Occurrence of Acanthamoeba spp. in a major river in the Philippines: Impact on water quality and health

Rivers are important freshwater sources. They provide water for domestic and recreational use and serve as ecological sites for various microorganisms. Free-living amoebae are considered naturally occurring organisms in freshwater. However, their prevalence can suggest the water quality at a given source. Forty-five surface water samples from nine different sites were collected from the Marikina River. Samples were processed and cultured in non-nutrient agar (NNA) lawned with Escherichia coli, and were observed for 14 days using a light microscope. Thirty-six (80%) samples yielded a positive amoebic growth. Further molecular testing confirmed the presence of Acanthamoeba spp. using specific primer sets, JDP1 and JDP2. The current results of this study have shown a remarkable jump in the detection rate for free-living amoebae (FLAs). The continued deterioration of the Marikina River due to several human and non-human factors may have been the reason for this phenomenon. River clean-up, resettlement programs, and strict implementation of laws on waste disposal should be considered to rehabilitate the Marikina River. HIGHLIGHTS First report of isolation of Acanthamoeba spp. in the Marikina River.; Water quality assessment through FLA isolation.; First evaluation of health impacts of occurrence of FLAs.; First evaluation of impact on water quality of FLA occurrence.; First data on isolation of FLAs in a river.;