CDC Officially Recognizes Chagas Disease as Endemic in the United States, With an Estimated 300,000 Americans Affected
Key Insights
The CDC (search)'s Emerging Infectious Diseases journal published a landmark study in September 2025 officially recognizing Chagas disease (search) as endemic in the United States, not merely an imported infection.
Approximately 300,000 Americans are estimated to be living with Chagas disease (search), with locally acquired cases confirmed in at least eight states including Texas, California, and Arizona.
The disease, caused by the Trypanosoma cruzi (search) parasite and spread by kissing bugs, can remain silent for decades before causing fatal cardiac complications in 20–30% of chronically infected individuals.
A parasitic infection capable of hiding silently in the human heart for decades before triggering fatal cardiac arrest has been officially recognized as endemic in the United States. The CDC (search)'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 (search) is no longer merely an imported infection from Latin America but an endemic disease of the United States. The study called for recognition of that endemicity to drive improvements in surveillance, research, and public health responses.
The CDC (search) updated its Chagas disease (search) 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 (search) 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 (search), the vast majority without knowing it. Between 2013 and 2023, Texas alone documented 50 locally acquired cases—meaning people 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.
A Two-Phase Disease That Evades Detection
Chagas disease (search) is caused by the Trypanosoma cruzi (search) parasite, 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 (search) so treacherous is its two-phase natural history. In the acute phase, occurring 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 (search), 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
Only eight U.S. states currently require mandatory reporting of Chagas disease (search): 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.
This pattern of underdiagnosis mirrors challenges documented in endemic regions of Latin America. A retrospective analysis published in PLOS Neglected Tropical Diseases examining Chagas disease (search) management in two municipalities in Bahia, Brazil, between 2019 and 2023 found that serological testing expanded substantially only where engaged clinicians—described as local "Chagas champions"—drove screening efforts within primary care. In Tremedal, 39% of serological tests were concentrated among just three family physicians, while testing in neighboring Novo Horizonte remained minimal until 2023, relying on a single professional from one urban health unit.
Treatment Options and Barriers
Two antiparasitic drugs, benznidazole and nifurtimox, are approved treatments for Chagas disease (search). 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 (search)'s updated website emphasizes that treatment is indicated for all acute or reactivated Chagas cases.
However, the Brazilian analysis highlighted significant gaps in guideline-concordant care. Despite identifying individuals eligible for etiological treatment according to the Brazilian Clinical Protocol and Therapeutic Guidelines, documentation of benznidazole use was limited to two cases—both in individuals older than 50 years. Notably, the BENEFIT trial demonstrated that benznidazole did not significantly reduce cardiac clinical deterioration in patients with established Chagas cardiomyopathy, suggesting these may not have been optimal candidates. Meanwhile, several younger individuals who would more likely benefit from treatment did not receive it, including a pediatric patient aged 10–19 years whose family relocated before treatment could be initiated.
Practical Protective Measures
For Americans living in the South, Southwest, or any of the 32 states with known triatomine populations, the CDC (search) recommends sealing cracks in walls and around windows and doors, removing wood piles and debris from near the home, ensuring dogs and cats sleep indoors or in sealed kennels, and—if a triatomine bug is found in the home—not crushing it but instead sealing it in a container and submitting it to the local health department for testing.
The official recognition of Chagas disease (search) as endemic in the United States marks a pivotal shift in public health policy, one that researchers hope will catalyze improved surveillance, expanded clinician education, and earlier intervention for the estimated 300,000 Americans currently living with this silent but potentially fatal infection.