 <unk> of donated blood , blood components , and solid organ donors , as well as donors of cells , tissues , and cell and tissue products for T. cruzi is mandated in all Chagas @-@ endemic countries and has been implemented . Approximately 300 @,@ 000 infected people live in the United States , which is likely the result of immigration from Latin American countries , and there have been only 23 human cases of domestically acquired vector @-@ borne Chagas disease reported between 1955 and 2014 . With increased population movements , the possibility of transmission by blood transfusion became more substantial in the United States . <unk> blood and tissue products are now actively screened in the U.S. , thus addressing and <unk> this risk . 
