Researchers at North Carolina State University report that heavier cockroach infestations in Raleigh apartment homes were associated with higher concentrations of cockroach allergens and bacterial endotoxins in dust and air. Units where extermination eliminated roaches saw steep declines in both, underscoring the health benefits of effective pest control.
A North Carolina State University team found a clear relationship between the size of cockroach infestations and the amount of cockroach allergens and bacterial endotoxins measured indoors. Homes where professional extermination eliminated cockroaches had marked drops in both pollutants, the researchers said. (news.ncsu.edu)
Endotoxins are fragments of bacterial cell walls released when bacteria die; cockroaches’ broad diets support diverse gut microbiomes that shed endotoxins in feces. In this study, a large share of the endotoxins detected in household dust was associated with cockroach feces. (news.ncsu.edu)
The field work took place in multi‑unit apartment complexes in Raleigh, North Carolina. Researchers collected baseline samples of both settled and airborne dust, then compared infested apartments assigned to either no treatment or professional extermination with a control group of non‑infested homes. Follow‑up sampling occurred at three and six months. (news.ncsu.edu)
Untreated homes maintained high allergen and endotoxin levels across time points, while most exterminated units were cleared of cockroaches and showed substantial declines in both measures. Female cockroaches excreted about twice the endotoxin of males, and kitchens generally had higher endotoxin concentrations than bedrooms. (news.ncsu.edu)
“Endotoxins are important to human health, as inhalation of these components has been shown to provoke allergic responses,” said Coby Schal, the Blanton J. Whitmire Distinguished Professor of Entomology at NC State and a co‑corresponding author. He added that small reductions in roach numbers do not meaningfully lower allergen levels, whereas eliminating cockroaches sharply reduces both allergens and endotoxins. (news.ncsu.edu)
Co‑corresponding author Madhavi Kakumanu said that “female cockroaches eat more than males,” which helps explain their higher endotoxin output, and noted that allergens and endotoxins can also be airborne. (news.ncsu.edu)
The team plans to examine how cockroach allergens and endotoxins interact in animal models of asthma, including mice. The research appears in The Journal of Allergy and Clinical Immunology: Global (DOI: 10.1016/j.jacig.2025.100571). (news.ncsu.edu)
