NATURE NOTES:
The Cone-Nose and Chagas Disease: West Texas Realities to Reckon With

For this episode, Nature Notes is teaming up with “West Texas Wonders” – a new reporting series where listeners ask questions and Marfa Public Radio finds answers.

This week, a question from Rachel Monroe of Marfa. Monroe was preparing recently for a Big Bend river trip. It was summer, and she thought she and her companion, a park ranger, could sleep in the open air, under the stars. But the ranger rejected that idea – emphatically. The borderlands, the ranger said, are home to a blood-sucking insect known as the cone-nose or kissing bug. And the insect can transmit a fatal disease.

“My impression was that they would bite you, and it was one of those situations where you would be okay, and then 10 years later you would get a terrible disease and you would die,” Monroe said. “I think you would die of a heart attack. I would just be curious to know – where in the region are they most likely to be? How much do we need to be careful?”

Though invariably unpleasant, a kissing bug bite is by no means a death sentence. But Monroe’s question can’t be dismissed. There’s growing evidence that the cone-nose-borne disease known as Chagas is a real concern in West Texas. We can, and should, take precautions.

It’s unlikable in the extreme, but its adaptations are impressive. The cone-nose is about an inch long, pear-shaped, dark brown, with red to white stripes on its abdomen. Operating at night, it detects CO2 from its sleeping target’s breath. Its saliva contains both an anesthetic, and an anticoagulant. The victim is numbed, and the blood flows. The engorged cone-nose – swollen many times its original size – has long since retreated when the pain begins.

The bite is bad. But the problem comes next. Some cone-noses are infected with a parasite called Trypanosoma cruzi. As they feed, they may defecate. When the victim scratches, the feces – and the parasite – can enter the bloodstream.

Dr. Rosa Maldonado is a UTEP professor working on Chagas.

“In general, when you get infected, you get flu-like systems,” Maldonado said, “a little fever, sometimes a little bit of tachycardia, and you’ve got the parasite just circling in the blood. At the beginning you have those symptoms, and you can confuse it with the flu, which is quite common, or with a severe allergic reaction.”

Those symptoms fade quickly. But about 30 percent of infected people can develop chronic Chagas.

As Monroe suggests, it’s a “silent disease.” The parasite destroys cells as it proliferates. Over years or decades, that compromises organs – usually the colon or heart. In Latin America, it kills as many as 50,000 a year.

How prevalent is the parasite here? It’s hard to know. In 2013, Maldonado found 60 percent of bugs in one remote area were infected. Researchers elsewhere in Texas have found high rates. And the disease is certainly present. Maldonado tested blood from 200 new mothers at one El Paso hospital. Three percent were positive for Chagas.

It’s not a cause for alarm, Maldonado said. But we should be proactive. Maldonado recommends spraying for insects during summer months. Kissing bugs are attracted to light, and they follow rats and mice – yards should be kept free of trash. Cone-noses are most abundant in rural areas. Outdoors enthusiasts should use repellent.

“I think it’s important to be aware what of is around you,” Maldonado said. “To be careful – not to be afraid. Take care of your house. There are cracks? Seal the cracks. Keep the nets of your windows and doors in good shape. If you’re aware, you can take the measures, to avoid, as much as possible, getting infected.”

Kissing bugs are present across West Texas – and in 75 percent of the U.S. Chagas has historically affected low-income countries, and it’s received limited attention. Tests and treatments, which can cure Chagas, exist, but they’re crude. With NIH funding, Maldonado and others are working to improve treatments. She’s also developing a vaccine – which has proved effective on baboons. Climate change may increase the risks. With warmer weather, the bugs are active more of the year.

Best is not to be bitten. Monroe’s ranger was right to be mindful of this West Texas reality.

“It was one of those situations where I had this kind of apocalyptic sense of this threat,” Monroe said. “The information you’ve given me is not all that reassuring – but it’s better to know than to just be making it up I guess. Yes – I’ll sleep in a tent.”