 If symptoms develop during the acute phase , they usually resolve spontaneously within three to eight weeks in approximately 90 % of individuals . Although the symptoms resolve , even with treatment the infection persists and enters a chronic phase . Of individuals with chronic Chagas disease , 60 – 80 % will never develop symptoms ( called indeterminate chronic Chagas disease ) , while the remaining 20 – 40 % will develop life @-@ threatening heart and / or digestive disorders during their lifetime ( called <unk> chronic Chagas disease ) . In 10 % of individuals , the disease progresses directly from the acute form to a symptomatic clinical form of chronic Chagas disease . 
