Examination of Giardia and Cryptosporidium in water samples and fecal specimens in Taiwan

Giardia and Cryptosporidium have emerged as waterborne pathogens of concern over the past few decades. Twenty-nine source water samples were collected from water treatment facilities and checked for the occurrence of Giardia and Cryptosporidium along with some water quality parameters. These facilit ies include ten large-scale treatment plants near major metropolitan areas, and eight simple facilities in small and secluded communities. The indirec t immunofluorescence assay (IFA) was used for the detection of cysts and oo cysts in water samples. In addition, fecal specimens were collected from wa tersheds providing source water for the treatment plants, and the presence of Giardia and Cryptosporidium was detected with the enzyme-linked immunoso rbent assay (EIA). The mean concentrations of protozoa in large-scale plant s were 66.8 cysts/100 litres and 89.2 oocysts/100 litres, while simple faci lities contained 1.27 cysts/100 litres and 0.28 oocysts/100 litres, respect ively. The concentrations of these two parasites exhibit the highest correl ation with turbidity than any other water quality parameters. Among the 101 fecal specimens, eleven were positive for Giardia and 22 were positive for Cryptosporidium. It was also found that the occurrence of these two pathog ens in the source water was directly linked to the surrounding farming acti vities, suggesting that farming activities should be kept at a certain dist ance from the watersheds.