**2.1 Geographical distribution**

Epidemiologically, no clear disease associations have been found with respect to race, gender, and geographical location, except that the disease has not been reported in Africa, an observation attributed mostly to lack of familiarity and diagnostic tools (Tan*, et al.*, 1993, Barker*, et al.*, 1995, Marciano-Cabral & Cabral, 2003). However, serological evidence suggests that Hispanics are 14.5 times less likely to carry *Acanthamoeba*-reactive antibodies than individuals of other ethnicities (Chappell*, et al.*, 2001, Khan, 2006). A study undertaken to measure the seroprevalence of *Acanthamoeba* in different ethnic groups indicated that up to 90 % of healthy humans can carry *Acanthamoeba* antibodies. Seropositivity occurred in the order of Caucasians, followed by Hispanics and African Americans (Chappell*, et al.*, 2001). But it is unknown whether the occurrence of amoebic encephalitis follows a similar pattern in the general population.
