Why Is Chagas Disease Frequently Missed in the US?

Many patients with Chagas disease in the United States ask a very common and understandable question: Why did it take my doctors years to figure this out? The short answer is that Chagas disease is frequently underdiagnosed in the U.S. because it is relatively rare here, meaning most American doctors do not actively look for it ^[1][2]. Furthermore, there is no routine screening for it during standard check-ups ^[1], and the symptoms often mimic common age-related conditions like heart failure or digestive issues ^[3][4].

While years of misdiagnosis can be incredibly frustrating, knowing why it happens can help you understand your medical journey. Even if your diagnosis was delayed, there are many effective ways to manage and treat the symptoms so you can protect your quality of life.

Here is a closer look at the specific reasons why Chagas disease is often misdiagnosed or missed entirely by American healthcare providers.

Low Clinical Suspicion

Doctors in the United States often follow the saying, “When you hear hoofbeats, think horses, not zebras.” Because the parasite that causes Chagas disease (Trypanosoma cruzi) is mainly found in rural parts of Latin America, the disease is not considered endemic (naturally common) to most of the U.S. ^[5][1]. As a result, American healthcare providers receive very little education on Chagas disease ^[6][4]. Even when treating patients who lived in areas where the disease is common, doctors often lack the awareness to include Chagas disease in their list of possible diagnoses ^[7][1][6].

A “Silent” Disease for Decades

Chagas disease is notoriously difficult to track because it typically features a decades-long latent phase ^[8][9]. Most people are infected during childhood. While there is a short acute phase that might cause a mild fever or a swollen eyelid, these symptoms pass quickly and are easily forgotten. The parasite then enters a “silent” or chronic indeterminate phase that can last for 20 to 30 years without causing any noticeable health issues ^[8][10]. By the time symptoms appear in adulthood, the original infection event is decades in the past, making it difficult for both the patient and the doctor to connect the dots ^[8][10].

Symptoms Mimic Common Conditions

When chronic Chagas disease eventually causes damage, it typically targets the heart or the digestive system. Unfortunately, these symptoms are virtually identical to other common conditions seen in older adults in the U.S.:

• Heart Issues: Chronic Chagasic cardiomyopathy often presents as an irregular heartbeat (arrhythmia), heart block, or an enlarged, weakened heart ^[11][3]. In the U.S., doctors typically assume these symptoms are caused by standard age-related heart failure, coronary artery disease, or idiopathic dilated cardiomyopathy (heart enlargement with an unknown cause) ^[11][12].
• Digestive Issues: Gastrointestinal Chagas disease can cause severe damage to the esophagus or colon, leading to intense swallowing difficulties or chronic constipation ^[4]. These symptoms are frequently misdiagnosed as achalasia (a rare swallowing disorder) or severe irritable bowel syndrome ^[4].

Lack of Routine Screening and Clear Testing Rules

In the United States, there is no universal screening protocol for Chagas disease ^[1]. It is not checked during a standard annual physical, and it is not part of a routine blood panel ^[13][14]. While experts recommend targeted screening for high-risk individuals—such as people born in parts of Mexico, Central America, or South America—these guidelines are not widely practiced by primary care doctors ^[1][14].

Because it is not caught at the doctor’s office, one of the most common ways people in the U.S. discover they have asymptomatic Chagas disease is actually by attempting to donate blood, as blood banks routinely screen first-time donors for the parasite ^[1].

Diagnosing the disease in a clinic requires specialized blood tests (serological assays) that most local facilities do not have on hand ^[15]. Furthermore, because there is a lack of consensus on the exact testing rules and diagnostic algorithms that should be used in non-endemic countries like the U.S., official screening programs are difficult to implement ^[16].

Risk to Family Members

Because routine testing isn’t standard, it is important to know that doctors may recommend screening the family members of someone who has just been diagnosed ^[1]. Chagas disease is not spread through casual contact like hugging, kissing, or sharing food. Instead, family screening is recommended because the disease can be passed from a mother to her baby during pregnancy, or because family members may have shared the same environmental exposure (such as living in the same rural area in Latin America where the parasite is common) ^[1][14].

Advocacy Tip: If you grew up in a high-risk area and have unexplained heart or digestive issues, you do not have to wait for your doctor to guess the cause. You can explicitly advocate for yourself by asking your provider for a “Chagas serology test.”