Abstract The current study presents a comprehensive review of worldwide waterborne parasitic protozoan outbreaks reported between 2017 and 2022. Totally, 416 were attributed to transmission protozoa. Cryptosporidium was the etiological agent in 77.4% (322) outbreaks, while Giardia 17.1% (71). Toxoplasma gondii Naegleria fowleri causal 1.4% (6), 1% (4) respectively. Each Blastocystis hominis, Cy...