Waterborne Parasites as Sentinels of Fecal Pollution in the Seven Maar Lakes of San Pablo, Laguna, Philippines: Implications to Public and Ecosystem Health

Author(s): Jeph Roxy Macaraig
Email (s): jmmacaraig1@up.edu.ph
Institution or organization of origin: Parasitology Research Laboratory, Institute of Biological Sciences, University of The Philippines Los Baños
Country: Philippines


The vast ecosystem services and livelihood opportunities offered by the seven maar lakes of San Pablo City in Laguna, Philippines have promoted the expansion of agricultural, aquacultural, residential, and ecotourism areas in the lakes’ vicinities over the years. Realizing the effects of these anthropogenic activities, a comprehensive assessment should be in place to address the gaps in current monitoring efforts. Since the microbial water quality assessment of the lakes is limited to coliforms, this study aimed to determine the extent of contamination of waterborne protozoan parasites in the lakes that may be transmitted to the nearby communities through contaminated waters. A total of 105 surface water samples were collected from the lakes. Results revealed that the lakes were contaminated with various protozoan parasites such as Cryptosporidium sp. (n=32, 30.48%), Blastocystis sp. (n=21, 20%), and Giardia sp. (n=15, 14.29%) that are of both human and animal origin and are usually shed in feces. Moreover, free-living pathogenic amoeba, Acanthamoeba sp. (n=20, 19.05%) was also detected. Interestingly, contamination was high in lakes near residential and agricultural areas where livestock and companion animals are present. Waterborne parasite contamination provides evidence of fecal pollution in the lakes as these organisms enter the aquatic ecosystems when passed in the feces of infected animal and human hosts. It is therefore recommended to improve sanitation and waste management in the lakes’ vicinities, regulation of agricultural activities and residential establishments through land use plans, and to update the traditional monitoring of microbial water quality to include various waterborne parasites.

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