Table 1.

Occurrence of Cryptosporidium and Giardia spp. in source and tap water samples in Shanghai, China

Water sample and detection technique	Cryptosporidium				Giardia
	Filtration		CCF		Filtration		CCF
	Detectiona	Intensity (mean ± SD)b	Detection	Intensity (mean ± SD)	Detection	Intensity (mean ± SD)	Detection	Intensity (mean ± SD)
Source water
Microscopy	16/50c	5.2 ± 6.5	11/50c	4.5 ± 4.3	9/50d	3.8 ± 2.1	5/50d	2.2 ± 0.5
PCR	6/50	1.8 ± 0.8	14/50	2.1 ± 1.2	NDe		ND
Tap water and microscopy	2/30	0.2 ± 0.0	ND		0		ND

^aNumber of samples positive for Cryptosporidium or Giardia/number of samples analyzed.

^bFor microscopy, the intensity is the calculated concentration of Cryptosporidium oocysts or Giardia cysts for 10 liters of water is shown. For PCR, the intensity is the number of PCR-positive replicates/5 replicates for all positive samples.

^cEight samples were positive for Cryptosporidium by both methods.

^dNo sample was positive for Giardia by both methods.

^eND, not done.