Comparison of two approaches in detection of Giardia lamblia and Cryptosporidium spp.contamination in various water of urban area
Objective To understand the contamination status with Giardia lamblia and Cryptospordium spp.in different sources of water in urban area of Shanghai,by application of two tests including PCR and fluorescence microscopy.Methods The effluent water samples from water plants were collected from 8 districts and environmental water from 3 districts.The PCR was performed to detect the DNA extracted from the water samples targeting the triosephosphate isomerase(Tim)gene for Giardia spp.and 18S rRNA gene for Cryptosporidium spp.,respectively.The immune-fluorescence microscopy assay(IFA)was performed following Filta-Max Xpress methods based on procedures described in "The National Standard of Detection for Drinking Water(GB5750.12-2006)".The positive rates of detecting contamination with Giardia spp.and Cryptosporidium spp.were compared.Results A total of 200 water samples were collected.No positive sample was found contaminated with Giardia spp.and Cryptosporidium spp.in 48 samples of effluent water from water plants.In water samples,collected from source water of water plant(62 samples),pool water close to animal farms(25 samples),outdoor water of sewage treatment plant(29 samples),swimming pool water(20 samples),and water of fish pond in restaurant(16 samples),the general positive rates of Giardia spp.by PCR was 12.5％with 8.1％,36.0％,17.2％,0 and 0,and the general positive rates of Cryptosporidium spp.by PCR was 11.8％with 6.5％,40.0％,13.8％,0 and 0,in above samples respectively.The general positive rate of Giardia spp.by IFA was 15.1％with 9.7％,40.0％,24.1％,0 and 0,and the general positive rate of Cryptosporidium spp.by IFA was 13.8％with 8.1％,44.0％,17.2％,0 and 0,in above samples respectively.In Kappa test,the identity of two approaches was good with Kappa≧ 0.75(Kappa=0.83 and 0.79).The positive rates of water samples in PCR and IFA had no significantly difference(x2=0.44 and 0.26,P ＜ 0.05).Conclusion The two established approaches,including PCR and IFA,are feasible to be used in epidemiological survey in urban areas.No parasites were detected in the effluent water samples from water plants,but the source water of water plant and environmental water were contaminated with Giardia spp.and Cryptosporidium spp.which need to strengthen the surveillance in future.
NETL
NSTL
万方数据
维普
