Researchers report rising rates of Chagas parasite in kissing bugs

Researchers at The University of Texas at El Paso have found unusually high levels of parasitic infection in the insects that transmit Chagas disease in the Borderlands. The bugs were collected near homes and natural areas along the U.S.-Mexico border, raising concerns about the potential for local transmission of the disease in the Southwestern U.S.

Chagas disease, caused by the parasite Trypanosoma cruzi – or T. cruzi – is primarily spread by blood-feeding insects known as kissing bugs. The debilitating illness affects approximately 6 million people worldwide; in its 'chronic' phase, it can persist in the affected individual for decades without symptoms, which can lead to severe heart and gastrointestinal complications.

"The infection prevalence in kissing bugs has risen significantly, from 63.3% in a study we conducted in 2021 to now 88.5%, indicating a marked upward trend. T. cruzi infections appear to be increasing," said Rosa Maldonado, Ph.D., a UTEP professor of biological sciences who led the study, published in the journal Epidemiology & Infection, in collaboration with Priscila S. G. Farani, Ph.D., assistant professor in UTEP's School of Pharmacy.

For the study, UTEP researchers collected kissing bugs from El Paso County, Texas, and southern New Mexico, including from yards, under garden furniture and firewood; Franklin Mountains State Park; the UTEP area; El Paso High School; and Canutillo.

Of the 26 kissing bugs collected, 22 – or 88.5% – were positive for T. cruzi. A similar study conducted in 2021 by the same team found that only 66% of kissing bugs collected in the region carried the parasite.

The results demonstrate that Chagas is an increasing public health issue for the Southwest, whereas the disease was primarily confined to Latin America in years prior, the team said.

Maldonado also shared a few practical preventative measures for the public:

• Homes should be sealed by closing cracks and gaps that may allow kissing bugs to enter.
• Pets can get Chagas, too, so it's important to keep them indoors when possible.
• Debris and woodpiles near houses should be removed, as these insects often take shelter under shaded structures.
• Installing insect screens on windows can help keep bugs out.
• Turn off outdoor lights at night; light can attract the bugs.

In the coming year the team plans to conduct a study with local El Pasoans to see if members of the public are already carrying the disease.