Cockroach Infestations and Indoor Air Quality: What Studies Reveal

Cockroaches may be common household pests, but new research shows they also play a major role in degrading indoor air quality.

A study by North Carolina State University, published in The Journal of Allergy and Clinical Immunology: Global, has found a strong link between cockroach infestations and elevated levels of bacterial endotoxins and allergens inside homes.

What are endotoxins?

Endotoxins are components of bacterial cell walls released when bacteria die. Because cockroaches feed on diverse materials, they carry a wide range of gut bacteria and shed large quantities of endotoxins through their droppings.

According to researchers, removing cockroaches through pest control significantly reduces both endotoxins and allergens.

Study findings

The study was conducted across multi-unit apartment complexes in Raleigh, North Carolina. Scientists measured the extent of cockroach infestations and the concentration of endotoxins and allergens in the homes.

Key findings include:

Infested homes had substantially higher levels of endotoxins.

Female cockroaches produced nearly twice as many endotoxins as males.

Kitchens had the highest endotoxin levels due to readily available food sources.

“Cockroaches are a significant source of both endotoxins and potent allergens,” the researchers said, warning that these exposures can be especially harmful to children with asthma.

Why it matters

Coby Schal, co-corresponding author and Distinguished Professor of Entomology at NC State, told Science Daily that endotoxins can trigger allergic reactions when inhaled. Past U.S. surveys have shown higher endotoxin levels in homes with signs of cockroach activity, particularly in low-income households.

The study also confirmed that allergens and endotoxins can become airborne. Homes where cockroaches were eliminated saw a significant drop in allergen levels, highlighting the importance of regular pest management. Schal added that future studies will examine how cockroach allergens and endotoxins interact in asthma models. “There exists the implication that asthma can be worse due to interactions between allergens and endotoxins,” he said.