 Furthermore, infections by "E. vogeli" and "E. oligarthrus" (polycystic echinococcosis) are considered to be the rarest form of echinococcosis.As of 2010 it caused about 1200 deaths, down from 2000 in 1990.The Largest hydatid cyst contained 37 litres of fluid and was removed from a 80 year old at the King Fahd Central Hospital in Jizan, Saudi Arabia, on 12 January 2005.