The United States Trypanosoma cruzi Infection Study: evidence for vector‐borne transmission of the parasite that causes Chagas disease among United States blood donors

Abstract

This report adds 16 cases, including one from the Mississippi investigation, of chronic T. cruzi infection presumably acquired via vector-borne transmission in the United States to the previously reported seven cases. The estimated prevalence of autochthonous infections based on this study is 1 in 354,000 donors. Determining US foci of vector-borne transmission is needed to better assess risk for infection.

Evidence of Autochthonous Chagas Disease in Southeastern Texas

“…The US CDC recently reported rare cases of domestically acquired infection from a large nationwide follow-up study of infected blood donors. 12 In contrast, our pilot study of 17 RIPA-positive blood donors in the Houston area found 35% (6 of 17) with evidence of locally acquired infection.…”

“…These two exposure activities have also been previously described in United States domestically acquired case reports. 12 Inadequate temporary lodging and/or increased exposure to the vector during these activities may be important contributing factors for transmission associated with these outdoor activities. 19 Exposure to infectious blood while skinning a dead animal without gloves is another possible important transmission route.…”

“…9 The United States is considered a non-endemic country for transmission, with rare reports of locally acquired human cases occurring. 12 Since active blood donor screening began in 2007; we have begun to learn more about the burden and source of infection in this country. The US CDC recently reported rare cases of domestically acquired infection from a large nationwide follow-up study of infected blood donors.…”

“…Duration of exposure in an endemic country associated with risk for infection is not known; however, trips 2 weeks are not considered significant according to multiple published studies. 12,[15][16][17][18] Additionally, spending the night in a rural area is considered higher risk for transmission than daytrips when traveling in an endemic country. Finally, Mexico has a low T. cruzi seroprevalence, further supporting short travel to this country as an unlikely source of infection.…”

“…12,13 To better understand transmission sources in southeast Texas, we performed a pilot study of infected blood donors assessing source of infection and cardiac outcomes. 14 We present five cases of suspected autochthonous Chagas disease in Texas residents who do not have a significant history of travel to a foreign endemic country.…”