In the heart of Illinois, while researching wildlife disease, I made a discovery that stunned me: More than half of the raccoons I sampled were infected with Trypanosoma cruzi, the parasite that causes Chagas disease.
Most Americans have never heard of it. But this neglected tropical disease is no longer confined to the tropics. It’s here, in the United States, spreading silently in wildlife.
Chagas disease can lie dormant in the human body for years before leading to heart failure, stroke, arrhythmias, or sudden death. Once symptoms appear, the damage is often irreversible. The parasite is spread by triatomine insects, also known as “kissing bugs,” which feed on the blood of infected animals like raccoons, opossums, and rodents. They defecate near the bite, and if the feces enter broken skin or mucous membranes, the parasite can infect humans. In rare cases, it has also been transmitted via organ transplant, blood transfusion, and congenital exposure.
Although Chagas disease is endemic to Latin America and a major public health concern there, it remains largely overlooked in the United States. The Centers for Disease Control and Prevention estimates that around 300,000 people living in the United States are infected with Trypanosoma cruzi. Many were born in endemic regions of Mexico, Central America, and South America, yet most don’t know they are infected.
But the popular idea that this disease only affects immigrants or travelers is dangerously outdated. My research confirms that T. cruzi is actively circulating in U.S. wildlife, and Other studies have found infected kissing bugs and mammalian hosts in Texas, California, Louisiana, and now the Midwest.
While Trypanosoma cruzi in raccoons and triatomine bugs doesn’t guarantee human infection, the ecological conditions for spillover already exist, and in some cases, transmission has likely occurred. A recent review in the journal Life found about 90 confirmed or suspected locally acquired Chagas cases in the U.S. between 2000 and 2020, mostly in Texas but also in Arkansas, Missouri, Louisiana, and California. More recently, a field study in Florida, published in PLOS Neglected Tropical Diseases, revealed that nearly 35% of triatomine bugs collected inside homes tested positive for T. cruzi, and 23% had fed on humans, confirming direct human-vector contact and ongoing potential for unnoticed transmission. A 2022 study estimated about 10,000 locally acquired cases in the U.S.
Although locally acquired Chagas cases remain relatively rare in the United States, some researchers are beginning to raise concerns that could shift this dynamic.
A University of Florida Extension report states that the risk of human contact with infected triatomine bugs may increase in areas where homes border wooded landscapes or include features like dog shelters, poultry sheds, or stacked firewood. These environments create ideal hiding spots and blood sources for the insects, raising the chances they’ll enter homes. As climate change and land development reshape ecosystems, monitoring these risk factors is critical to staying ahead of potential disease spillover.
What’s worse is how unprepared we are. Most doctors in the U.S. don’t consider Chagas disease in their differential diagnoses. Routine testing is nearly nonexistent. There’s no standardized national surveillance, and most infections are only discovered incidentally, such as during blood donor screening. By then, it’s often too late.
Even among those familiar with Chagas, there’s a misconception that it’s rare or imported. My fieldwork contradicts that narrative. If raccoons in rural Illinois are carrying this parasite in such high numbers, what does that mean for human exposure? People living in rural and wooded areas, hunters, campers, and agricultural workers are all potentially at risk, especially as triatomine bugs expand their geographic range due to climate change and environmental shifts.
The CDC has published data and guidelines on T. cruzi, but much of the clinical community remains unaware of the disease’s domestic relevance. This knowledge gap is both preventable and dangerous. Every year we delay action, we miss opportunities for early detection, treatment, and public education.
To be clear, Chagas disease is treatable if caught early. Antiparasitic medications like benznidazole can reduce parasite load and prevent progression, particularly in children and newly infected patients, according to the CDC. But we must first recognize it exists here, and test for it accordingly.
The solution is not panic but preparation. We need:
- Awareness campaigns to educate clinicians and the public
- Expanded diagnostic access, especially in high-risk regions
- Targeted screening for patients with unexplained cardiac issues in endemic zones
- Continued wildlife surveillance to monitor spread
My experience as a research scientist showed me that the line between neglected and recognized diseases is not biology, it’s attention. Chagas disease has all the warning signs of an emerging public health crisis: silent spread, climate-driven expansion, low awareness, and long-term health consequences. What it lacks is urgency.
We’ve seen this before. Covid-19, mpox, and now rising tick-borne diseases, all emerged from complex relationships between humans, wildlife, and environmental change. Trypanosoma cruzi is no different. It’s not a matter of if this becomes a bigger problem in the U.S., but how soon, and whether we will be ready. It’s time to stop underestimating Chagas disease and start treating it like the threat it truly is.
Esther Onuselogu, M.Sc., is a biological sciences researcher with a focus on public health. Her thesis is on Trypanosoma cruzi infection in U.S. wildlife. She is passionate about infectious disease awareness and public health equity.
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