The Diagnosis We're All Missing, and Why That Must Change

Rachel R. Marcus, MD


April 14, 2021

Do you take care of Latin-American immigrants or their children? Have any of them had conduction abnormalities on their ECG, a pacemaker, bifascicular block, or heart failure? Have you delivered any babies to immigrant moms?

And for how many of those patients did you consider the diagnosis of Chagas disease?

If your medical school was anything like mine, you were taught that Chagas disease (or "kissing bug disease") was an illness of Latin America, and that if we were "lucky," we'd see this "zebra" once in our career.

Thanks to the efforts of Sheba Meymandi, a cardiologist in Los Angeles county who looked around her waiting room and thought, These folks are all from Chagas-endemic countries; I better see if they have Chagas disease, we now know the following:

  • 1.24% of Latin American–born immigrants from Chagas-endemic countries have this infection, but immigrants from certain areas can have risks as high as 3%-5% (El Salvador; Oaxaca, Mexico).

  • 5% of the same demographic with conduction abnormalities will have Chagas, with 7.5% of those with pacemakers having Chagas as the cause of their conduction disease.

  • A whopping 18% of these immigrants with bifascicular block will have Chagas disease, and between 13% and 19% of this group with nonischemic cardiomyopathy will have Chagas as the cause.

  • There are an estimated 300,000 cases in the United States, with an estimated 63-315 newborns born with congenital Chagas each year, some of whom present with TORCH-like illnesses (hepatosplenomegaly, thrombocytopenia, jaundice, fever, lethargy, anemia, etc.).

Eight years into my work as the medical director of the nonprofit LASOCHA (Latin American Society of Chagas), we have helped make the diagnosis in approximately 200 individuals, and have a clinic of over 80 people to provide basic follow-up care and antiparasitic therapy when appropriate.

These patients face a healthcare system with barriers to care that are too numerous to count, but include their being uninsured, poor, and having low health literacy and limited English proficiency, as well as fear of being deported. In addition, the doctors they see, when asked about Chagas, reply, "I've never seen a case," "We don't have that here," or "I don't know how to test for it or treat it." And now, with FDA approval of benznidazole, they are treating cases that have not been confirmed as truly positive, and using inappropriate dosages of a medication that is toxic and requires careful follow-up.

Furthermore, recent case reports suggest that even in the superspecialized setting of transplant infectious disease, patients are both getting organs from Chagas-positive donors or getting transplanted with underlying Chagas disease, and developing reactivation illness that could have been prevented with appropriate surveillance.

Screening and Early Diagnosis

Making an early diagnosis is critical, and as always, prevention is even better. Although data on treatment efficacy in adults are limited, neonates and children can be cured if treated promptly with antiparasitic medication (benznidazole) after diagnosis, and treatment of women of childbearing age before pregnancy appears to dramatically reduce the risk for maternal-fetal transmission. As a result, routine screening of women of childbearing age in the prenatal or OB setting is recommended by the CDC.

Screening of pregnant women is cost-effective and allows for downstream testing of infected women that will allow for their children to be treated early to prevent disease. Furthermore, even if antiparasitic therapy isn't proven to be helpful in adults, guidelines suggest offering treatment to those who have not yet suffered heart damage from the illness.

Any woman with Chagas disease at any stage should have all children screened. For relatives of any case, family member screening should be offered, as the risk in family members is 7.4 times higher than that of the general population. Any patient who undergoes transplant immunosuppression should be prospectively evaluated by PCR/buffy coat analysis for subclinical signs of reactivation.

The test for Chagas disease is a serologic assay for Trypanosoma cruzi IgG antibodies. When results are positive, this test must be confirmed through the CDC before making the diagnosis.

In patients with established cardiomyopathy, particularly at a more advanced age, antiparasitic therapy is not helpful — but the diagnosis still matters. Chagas disease is a virulent cardiomyopathy causing both lethal arrhythmias and strokes at ejection fractions that would not concern most cardiologists. These patients deserve a disease-specific imaging process to identify and prevent these catastrophic events.

Call to Action

Little about this disease is simple: the marginalization of the patients, the gaps in knowledge about why only 20%-30% of infected individuals develop clinical disease, the lack of evidence base to guide medical therapy in several clinical situations, and the cost of the evaluation/treatment of patients who are uninsured.

But none of these are good reasons for us to continue to ignore this neglected tropical disease, which is why the World Health Assembly has declared April 14 to be World Chagas Day. Those of us in the Chagas specialty community in the United States urge you to consider this diagnosis, order the test, and provide your patients with the care they need for this potentially lethal yet preventable disease.

Rachel R. Marcus, MD, is a cardiologist with a longstanding commitment to working with underserved communities in the United States and abroad. She is the medical director of the nonprofit Latin American Society of Chagas.

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