Naturally Occurring Trypanasoma Cruzi in Maryland — Who Knew?

BACKGROUND: Chagas disease is a potentially life threatening disease caused by the parasite Trypanosoma cruzi, which is naturally transmitted by triatomine bugs.  As many as 8,000,000 people in Mexico, Central America, and South America have Chagas disease, most of whom do not know they are infected. Triatomine bugs are found in the southern United States, but vectorborne cases of Chagas disease in these states occur infrequently. Although Chagas disease is not reportable in Maryland, the Maryland Department of Health and Mental Hygiene (DHMH) is consulted to coordinate testing of and treatment for the disease with the Centers for Disease Control and Prevention (CDC). In 2014, DHMH was consulted regarding two triatomine bugs collected from a Maryland residence that were known to have bitten at least two household members.

METHODS: The triatomine bugs were sent to the CDC for definitive identification and testing for T. cruzi by polymerase chain reaction (PCR).   Testing decisions for the household residents were made based on results in the bugs and after reviewing the medical literature for evidence of T. cruzi in Maryland reservoirs.  We reviewed consultations to DHMH for triatomine bugs and T. cruzi in 2014 and 2015. 

RESULTS: The CDC identified Triatoma lecticularia and T. sanguisuga and confirmed infection with T. cruzi by PCR in both.  Review of the literature revealed previous detection of T. cruzi in raccoons in Maryland.  Three household members were negative for T. cruzi by enzyme immunoassay, immunoblot, and multitarget PCR as tested by CDC.  Recommendations were made to consult an exterminator to ensure the house was rid of triatomine bugs.  In 2014 and 2015, DHMH received four additional inquiries regarding possible triatomine bugs collected from homes in various Maryland counties, all of which followed news of Chagas disease in the popular media. For each of these inquiries, a Maryland Department of Agriculture entomologist identified the bugs as not triatomines.  DHMH coordinated with CDC for testing of and treatment for three imported cases, one congenital case, and one transplant recipient who required monitoring because the donor was seropositive for T. cruzi.

CONCLUSIONS: Healthcare providers and public health professionals should be aware that although unlikely, T. cruzi could be naturally transmitted in Maryland.  Chagas disease is not a reportable disease in Maryland, but public health professionals should identify entomologic support for identification of bugs and be familiar with the disease so they can respond to public inquiries and coordinate with CDC.