There is the indication that human deaths as a result of water-borne diseases exceed five million people per year, with over half of the diseases being microbial intestinal infections, especially cholera and diarrhea. A number of pathogenic microorganisms, regarded as water pollution indicators have been observed as the agents of such. These water pollution indicators are present in feces, sewage and can survive as long as pathogenic organisms. These pathogenic microorganisms cause several waterborne infections and diseases like bacterial (cholera, salmonellosis, shigellosis and several diseases associated with pathogenic strains of E. coli), viral (ranging from a mild febrile illness to myocarditis, meningoencephalitis, poliomyelitis, herpangina, hand-foot-and mouth disease and neonatal multi-organ failure), protozoan (cryptosporidiosis, diarrhea encaphilitis, giardiasis, amoebiasis) and fungal (candidiasis, blastomycosis, cryptococcusis, aspergilosis). These biological contaminants that cause several water-borne diseases can however be removed from water through physical (ultraviolet radiation, solar radiation and boiling) and chemical disinfection methods (chlorination, chloramination and ozonation). The aim of this paper was to review the microbial indicators and pathogenic microorganisms in water and wastewater. The paper also discussed the treatment strategies for microbial-contaminated water and wastewaters
