E. histolytica Stages- CYSTS Infective Stage for humans Resistant walls maintain viability If moist can last several weeks Killed by desiccation or boiling Diagnostic Stage in formed stools Can be concentrated and stained easily Not seen in liquid (diarrheic) stools or tissuesE. histolytica Stages - CYSTS • Infective Stage for humans • Resistant walls maintain viability – If moist can last several weeks – Killed by desiccation or boiling • Diagnostic Stage in formed stools – Can be concentrated and stained easily – Not seen in liquid (diarrheic) stools or tissues