Chagas Disease Now Established in California and the Southern United States

Chagas disease, traditionally considered a health threat mainly in Latin America, has now been identified as an endemic issue in California and other southern states across the U.S. This insidious disease, caused by the parasite Trypanosoma cruzi, is transmitted through the bites of infected kissing bugs. In the U.S., there are about a dozen kissing bug species, with four known to carry the parasite in California. Notably, in locations like Los Angeles' Griffith Park, up to a third of kissing bugs have been found infected.

The disease remains largely underdiagnosed in the U.S., with estimates suggesting roughly 300,000 individuals may be unknowingly affected. It is often dormant for years, only becoming apparent when it results in severe complications such as heart attacks, strokes, or sudden death. In Latin America, Chagas causes more fatalities annually than malaria, highlighting its deadly potential.

While most U.S. cases are believed to be imported from endemic countries, recent evidence indicates local transmission might also be occurring. Studies show a significant portion of cases reported in California are acquired within the country. However, because Chagas disease is not a reportable illness statewide, its true prevalence remains uncertain. In Los Angeles County alone, between 2019 and 2023, about 18 confirmed cases were identified, though many may go undiagnosed.

The presence of the parasite in local wildlife—including rodents, raccoons, bats, and other animals—along with the widespread distribution of kissing bugs, suggests that the disease could be more prevalent than currently recognized. Experts advocate for the World Health Organization and CDC to declare Chagas disease endemic in the U.S. to increase awareness, surveillance, and public health interventions.

Medical professionals emphasize that early detection and treatment with antiparasitic medications can prevent serious complications, yet many cases remain undiagnosed due to limited screening. The disease's long-term effects include chronic heart and organ damage, which can severely impair quality of life and increase healthcare costs. Dogs are also susceptible, often developing similar cardiac symptoms, and can serve as reservoirs for the parasite.

Public health awareness and proactive screening are essential as the disease continues to emerge within U.S. borders, especially in states with sizable immigrant populations from endemic regions. Addressing the stigma and increasing knowledge about Chagas disease could save lives and reduce the burden of this silent threat.