Objective: Advancements in metagenomic techniques have provided new tools for profiling human parasites in environmental matrices such as wastewater. This study aimed to profile protozoan parasites in wastewater from a major city, rural area, and hospital in Kayseri, Türkiye, using metagenomic techniques.
Materials and Methods: Shotgun metagenome sequencing was conducted on ten water samples collected from five sampling sites over a two-week period. The sequences were aligned to 80 human parasite genomes to evaluate the presence and relative abundance of each parasite species. A comparative bioinformatic analysis was performed on the metagenomes from each sampling point.
Results: The diversity of parasites in the city wastewater exceeded that of the rural and hospital sampling points. Blastocystis spp. subtypes and Giardia intestinalis were dominant in rural wastewater, while Plasmodium falciparum, Plasmodium ovale, Toxoplasma gondii, and Acanthamoeba species showed significant abundance in hospital effluent (p<0.01). Moreover, protozoan parasites not previously reported in a clinical setting were identified in the water samples.
Conclusion: This is the first study in Türkiye investigating the presence of human parasites in wastewater using metagenomics. The study highlights the risk posed by human parasites in treated wastewater to population using natural resources. Implementing a specialized wastewater treatment targeting parasites could mitigate the potential spread of these pathogens in the environment. The study revealed certain sequences associated with species not previously identified in clinical instances. This finding may result from genomic resemblances with other eukaryotic organisms that were not systematically excluded, or alternatively, the displacement of protozoa linked to the increasing influx of refugees.