Diagnosis and Epidemiology of Amoebiasis in India

It is now well established that Entamoeba histolytica was indeed a species complex comprising of pathogenic E. histolytica and morphologically indistinguishable non-pathogenic E. dispar and E. moshkovskii. A greater hindrance is the different and inconsistent use of diagnostic methods in different areas of the world. Though microscopy has poor sensitivity, it seems that till today, many epidemiological studies are either based on microscopy alone or PCR assay carried out on microscopy screened samples or PCR assay performed on a very small sample size and thus fails to figure out the true magnitude of amoebiasis. The present review recommends DNA-based systematic approach like rDNA-based DNA dot blot screening followed by PCR assay to determine the true prevalence rate, suggesting its implication in the large-scale epidemiological study. DNA-based studies from across the world showed that the prevalence rate varies from 0.55% to 69.6% among human populations. The studies indicate that various unhygienic practices like unhygienic toilet facilities, poor living conditions, hand washing habits, etc. HIV infection and mutation in LEPR are among common factors that increase the likelihood of amoebiasis. On the other hand, till today it remains unclear if the E. histolytica causing intestinal and extra-intestinal amoebiasis is a similar or different strain.