And it can be as close as your backyard.
The kissing bug is the vector -- or carrier -- for protozoa Trypansoma cruzi. It's a parasite that lives in the gut of the bug and is disseminated through its feces.
When the feces get into the bloodstream of humans, it causes Chagas disease, which ultimately can cause heart failure.
Dr. Sahotra Sarkar is a professor of integrative biology at the University of Texas. He has been studying Chagas disease since 2006. He wrote a paper published in PLoS Neglected Tropical Diseases.
"The insects like to feed on people when they're asleep and tend to bite your lips," said Sarkar. "That's how the bug got its name. But we've seen bites on almost every part of the human body."
Sarkar's team started off studying Chagas disease in Mexico. Each year Chagas disease kills more than 50,000 people in Central and South America.
But recently Sarkar has been alarmed at the overwhelming numbers of the parasite they are finding in Texas.
Eleven counties in South Texas are at highest risk. But this past year, more than half of the bugs collected in Central Texas were found to carry the deadly parasite.
"Three of the species have been found in Travis County," said Sarkar.
"You are not likely to get a lot of them in the middle of the city, but by the time you get to the suburbs and you have areas where there's a fair amount of wood, that's where you'll see them," said Sarkar.
The blood-sucking insect is nocturnal, biting and feeding on animals and humans at night. Bats are one of their favorite food sources.
"As the bug is biting you, slowly as your blood is going into it, the feces get moved out of the body, and the feces are what carries the parasite," said Sarkar.
If the parasitic feces get into your bloodstream, it can bring on flu-like symptoms, with aches and fever.
But after the symptoms have dissipated, the parasite lives on, burrowing into the heart muscle, sometimes for decades until it causes cardiac arrest.
People can be infected for years and not even know it.
"I suspect there are more people than we think who are walking around who don't know they have it," said Sarkar.
Chagas disease can also infect and kill household pets, if they're bitten.
A simple blood test can show if you have Chagas disease, but there is no cure.
It is expected the Texas Health Department will require doctors to report it by 2012.
