The prevalence of Giardia and Cryptosporidium in Taiwan water supplies

Giardia and Cryptosporidium have emerged as waterborne pathogens of concern . Thirty-one water samples were collected from nine potable water treatment plants in Taiwan and investigated for the presence of Giardia cysts and Cr yptosporidium oocysts. The immunofluorescence assay was used for the simult aneous detection of cysts and oocysts. The frequency of occurrence of cysts was 77.8% for Giardia and 72.2% for Cryptosporidium in 18 raw water sample s. Ten out of 13 samples collected from treated water samples showed the pr esence of cysts, while in 5 out of 13 treated water samples oocysts were de tected. The risk assessment for adverse human effects arising from the pres ence of cysts and oocysts indicates the possibility of waterborne transmiss ion of Giardia and Cryptosporidium infection in Taiwan if water is not adeq uately treated.