What is the ‘kissing bug’ disease, and should Texans be worried?

Kissing bugs may sound charming, but with one bite, these insects can spread a dangerous parasitic infection: Chagas disease. Affecting more than 7 million people worldwide, mostly in Latin America, the disease should now be considered endemic or regularly occurring in the United States, according to a new report.

In the Center for Disease Control and Prevention’s Emerging Infectious Diseases journal, the report’s authors note Chagas disease is already endemic in 21 countries across the Americas—and point to mounting evidence of the disease-causing parasite being found among triatomines (aka “kissing bugs”), other wildlife, captive animals and pets in the U.S.

U.S.-acquired cases have been reported in eight states, “most notably in Texas,” the report said, adding that calling the U.S. a non-endemic country “perpetuates low awareness and underreporting.”

Texas has documented cases of Chagas disease, also known as kissing bug disease, since the 1930s. The first case known to have been acquired in the U.S. happened in Corpus Christi in 1955. From 2013 to 2023, Texas health officials recorded 273 cases of Chagas disease in the state, 51 locally acquired. North Texas counties, including Dallas, have reported cases, but all infections were contracted elsewhere.

Chagas disease shouldn’t be a big concern for Dallas-Fort Worth residents, said Dr. Krutika Kuppalli, an infectious disease specialist at UT Southwestern, and Dr. Philip Huang, director of Dallas County’s Health and Human Services. But awareness matters.

Here’s what to know:

What causes Chagas disease?

Chagas is caused by Trypanosoma cruzi, a comma-shaped blood parasite found across the Americas; in the U.S., it appears mostly in the South. According to the World Health Organization, the infection leads to more than 10,000 deaths every year.

How it spreads is a bit gross: After a kissing bug sucks an infected animal’s blood, the parasite enters the bug’s guts and turns into an infective form that’s shed in the bug’s feces.

“The parasite eats so much blood that its size increases tenfold,” said Igor Almeida, a professor of biological sciences at the University of Texas at El Paso, who has spent decades studying Chagas disease. “This causes pressure on the intestine of the bugs, forcing not only feces but also urine to come out together.”

If infected feces from a kissing bug are rubbed into a bite—or get into an eye or the mouth—the parasite can enter the body of its new host. (The kissing bug gets its name from the belief that it mostly bites around the mouth or eyes, like a kiss.)

Other routes of infection include contaminated blood transfusions or organ transplants, mother-to-child transmission during pregnancy and swallowing food or drink tainted with infected bugs or their feces, said Rosa Maldonado, another professor of biological sciences at UTEP who has spent decades studying Chagas disease.

Where is Chagas disease found in Texas?

Chagas cases turn up across Texas. But locally acquired infections—caught here rather than during travel elsewhere—cluster in south-central and south Texas, said Bonny Mayes, an epidemiologist with the Texas Department of State Health Services.

A wide range of Texas wildlife carries the disease-causing parasite, including about half of the kissing bugs tested in the state, said Gabriel Hamer, an entomology professor at Texas A&M University and co-author of the new report. In North Texas, however, the most common species of kissing bug is less efficient than other species at passing the parasite to people.

That species, called the eastern bloodsucking conenose, “might wait a bit longer to poop,” Hamer said, “and that just means humans are a little bit less likely to get exposed.”

Kissing bugs are nocturnal. By day they wedge into cracks and crevices—in walls, roofs and other hideouts. At night they emerge to feed, homing in on sleeping hosts.

“Most exposure of animals would be outside,” Hamer said. “But the adult kissing bug can fly—they’re attracted to light. They do end up indoors fairly regularly. So it’s definitely possible for dogs or humans to get exposed inside.”

Warming temperatures are pushing some disease-carrying insects, such as ticks and mosquitoes, into new territory. Whether that’s happening with kissing bugs is unclear, Hamer said. They favor tropical and subtropical climates, and the data is too limited to show a shift in distribution due to a lack of standardized monitoring, Hamer said.

How is Chagas disease diagnosed and treated?

Once infected with Chagas, the disease unfolds in two phases: acute and chronic. The acute phase occurs in the first weeks to months after infection and often has no symptoms. When the acute phase does have symptoms, they’re usually mild and can include fever, fatigue and body aches; sometimes, there can be eyelid swelling, called the Romaña sign.

About 20% to 30% of asymptomatic people can develop complications, Kuppalli said, the most common being problems with the heart or the digestive system. These issues stem from the fact that the parasite tends to hide in the heart and digestive muscles, according to the WHO.

When an acute infection goes untreated or isn’t successfully treated, chronic Chagas can develop and last for several years, even a lifetime.

Babies born with Chagas disease typically show mild or no symptoms, but if left untreated, the infection will last a lifetime, according to the CDC.

Early diagnosis and treatment are important because antiparasitic drugs work best in this window.

Tests for acute disease include a blood smear and genetic testing for the parasite’s DNA, the latter of which is far more specific and sensitive, Mayes said.

Two federally approved antiparasitic treatments—benznidazole and nifurtimox— work best in the acute phase, although side effects can limit how well people tolerate treatment, Mayes said. Once infection becomes chronic, these drugs generally don’t cure Chagas; they may, however, reduce parasite levels and help slow disease progression.

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