Abstract: 【Abstract】   Objective   To understand the contamination status of Cryptosporidium sp. and Giardia lamblia in drinking water, source water and environmental water in Shanghai.  Methods   All water samples collected from drinking water, source water and environmental water were detected by a procedure of micromembrane filtration, immune magnetic separation（IMS）, and immunofluorescent assay（IFA）.   Results   Cryptosporidium oocysts and Giardia cysts were not found in 156 samples of the drinking water including finished water, tap water, or pipe water for directly drinking in communities. Among 70 samples either source water of water plants（15 samples）, environmental water from Huangpu River（25）, canal water around animal sheds（15）, exit water from waste-water treatment plants（9）, or waste water due to daily life（6）, Cryptosporidium oocysts were detected in 1（6.7%）, 2（8.0%）, 7（46.7%）, 1（11.1%）, and 1（16.7%） samples, respectively; and Giardia cysts were detected in 1（6.7%）, 3（12.0%）, 6 （40.0%）, 2（22.2%）, and 2（33.3%）, respectively. The positive rate of  Cryptosporidium oocysts and Giardia cysts was 17.1%（12/70） and 20.0%（14/70）, respectively.   Conclusion   No Cryptosporidium oocysts and Giardia cysts have been detected in drinking water, but found in source water and environmental water samples in Shanghai.

Key words: Cryptosporidium, Giardia lamblia, Drinking water, Source water, Environmental water, Contamination