To Stop Chagas Disease, Biologists Go Bug Hunting

Originally published September 25, 2015

By Nadia M. Whitehead

UTEP News Service

Steven Galvan is an expert at catching kissing bugs.

Steven Galvan, a former UT Dallas undergraduate that conducted research for UTEP, caught 39 kissing bugs for a study that examined Chagas disease’s prevalence in Texas. Photo by J.R. Hernandez / UTEP News Service

At 19, the young biologist set out to a remote region of the Chihuahuan Desert in search of the reddish brown, inch-long insects, but he wasn’t doing it for fun. It was for science.

As part of The University of Texas at El Paso’s Chihuahuan Desert Biodiversity Research Experiences for Undergraduates (CD-REU) program, Galvan teamed up with Rosa Maldonado, D.Sc., a UTEP associate professor of biological sciences who specializes in the study of Chagas disease.

Kissing bugs are notorious for transmitting Chagas disease — a parasitic illness that can cause life-threatening health issues. Unlike mosquitoes that transmit malaria through the bite, the blood-sucking pests drop feces on the subject while filling up with blood. The feces, which can be contaminated with the parasite Trypanosoma cruzi (T. cruzi), often lands in the bite wound and from there penetrates the bloodstream and attacks the heart and gastrointestinal system.

Chagas disease was confined to South America for decades, but these days, researchers fear it’s spreading into the U.S. Climate change and warming temperatures may mean the insects are moving northward from their usual range in the south. But to confirm that hypothesis, researchers need to collect kissing bugs in the U.S. and then test them for the parasite.

That’s exactly what Galvan did back in the summer of 2013. The dedicated University of Texas at Dallas undergraduate who was interested in conducting research for UTEP spent six days in Texas’ Indio Mountains — an arid area about 100 miles north of the U.S.-Mexico border — searching for the creepy crawlers.

UTEP’s Indio Mountains Research Station, an entirely self-sustained laboratory and dorm, provided him with comfy room and board during his research stint in the secluded desert. Galvan was able to spend his days learning about other student projects in the area and then complete his own work at night.

“Kissing bugs come out as soon as the sun goes down,” Galvan explained. “And they’re attracted to light, so I would turn on the back porch lights to get their attention.”

Then he sat and waited, keeping his eyes peeled for critters. When one would crawl onto the porch, Galvan would move. He’d sneak up on the kissing bug, delicately snatch it up and then plop it into a jar of alcohol.

“The most important thing was to not let them bite me, in case they were carrying the parasite,” Galvan said. “But I learned how to pinch them between two fingers so that they weren’t in a position to hurt me.”

Galvan’s six night shifts paid off. He ended up catching a total of 39 kissing bugs, which were brought back to UTEP for dissection.

“I extracted their digestive tract, their intestines, which is where the parasite would be if they were carrying it,” Galvan explained. He then ran analyses on the content of the intestines to see if any tested positive for the parasite T. cruzi.

The results were surprising. Sixty percent of the bugs Galvan had caught had the parasite —meaning they could infect someone with Chagas disease.

“It was initially alarming because it shows that this disease is at our doorstep,” Galvan said. “At the same time, it was kind of exciting. We achieved what we set out to do, which was prove that the disease was present in the Chihuahuan Desert.”

Maldonado, who mentored Galvan throughout the project, was just as surprised, but glad they were able to collect such valuable data about the parasite’s presence in Texas.

“No study has been done in this region,” Maldonado said. “It’s important to know what’s going on in the area so that we can tell residents to be careful if they see these bugs.”

She also wants doctors to be conscious of the disease and encourages screening of patients for the disease when suspicion is raised.

“Doctors usually don’t consider Chagas disease when they diagnose patients, so they need to be aware of its prevalence here,” Maldonado said.

Maldonado warns that infection with the parasite can lead to serious health issues, so doctors need to be on guard. Thirty percent of patients develop life-threatening symptoms like heart rhythm abnormalities and difficult eating or passing stool. The disease also can lead to an enlarged esophagus, colon and heart, and even heart failure.

In July, both Galvan and Maldonado’s names were published in the journal Acta Tropica alongside a detailed report of their findings.

The two hope the paper brings more awareness to the often overlooked disease, which they call an emerging infectious disease in the U.S.