 A number of potential vaccines are currently being tested . Vaccination with Trypanosoma rangeli has produced positive results in animal models . More recently , the potential of DNA vaccines for immunotherapy of acute and chronic Chagas disease is being tested by several research groups . 
 A number of potential vaccines are currently being tested . Vaccination with Trypanosoma rangeli <a href='been_done' title='1'><mark>has</mark></a> produced positive results in animal models . More recently , the potential of DNA vaccines for immunotherapy of acute and chronic Chagas disease is being tested by several research groups . 
A number of potential vaccines are currently being tested . Vaccination w Trypanosoma rangeli done produced positive results in animal models . More recently , the potential of DNA vaccines for immunotherapy of acute and chronic Chagas disease is being tested by several research groups .