The epidemiology of amebiasis has dramatically changed since the separation of Entamoeba
histolytica and Entamoeba dispar species, and the worldwide prevalence of these species
has not been estimated until recently. The most cited data regarding prevalence, morbidity,
or mortality due to amebiasis is the 1986 Walsh report, in which 100,000 deaths are
reported to occur worldwide each year due to medical complications of invasive amebiasis.
However, the prevalence values of Entamoeba histolytica infection could be completely
erroneous since the estimations were performed prior to the molecular characterization
of E. histolytica and E. dispar species. Moreover, Entamoeba moshkovskii, another
morphologically indistinguishable human parasitic Entamoeba, was not mentioned or
considered as a contributor to the prevalence figures in endemic areas. However, recent
available prevalence and morbidity data obtained through molecular techniques allow
the construction of a more reliable map of endemic regions of amebiasis all over the
world [the Asian subcontinent (India, Bangladesh), Africa, Asian Pacific Countries
(Thailand, Japan), South and Central America (Mexico, Colombia)]. The epidemiology
of infectious diseases focuses on identification of factors that determine disease
distribution in time and space, transmission factors responsible for the disease,
clinical manifestations, and progression in the host, with the goal being the design
of realistic intervention and prevention strategies in a reasonable period of time.
In the present review, we will describe how molecular tools have made actual knowledge
regarding the epidemiology of amebiasis possible. We will also analyze the most relevant
available data on prevalence, morbidity, geographic distribution, patterns of transmission,
exposure, and risk factors for infection in the human host. Our intention is to emphasize
the recent molecular typing methods applied in genotyping Entamoeba species and strains,
and to assess their value and limitations. Finally, we will discuss those areas of
the host-parasite relationship that are still not fully understood, and the scientific
challenges to approach this important public health problem in the future.