A parasitic disease that can lurk silently in the human heart for decades before triggering fatal cardiac arrest has been officially recognized as endemic in the United States. The CDC's Emerging Infectious Diseases journal published a landmark study in September 2025 — co-authored by researchers from Texas A&M University, the University of Florida, and the Texas Department of State Health Services — concluding that Chagas disease is an endemic disease of the United States, not merely an imported infection from Latin America. The study called for recognition of that endemicity to drive improvements in surveillance, research, and public health responses.
The CDC updated its Chagas disease pages most recently on February 4, 2026, reflecting fresh institutional attention to a disease that has long been undercounted and under-resourced. The update arrives as summer weather activates kissing bugs — the nocturnal blood-feeding insects that spread the Trypanosoma cruzi parasite — across the southern and southwestern United States, where 11 triatomine species have been found in 32 states.
The numbers are striking: approximately 300,000 Americans are estimated to be living with Chagas disease, the vast majority of them without knowing it. Between 2013 and 2023, Texas documented 50 locally acquired cases — meaning people who were infected within the United States, not while traveling to endemic countries. Human cases have been confirmed in California, Arizona, Texas, Tennessee, Louisiana, Missouri, Mississippi, and Arkansas.
How Chagas Disease Spreads and Why It Is So Hard to Detect
Chagas disease is caused by the Trypanosoma cruzi parasite, which is carried by triatomine bugs — colloquially called "kissing bugs" because they tend to bite sleeping humans on or near the face. The bugs hide in cracks in walls, adobe structures, thatched roofs, under mattresses, and near areas where pets sleep. At night, they emerge to feed on blood.
The parasite does not enter through the bite itself — it is transmitted when the bug defecates near the bite wound and the person unknowingly rubs the infected feces into the bite site, an open cut, or near the eyes or mouth. This fecal contamination route is the most common mode of transmission in the Americas. In the United States, infection can also occur through blood transfusions, organ transplants, and from mother to child during pregnancy.
What makes Chagas disease so treacherous is its two-phase natural history. In the acute phase, which occurs in the weeks following infection, many people experience mild symptoms — fever, fatigue, body aches, headache, swelling around the eye if the entry site was near the face (known as Romaña's sign) — or no symptoms at all. This acute phase may resolve without treatment, leading patients and physicians to dismiss it as a passing illness. But the parasite does not leave the body. It enters an indeterminate chronic phase and persists for life.
In approximately 20 to 30 percent of people with chronic Chagas disease, the parasite eventually causes irreversible cardiac damage — primarily cardiomyopathy, abnormal cardiac rhythms, heart block, and sudden cardiac death — or gastrointestinal complications including megaesophagus and megacolon. These complications typically emerge 10 to 30 years after the original infection, in middle-aged adults who often have no memory of a tick-like bite decades earlier.
The Diagnosis Gap That Is Allowing Thousands to Go Untreated
Only eight U.S. states currently require mandatory reporting of Chagas disease: Arizona, Arkansas, Louisiana, Mississippi, Tennessee, Texas, Utah, and Washington, plus two California counties. Without universal mandatory reporting, the true national caseload cannot be accurately estimated. Clinicians outside the traditional endemic South and Southwest are largely unaware of the disease and rarely test for it.
Two antiparasitic drugs, benznidazole and nifurtimox, are approved treatments for Chagas disease. Treatment is most effective in the acute phase and in children with chronic infection — when administered early, it can eliminate the parasite and prevent the cardiac complications that define chronic disease. In adults with established cardiac Chagas disease, treatment can slow progression and reduce the risk of transmission to future children. The CDC's updated website emphasizes that treatment is indicated for all acute or reactivated Chagas cases.
For Americans living in the South, Southwest, or any of the 32 states with known triatomine populations, the practical protective measures are: seal cracks in walls and around windows and doors, remove wood piles and debris from near the home, ensure dogs and cats sleep indoors or in sealed kennels rather than in locations accessible to kissing bugs, and if a triatomine bug is found in the home, do not crush it — instead seal it in a container and submit it to the local health department for testing.
Frequently Asked Questions
Q: What is Chagas disease and is it really in the United States?
A: Yes. Chagas disease, caused by the Trypanosoma cruzi parasite and spread by kissing bugs, has been confirmed in humans in 8 U.S. states, with an estimated 300,000 Americans living with it. A September 2025 CDC study officially recognized it as endemic to the U.S.
Q: How do people get Chagas disease in the United States?
A: Most commonly through contact with feces from an infected kissing bug that enters the body through a bite wound, open cut, or mucous membranes. Transmission can also occur through blood transfusions, organ transplants, or from mother to child during pregnancy.
Q: Why do most people not know they have Chagas disease?
A: Acute infection is often asymptomatic or mild, and the chronic phase is silent for years to decades. Most people are never tested because physician awareness outside endemic areas is low.
Q: What are the long-term consequences of untreated Chagas disease?
A: In approximately 20–30% of chronically infected individuals, Chagas disease causes serious heart disease — including cardiomyopathy, arrhythmias, and sudden cardiac death — or gastrointestinal complications, typically appearing 10–30 years after initial infection.
Q: Is there treatment for Chagas disease?
A: Yes. Benznidazole and nifurtimox are both effective antiparasitic treatments, especially in the acute phase or in children. The CDC recommends treatment for all acute cases and for children with chronic infection.
