<prompt> Most fatal amoebic encephalitis is caused by ?E.histolyticaNaeglariaE. disparAcanthamoeba  <response>: Ans. is b i.e., Naeglaria . Amongst the given options Naeglaria and Acanthamoeba cause amoebic encephalitis. The prognosis of Naeglaria encephalitis is uniformaly poor, most patients die within a week.---Harrison Acanthamoeba encephalitis follows a more indolent course.--- Harrison . So, amongst the given options Naeglaria causes most fatal amoebic encephalitis . 