Chagas disease (Chagas), a vector-borne infection caused by the protozoan parasite Trypanosoma cruzi, is endemic to Central and South America. An estimated 100 million people are at risk for the disease and 8-10 million people worldwide are infected. The often-cited statistic of approximately 300,000 cases in the United States is likely to be a marked underestimation of the true burden of disease. The most pressing issues from a public health perspective are congenital transmission, chronic disease leading to cardiac and other complications (e.g. gastrointestinal), and a lack of awareness about Chagas among both healthcare providers (HCPs) and at-risk populations.
Few studies have been done to determine the rate of congenital transmission of Chagas. Current estimates place it at 3-10%. Most children are born asymptomatic, so it is likely that many cases of congenital transmission are being missed. Ideally, women would be identified before conception, but screening programs for pregnant women and their neonates can allow for treatment of children who are identified, treatment of women after delivery, and prevention of transmission in subsequent pregnancies. Benznidazole is FDA-approved for use in children age 2–12 years but can be given off-label for infected infants. The cost-effectiveness of congenital screening programs has been demonstrated in the United States when maternal prevalence is greater than 0.06%. It is clear that expanded testing for congenital Chagas is critical.
The worst health outcomes for individuals with Chagas occur in the estimated 30% who develop potentially fatal cardiac complications. These include conduction system abnormalities, heart failure, thromboembolic events, and other cardiac-related morbidity. In states with high insurance coverage such as Massachusetts (the uninsured rate is 3.8%) and even more so in states with lower levels of insurance coverage, Chagas could result in a substantial burden on the healthcare system, as has been demonstrated in other settings. Across the US, Chagas has been estimated to cost the healthcare system $118.2 million annually.
Lack of awareness
The lack of awareness about Chagas among HCPs in the United States is staggering. From 2011-2018, CDC released enough benznidazole to treat ~55 people each year; these data suggest that <0.3% of infected persons in the US received treatment. Even among infectious disease (ID) specialists, knowledge about screening and testing is relatively low. However, many at-risk patients will never even make it to an ID physician. The HCPs who are most likely to see these patients are usually those working in general internal medicine (GIM) family medicine (FM), pediatrics (PEDS), obstetrics and gynecology (OB/GYN), and, if the patient becomes symptomatic, cardiology. Two separate studies found that OB/GYN specialists had the lowest level of knowledge among specialists surveyed, although cardiologists and primary care physicians did not fare much better. We found at our hospital, Boston Medical Center (BMC), that among 3057 patients from Chagas-endemic countries with cardiac complications potentially due to Chagas, only 42 (1.4%) had been tested for Chagas over 5 years (Wheelock A et al., manuscript under review). These data suggest there is a marked need to educate providers about Chagas. Finally, at-risk populations themselves are generally not aware of Chagas, even when coming from endemic areas.
For More Information:
- CDC Chagas Webpage
- WHO Chagas Webpage
- PAHO Chagas Webpage
- World Heart Federation Voices of Chagas Video
- Strong Hearts Website