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EL PASO, TX — For decades, Chagas disease was largely categorized by the American medical establishment as a “tropical disease,” a concern for those traveling deep into Central or South America. However, new research from the University of Texas at El Paso (UTEP) is shifting that narrative, revealing that a “silent” and potentially deadly parasite is firmly established—and potentially increasing—along the U.S.-Mexico border.
A research team led by Rosa Maldonado, Ph.D., a prominent expert in parasitic infections at UTEP, recently uncovered a startling infection rate among local insect populations. In a study published in Epidemiology and Infection, researchers found that 22 out of 26 kissing bugs collected near the El Paso-Las Cruces border region tested positive for Trypanosoma cruzi (T. cruzi), the parasite responsible for Chagas disease.
With an infection rate hovering near 85% in this small sample, the findings underscore a growing public health challenge: a disease that can hide in the human body for decades, damaging the heart without causing a single early symptom.
The “Kissing Bug” and Its Messy Transmission
The culprit behind the spread is the triatomine bug, colloquially known as the “kissing bug” because it tends to bite humans near the mouth or eyes while they sleep. But unlike mosquitoes that transmit disease through a bite, the kissing bug’s method is far more indirect.
“Kissing bugs act as a vector,” explains Dr. Maldonado. “They feed on blood at night, and after the meal, the insect defecates near the bite wound.” The parasite, T. cruzi, lives in the insect’s hindgut. When a person instinctively rubs the bite or pushes the feces into the wound, or into their eyes or mouth, the parasite enters the bloodstream.
From April 2024 to March 2025, UTEP field teams monitored the boundary where desert wildlife meets residential neighborhoods. Using light traps, they captured adult Triatoma rubida—a specific species of kissing bug—under porches, near woodpiles, and in popular hiking spots like Franklin Mountains State Park.
A Decade of Silence: The Chronic Threat
What makes Chagas disease particularly insidious is its “silent” phase. According to the Centers for Disease Control and Prevention (CDC), an estimated 8 million people are infected worldwide, but most are unaware of it.
After an initial infection—which might cause mild swelling or fever that mimics a common flu—the parasite enters a chronic phase. It slips into the muscle cells of the heart and digestive tract, where it can hide for 10 to 20 years.
“The parasite hides and slowly scars the tissue,” says Dr. Anthony Verity, a cardiologist not involved in the study. “By the time a patient presents with heart palpitations, shortness of breath, or an enlarged esophagus, the damage is often irreversible. We are essentially playing catch-up with a decades-old infection.”
Health officials estimate that approximately 30% of those chronically infected will eventually develop life-threatening cardiac complications, including:
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Heart failure
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Cardiac arrest (due to electrical rhythm disruptions)
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Dilated cardiomyopathy (an enlarged, weakened heart)
Shifting Numbers: Is the Risk Rising?
The recent UTEP findings suggest a potential uptick in local risk. In a similar survey conducted by Maldonado’s group in 2021, the infection rate in collected bugs was 63.3%. The jump to over 84% in this latest surveillance period—though based on a smaller sample size—has raised eyebrows.
“T. cruzi infections appear to be increasing,” Dr. Maldonado noted, though she cautioned that wider, multi-season trapping is necessary to confirm if this trend holds across the entire Southwest.
The risk isn’t limited to humans. Wildlife such as raccoons, opossums, and woodrats act as “reservoirs,” keeping the parasite circulating in the environment. Domestic pets, particularly dogs, are also highly susceptible. Veterinarians in the Southwest increasingly recommend that dogs sleep indoors to avoid nocturnal contact with the bugs.
The Diagnostic Gap
Despite the presence of the parasite in the U.S., Chagas disease remains a “neglected” condition in the American healthcare system. Because the long-term symptoms mimic other forms of heart disease, many clinicians do not think to test for it.
Standard diagnosis requires a blood test to detect antibodies—the body’s immune response to the parasite—rather than the parasite itself, which is often tucked away in tissue.
“Without routine screening and mandatory reporting, our health systems are essentially flying blind,” says Dr. Maldonado. To bridge this gap, her team plans to offer blood screening to El Paso residents in the coming year, focusing on those who live in high-risk areas where bugs and wildlife overlap.
Protecting Your Home and Family
While the presence of infected bugs is concerning, health officials emphasize that simple environmental changes can drastically reduce the risk of transmission. The bugs are attracted to the heat and carbon dioxide emitted by sleeping hosts, but they prefer to hide in dark, cool crevices during the day.
Practical Prevention Steps:
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Seal the Envelope: Use weather stripping and caulk to seal cracks around windows, doors, and foundations.
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Screen Integrity: Ensure window and door screens are tight-fitting and free of holes.
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Clear the Perimeter: Move woodpiles, rock heaps, and yard debris at least 20 feet away from the house.
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Lighting Adjustments: Dim outdoor porch lights or switch to yellow “bug bulbs” that are less attractive to nocturnal insects.
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Pet Safety: Keep dogs and cats indoors at night, especially during the peak summer months.
What to do if you find a bug:
If you find a suspected kissing bug, do not squash it with your bare hands, as this could expose you to the parasite. Instead, trap it in a jar (using gloves or a tool) and contact your local health department or university extension office for identification.
Looking Ahead
The findings from El Paso are a reminder that the borders of infectious diseases are fluid. As urbanization pushes further into desert habitats, the “boundary” between humans and vectors disappears.
“This is about awareness, not alarmism,” says Dr. Maldonado. By pairing bug surveillance with public education and earlier medical testing, the goal is to catch the “silent traveler” before it has the chance to cause permanent damage.
Medical Disclaimer
This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.
References and Sources
Peer-Reviewed Study:
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Epidemiology and Infection (2025). “Surveillance of Triatoma rubida and Trypanosoma cruzi prevalence in the El Paso-Las Cruces border region.” Maldonado, R., et al.
