Monitoring of Noxious Protozoa for Management of Natural Water Resources.

Waterborne parasitic protozoa, particularly and spp., are common causes of diarrhea and gastroenteritis worldwide. The most frequently identified source of infestation is water, and exposure involves either drinking water or recreation in swimming pools or natural bodies of water. In practice, studies on oocysts and cysts in surface water are challenging owing to the low concentrations of these microorganisms because of dilution. In this study, a 3-year monitoring of , and was conducted from August 2014 to June 2016 at 5 surface water sites including 2 lakes, 1 river, and 2 water intake plants. A total of 50 water samples of 40 L were examined. oocysts were detected in 22% of samples and cysts in 32%. Water at the 5 sampling sites was all contaminated with oocysts (0-36/L), cysts (0-39/L), or both. The geometric mean concentrations of and were 1.14 oocysts/L and 4.62 cysts/L, respectively. Thus, effective monitoring plans must take into account the spatial and temporal parameters of contamination because they affect the prevalence and distribution of these protozoan cysts in local water resources.