Experts Reassess Chagas Disease, Evaluate the Case for Reclassification in the US

Some experts are proposing that the United States be considered endemic for Chagas disease (trypanosomiasis), a bloodborne disease that is becoming increasingly recognized in southern states. The experts lay out the case for endemicity in a perspective article published in Emerging Infectious Diseases.

Chagas disease, also known as the kissing bug disease and American trypanosomiasis, is caused by the parasite Trypanosoma cruzi. It is transmitted through the feces of infected triatomine bugs (kissing bugs) that bite humans on the face at night. If left untreated, the disease can lead to serious health issues, including heart failure, arrhythmias and digestive problems.

The U.S. is currently classified as non-endemic for Chagas disease by the World Health Organization (WHO) and the Pan American Health Organization (PAHO), though it is considered endemic in 21 other countries in the Americas.

Triatomine bugs have been documented in 32 US states and are most common in southern states. The authors noted that it is hard to assess whether the species is expanding in geographic reach or numbers because available data are inadequate, primarily due to a lack of standardized surveillance over time. However, frequent encounters with triatomines in humans have been recognized in the domestic and peridomestic habitat and have increased in research attention.

In addition, cases appear to be common in dogs (431 cases in 2013-15) and have been documented in cats, horses, rats and non-human primates. Local cases of T. cruzi infections have been identified in California, Arizona, Texas, Tennessee, Louisiana, Missouri, Mississippi, and Arkansas. A systematic literature review found 29 confirmed and 47 suspected locally acquired cases of Chagas disease between 2000 and 2018. However, human Chagas disease is a notifiable disease in only eight states and two California counties.

According to the authors, maintaining the non-endemic classification in the U.S. may contribute to limited awareness among physicians and veterinarians regarding the potential for human and animal exposure to T. cruzi, which could hinder appropriate differential diagnosis and possibly lead to underreporting.

Considerations for Blood Collectors

Only a few cases of blood transfusion- or organ transplantation-transmitted T. cruzi cases have been reported in the U.S., but it is well accepted that unrecognized cases have occurred. Furthermore, donor screening questions have not reliably identify risk in U.S. blood donors.

The Food and Drug Administration recommends that allogeneic donors should be tested at least once using a licensed test for antibodies to T. cruzi. Donors who test nonreactive are qualified to return to donate without testing of subsequent donations.

Additional information is available on AABB’s Chagas disease web page.