Monogenetic parasite is the one which completels its life cycle in one organism only.Example is Entamoeba histolytica which lives in human large intestine.It passes on the cycts through excreta or stool.The cysts when ingested by another individual through contaminated food or water ,will enter in to the intestine of another individual.So one host is enough for Entameoba histolytica.Such parasites are called monogenetic parasites.