广西宾阳县和灵山县水源隐孢子虫和蓝氏贾第鞭毛虫污染调查

Contamination of Cryptosporidium and Giardia lamblia in water from Binyang County and Lingshan County in Guangxi

目的了解广西壮族自治区宾阳县和灵山县水源中隐孢子虫和蓝氏贾第鞭毛虫(简称贾第虫)的污染情况。方法利用质控标样检验碳酸钙絮凝和膜过滤富集隐孢子虫卵囊、贾第虫包囊的回收率,并与我国的国标方法比较。2016、 2017年6-9月,采集广西壮族自治区宾阳县(自来水厂A、 B、 C、 D和E)和灵山县(自来水厂F、 G、 H、 I和J) 10个自来水厂的进水和出厂水水样,应用碳酸钙絮凝法富集进水中隐孢子虫卵囊和贾第虫包囊,膜过滤法富集出厂水中隐孢子虫卵囊和贾第虫包囊;富集后用磁珠分选和荧光染色检测隐孢子虫卵囊和贾第虫包囊,计算水样中隐孢子虫卵囊和贾第虫包囊的密度。结果碳酸钙絮凝法富集质控标样隐孢子虫卵囊和贾第虫包囊的回收率分别为48.5%和52.0%,膜过滤法为35.0%和36.5%,国标方法为15.0%和16.0%,碳酸钙絮凝法、膜过滤法的回收率均高于我国国标方法,差异具有统计学意义(碳酸钙絮凝法:χ~2=26.007、28.877,均P <0.01;膜过滤法:χ~2=8.167、 11.019,均P <0.01)。10个自来水厂中,每个自来水厂采集进水和出厂水水样各2份。检测结果显示:自来水厂A的进水、 B的进水和出厂水、 C和F的出厂水中检出隐孢子虫卵囊,密度分别为4.0、 10.0、 0.6、 2.9、 5.1个/10 L;自来水厂F的出厂水中检出贾第虫包囊,密度为9.3个/10 L。其余自来水厂的进水和出厂水均未检出隐孢子虫和贾第虫。结论广西壮族自治区宾阳县和灵山县部分自来水厂的进水或出厂水中存在隐孢子虫或贾第虫污染,需加强农村地区饮用水隐孢子虫和贾第虫的监测。

Objective To investigate the contamination of Cryptosporidium and Giardia in water from Binyang County and Lingshan County in Guangxi Zhuang Autonomous Region. Methods Standard quality-control samples were used to compare the recovery rate of Cryptosporidium oocyst and Giardia cyst by calcium carbonate flocculation method and that by membrane filtration, with reference to the National Standard Method. In addition, water samples from 10 tap water suppliers in Binyang (suppliers A, B, C, D and E) and Lingshan (suppliers F, G, H, I and J) counties were collected in 2016 and 2017, including water flowing into and out from the suppliers. Calcium carbonate flocculation method was used to concentrate Cryptosporidium oocysts and Giardia cysts in water flowing into the suppliers, while membrane filtration was used to concentrate Cryptosporidium oocysts and Giardia cysts in water flowing out from the suppliers. Immunomagnetic separation and immunofluorescence staining were then performed to detect the two types of parasites in water, and their densities were calculated. Results The recovery rates of Cryptosporidium oocyst and Giardia cyst in standard quality control samples using calcium carbonate flocculation were 48.5% and 52.0%, respectively, and those by membrane filtration were 35.0% and 36.5%, both performed better than the National Standard Method (15.0% and 16.0%) (calcium carbonate flocculation vs. Standard Method: χ2 = 26.007, 28.877, P < 0.01; membrane filtration vs. Standard Method: χ2 = 8.167, 11.019, P < 0.01). In addition, 10 tap water suppliers were selected, from each of which 2 water samples flowing into and 2 water samples flowing out were collected. The densities of Cryptosporidium oocysts in the water sample flowing into supplier A, water samples flowing into and out from supplier B, and water samples flowing out from suppliers C and F were 4.0/10 L, 10.0/10 L, 0.6/10 L, 2.9/10 L and 5.1/10 L, respectively. The density of Giardia cysts in water sample flowing out from suppliers F was 9.3/10 L. No Cryptosporidium or Giardia was detected in other water samples. Conclusion There are certain contaminations of Cryptosporidium and Giardia in water flowing into or out from water suppliers in Binyang and Lingshan counties. Monitoring on the contamination in rural areas should be strengthened.