In epidemiology, an endemic is a disease that persists constantly in a given human population without the need for external inputs. The exact prevalence rate of an endemic disease may vary over time, but it is always present at a rate greater than zero (Porta 2008). In biogeography, an endemic organism is exclusively native to a place or biota. Endemic organisms are typically found on remote islands (e.g. Hawaii), rugged highlands (e.g. Ethiopia) or endorheic water bodies (e.g. Lake Baikal).