genes in the home translates to actual risk of infection in people,” she says. “The causal link between environmental exposure of AMR genes and resistant infections in individuals is not clear cut, and this has altered how I communicate the risk to the public and helped to direct future research.”

Dalton is now expanding the study to explore infection rates and environmental transmission routes in rural communities. “If we can track other reservoirs of AMR genes and see a pattern in resistant infections,” she says, “we’ll be better equipped to design interventions that protect farmers and their families.”

This story appeared in the fall 2025 issue of Iowa Public Health Magazine