密度梯度分离纯化/免疫荧光技术检测饮用水中“两虫”

采用膜溶解、密度梯度分离纯化结合免疫荧光染色法对饮用水中的“两虫”（隐孢子虫和贾第鞭毛虫）进行定性与定量检测，以大幅降低检测成本，简化操作。结果表明，使用Percoll-蔗糖介质可取得良好的分离纯化效果，其卵囊和孢囊初始回收率分别为56％和35％，远高于EPA1623方法的要求。利用该方法对河网型水源水及水厂滤后水进行了检测，发现10L水源水中有1～3个隐孢子虫和0～2个贾第鞭毛虫，但在50L滤后水中均未检出“两虫”。     

密度梯度分离纯化/免疫荧光技检测饮用水中"两虫"

采用膜溶解、密度梯度分离纯化结合免疫荧光染色法对饮用水中的"两虫"(隐孢子虫和贾第鞭毛虫)进行定性与定量检测,以大幅降低检测成本,筒化操作.结果表明,使用Percoll-蔗糖介质可取得良好的分离纯化效果,其卵囊和孢囊初始回收率分别为56%和35%,远高于EPAl623方法的要求.利用该方法对河网型水源水及水厂滤后水进行了检测,发现10 L水源水中有1-3个隐孢子虫和0-2个贾第鞭毛虫,但在50 L滤后水中均未检出"两虫".     

免疫磁分离方法测定水中贾第鞭毛虫和隐孢子虫

贾第鞭毛虫属（Giardia）生物是寄生于人类和动物肠道的有鞭毛的病原生物，隐孢子虫（Cryptosporidium）是寄生于很多生物，包括哺乳生物、鸟类和鱼类胃肠和呼吸道细胞内的球虫，它们通常以孢囊、卵囊的形式存在于水中，当贾第鞭毛虫的孢囊或隐孢子虫的卵囊进入人体消化道后，一般儿童、老人或免疫力低的人易感染，其临床表现为恶心、腹痛、呕吐、腹泻等，严重者甚至死亡。     

上海市浦东自来水厂净水工艺对两虫去除效果的研究

采用免疫磁分离及荧光染色法（EPA1623法）对上海市浦东地区4家自来水厂的原水、出厂水、管网水中贾第鞭毛虫和隐孢子虫的分布状况进行了分析，并考察了水厂净水过程中不同操作单元对两虫的去除效果。研究表明：原水中存在贾第鞭毛虫与隐孢子虫，但其密度分别维持在0～8个／10L和0～6个／10L的低水平，而在出厂水与管网水中均未检出两虫；水厂的混凝、沉淀单元对两虫具有明显的去除效果。     

宠物犬猫贾第鞭毛虫病诊治

贾第鞭毛虫作为一种人畜共患寄生虫,严重危害着宠物犬猫的健康。文章从宠物犬猫贾第鞭毛虫病的感染症状、流行特点、诊断、治疗、预防等几个方面作了论述,指出要重视诊断方法以及药物的选择,尽早建立科学的治疗方案,增加犬猫的抗病能力。     

上海市区原水及自来水中两虫分布调查

对上海市区15座水厂的原水和自来水的调查表明,长江原水及黄浦江上游原水中均有贾第鞭毛虫和隐孢子虫存在,以贾第鞭毛虫为主,原水中两虫的总体污染程度较低;在所有自来水样品中均未发现两虫存在;根据调查结果提出了去除两虫的手段和预警监测方法.     

包头市某牧区小学生隐孢子虫和贾第鞭毛虫感染调查

目的了解内蒙古牧区小学生隐孢子虫和贾第鞭毛虫感染情况,为预防工作提供科学依据。方法选取包头某旗小学牧区学生为对象,利用采样袋采集新鲜粪便,低温保存运至实验室。采用改良抗酸染色检测隐孢子虫,卢戈氏碘液染色检测贾第鞭毛虫。结果共采集小学生粪便样本191份,隐孢子虫总感染率为37. 2%(71/191),男生和女生的感染率分别为40. 0%(44/110)和33. 3%(27/81),差异无统计学意义(χ~2=0. 888,P>0. 05);贾第鞭毛虫总感染率为14. 7%(28/191),男生和女生的感染率分别为14. 5%(16/110)和14. 8%(12/81),差异无统计学意义(χ~2=0. 003,P> 0. 05);隐孢子虫和贾第鞭毛虫混合感染率为5. 8%(11/191),男生和女生的混合感染率分别为7. 3%(8/110)和3. 7%(3/81),差异无统计学意义(χ~2=1. 095,P>0. 05)。结论牧区生源小学生中隐孢子虫和贾第鞭毛虫感染率较高,当地卫生部门应加强卫生宣传和管理。     

