Kissing Bugs and Chagas Disease
The bite of a kissing bug – also known as a cone-nose or assassin bug – is an unpleasant experience. The insect takes its blood meal at night, numbing the area where it feeds. The victim wakes to find a painful, itchy swelling. And the bug is long gone.
Bites, stings, thorns – it's all part of life in West Texas. But a kissing bug bite can have more serious consequences. The bug can transmit a potentially life-threatening disease called Chagas. A recent study suggests Chagas disease may be more widespread here than previously thought.
There are hundreds of species of kissing bugs, or triatoma, found from Argentina to the southern United States. In our area, the bugs are typically less than an inch long, with reddish-orange spots on the abdomen. The name kissing bug derives from the bug's habit of often planting its unwelcome “kiss” near its sleeping victim's mouth. The bugs can transmit Trypanosoma cruzi – the parasite that causes Chagas disease.
Dr. Rosa Maldonado is a molecular parasitologist at the University of Texas at El Paso. She's spent 25 years studying Chagas. First, in her native Brazil.
She said the cone-nose swells as it sucks blood. To relieve the pressure, many species of kissing bugs defecate as they feed.
This is when the parasite makes its move.
“When the kissing bug bites, it defecates at the same time, and in the feces of the kissing bugs is where the parasites are,” Maldonado said. “When you scratch, the parasite is able to enter the body, and then infect our cells – any cell. It's really promiscuous, the parasite.”
The initial symptoms of Chagas are flu-like – including fever and headaches. But over decades, the symptoms can become serious.
The parasite proliferates within the cells of its human host. It bursts and destroys those cells. Ultimately, the build-up of dead cells can enlarge the colon or esophagus or cause heart failure.
In Latin America, more than 11 million people are chronically infected, and the disease is believed to kill as many as 50,000 people a year.
In 2013, Maldonado launched a study on kissing bugs and Chagas at UTEP's Indio Ranch Research Station, about 20 miles south of Van Horn.
Of 39 bugs captured at the site, Maldonado found that 24 carried the T. cruzi parasite. The figure was far higher than she expected.
“So I thought that we were going to find some positives, around maybe 40 percent,” she said. “But when I saw 61 percent – it was, Oh, my God! This is huge – it's a lot.”
The findings suggest that Chagas may be more prevalent here than previously thought. She said that Texas has a high rate of heart disease. So it's possible that Chagas is a factor. Rural residents are the most vulnerable.
Treatment exists, and research shows it can be effective even when the disease is acute. Maldonado herself is working on a vaccine. But she said that simple prevention is the best approach.
Maldonado recommends spraying for bugs and making sure that windows, doors and cracks are sealed. Kissing bugs are found in the nests of rats and mice. Eliminating those nests can reduce the chance of a bite.
The disease was discovered in 1909, by the Brazilian scientist Carlos Chagas. And Brazil and other Latin American countries have policies in place to prevent the spread of the disease.
But in the United States, Chagas is not well-known. Maldonado hopes she can change that.
“The reception of the paper has been a surprise, that so many people got interested,” Maldonado said. “Always when I talk about Chagas disease, it's like I talk about [some] extraterrestrial thing. I think that with this work, maybe people realize it is here, and everybody is at risk, and the best thing you can do is get informed – awareness is very important.”
Chagas has been a part of human life in the Americas for millenia. Mummies found in Texas and Peru – dating back thousands of years – tested positive for Chagas. And the disease will likely be with us for centuries to come. Maldonado said there's no reason to panic about Chagas. But understanding it is the first step to controlling its spread.