Neglected tropical diseases – a diverse group of about 17 illnesses – are normally associated with the poorest populations in developing countries. But one of them, Chagas disease, doesn't quite fit the bill, and might be much more widespread in Texas than previously thought. When analyzing the insects that transmit the disease, caused by a parasite, researchers found that a worrying proportion of them were infected.

“It surprised me that so many of them were carrying the parasite,” said Rosa A. Maldonado, who led the study published in Acta Tropica. “I was expecting to have some, but this is quite high.” The disease is caused by the parasite Trypanosoma cruzi, which spends half its life in insects known as “kissing bugs,” and the rest in a mammal host. It is transmitted when a bug bites its prey to feed on their blood. While filling up on the blood, the bug will often defecate, giving the T.cruzi – which lives in the insect’s gut – the perfect chance to swap hosts via the bite wound.

When in humans, T. cruzi can live there for decades, causing Chagas disease. This can manifest itself in one of two phases, either acute or chronic. The acute phase is normally difficult to diagnose, as symptoms range from nothing at all to various common problems such as fever, headaches, and vomiting. It can last from a few weeks to a few months. The danger comes for the 30% that will go on to develop chronic Chagas disease, which can lead to cardiac and intestinal complications such as an enlarged heart, cardiac arrest, or enlarged colon.

Also known by the more technical term American trypanosomiasis, Chagas is primarily a problem in Latin America, though it has spread to other regions in more modern times and is becoming more of an issue in the United States. It’s thought that around 6 to 7 million people are infected globally, although if treated soon after infection, it is curable. It can also be a major health problem for man’s best friend, as dogs often have the unfortunate habit of eating the kissing bugs and getting infected.

Examining the insects at a research station around 160 kilometers (100 miles) north of the U.S.–Mexico border, researchers from the University of Texas at El Paso found that a worrying 61% of bugs sampled were infected with the parasite, and thus had the potential to cause Chagas. “Doctors usually don't consider Chagas disease when they diagnose patients, so they need to be aware of its prevalence here,” explains Maldonado.

The researchers hope that this work will shed light on an often sidelined disease that is gaining in prevalence in the United States. Having sampled a rural area, the scientists plan next on looking at the parasite's occurrence in kissing bugs, dogs, and cats in the urban city of El Paso.