Parasitology is the study of the symbiotic interaction between two different species of organisms in which one (parasite) lives in or on the other (host) and is metabolically dependent upon it. This large field includes the study of community and microbial ecology. Man and animals provide the ecological niches parasites inhabit and other organisms (for example, symbionts) they encounter. There is a need for parasites such as Entamoeba histolytica to be addressed from a biblical perspective that may include their original symbiotic or mutualistic association in man. E. histolytica is a protozoan parasite of the family Entamoebae that is found throughout the world killing approximately 100,000 people per year. Eight amoebas (Endolimax nana, Entamoeba coli, E. histolytica, E. dispar, E. hartmanni, Iodamoeba bütschlii, E. moshkovskii and E. polecki) reside in the human intestinal lumen. In the pre-fallen world there was true ecological harmony with an intimate association of individuals of different species (symbiosis). Creation microbiologists are currently investigating the role of single-celled eukaryotic creatures in the organosubstrate model. While the controlling factors that direct invasiveness of E. histolytica are not well understood, the progression from originally free-living single-celled eukaryotes (neutral or beneficial) toward a pathogenic condition after the Fall could have occurred through a number of mechanisms leading to a parasitic condition.