Nudging medical practice change one regulation at a time.

mission. “We don’t know how big a problem it is,” said Susan P. Montgomery, DVM, MPH, epidemiology team lead in the CDC’s parasitic diseases branch. Of the 17 Texas blood donors with confirmed Chagas disease in her study, Garcia noted 6 were suspected to have acquired the infection close to home. However, blood donor screening likely detects only a small percentage of local or imported US cases, because those at highest risk are underrepresented among donors, Garcia said. Furthermore, not all those with confirmed Chagas had traditional risk factors, such as spending time in an endemic country and staying in areas with substandard housing (GarciaMNetal.Am J Trop Med Hyg. 2015;92[2]:325-330). The researchershave found locally transmitted cases among peoplewho live in rural areas or spend substantial amounts of time outdoors. Garcia explained that local transmission in theUnitedStates likely canbe traced back to small mammals, such as wood rats, squirrels, possums, and skunks that act as reservoirs for T cruzi and serve as a source of constant blood meals for the triatomine bugs with which they tend to cohabitate. Theseanimals thenmaketheirhomes insubstandard human housing and bring the insects with them, leading to human exposure to the parasite. In linewith thismode of local transmission, Garcia and her colleagues found a high prevalence of T cruzi infection among triatomine bugs in southwestern Texas. They reported at the ASTMH meeting that three-quartersof the40bugscollectedfrom June 2013 to January 2014 were infected. The insects were predominantly collected near homes in rural areas, andananalysis of the infected insects found that half had recently fed on humans. Another potentially underappreciated source of local transmission is mother-tochild transmission,which canoccur in 1%to 10% of pregnancies in infected women. Montgomery noted 1 confirmed case of T cruzi infection in an infant born in Virginia toamother likely infected inBolivia (MMWR Morb Mortal Wkly Rep. 2012;61[26]:477479).However, sheandBernestimated that at least 63 and as many as 315 congenital T cruzi infectionsoccureachyear in theUnited States (Bern C andMontgomery SP. Clin Infect Dis. 2009;49:e52-e54). “The biggest thing we learned is that people...cangetChagaseven if theyhaven’t left the country,” Garcia said.