澳门地区原水及海水中的病原虫调查

贾第鞭毛虫隐孢子虫是水源性流行病中常见的病原体，通常以孢囊或卵囊的形式存在于水中，常用消毒剂对其消毒效果较差，我国目前尚无饮用水的病原虫标准，有关病原虫在我国饮用水系统中存在情况的调查也未见报道，澳门自来水公司化验研究中心在已完全掌握了病原虫的检测方法后，对澳门地区供水系统及海水水样中的病原虫现状进行了调查，结果显示，在受到污染的原水中有病原虫检出。     

浅谈水环境中隐孢子虫和贾第鞭毛虫的检测方法

水环境中微生物贾第鞭毛虫和隐孢子虫是两种严重危害水质安全的致病性原生寄生虫，主要通过水和食物等传播疾病，人和动物感染“两虫”所患疾病分别称为贾第鞭毛虫病和隐孢子虫病。当前，人们逐渐认识到其对人类的危害不容忽视。因此研究适合我国广大供水企业采用可靠的“两虫”检测方法极其重要，对保障我国城市供水水质安全具有重要的意义。现就“两虫”在水环境中的检测方法予以综述。     

贾第鞭毛虫和隐孢子虫的检测研究

1．1 贾第鞭毛虫的生物特性：贾第鞭毛虫简称贾第虫，简单分为两个生存阶段，一是有繁殖能力的滋养体阶段，一是有环境抗性的包囊阶段。一旦包囊被易感宿主摄取，包囊在胃酸和酶或其它未确定的消化剂的作用下发生脱囊。脱囊后，形成的滋养体离开囊壁快速进行二元胞质分裂形成两个子代滋养体。当其沿肠道移动时，由于胆汁、碱性pH或细菌代谢物的影响，滋养体形成包囊。     

Prevalence of Cryptosporidium oocysts and giardia cysts in the drinking water supply in Japan

A one-year monitoring of Cryptosporidium oocysts and Giardia cysts was conducted at a water purification plant. A total of 13 samples of 50 L river source water and 26 samples of 2,000 L-filtered water, treated by coagulation flocculation, sedimentation and rapid filtration, were tested. Prior to conducting a survey of a water purification plant, we developed a method for concentrating Cryptosporidium oocysts from a large volume of raw or filtered water using a hollow fiber ultrafiltration (UF) membrane, and this procedure was adapted to survey a water purification plant. Cryptosporidium oocysts were detected in all of the 13 raw water samples. The geometric mean concentration was 40 oocysts 100 L. Giardia cysts were detected in 12 of 13 raw water samples (92%) and the geometric mean concentration was 17 cysts/100 L. Probability distributions of both Cryptosporidium oocyst and Giardia cyst concentration in raw water were nearly lognormal. In filtered water samples, Cryptosporidium oocysts were detected in 9 of the 26 samples (35%) with the geometric mean concentration of 1.2 oocysts /1,000 L and Giardia cysts in 3 samples (12%) with 0.8 cysts/1,000 L. The estimated log10 removal efficiency of Cryptosporidium oocysts and Giardia cysts by rapid-sand filtration was 2.47 and 2.53, respectively. Empty particles were removed at a higher log10 than intact oocysts and cysts. The efficiency of particle removal in the rapid sand filtration process tends to be reduced under cold-water conditions. Close management is necessary in the winter when the water temperature is low.     

Influence of land use and watershed characteristics on protozoa contamination in a potential drinking water resources reservoir

Relative changes in the microbial quality of Lake Texoma, on the border of Texas and Oklahoma, were investigated by monitoring protozoan pathogens, fecal indicators, and factors influencing the intensity of the microbiological contamination of surface water reservoirs. The watershed serves rural agricultural communities active in cattle ranching, recreation, and is a potential drinking water source. A total of 193 surface water samples were tested over a 27-month period to determine levels of parasite contamination. The overall occurrence of Cryptosporidium oocysts was higher in both frequency and concentration than Giardia cysts. Cryptosporidium oocysts were found in 99% and Giardia cysts in 87% of the samples. Although Cryptosporidium and Giardia occurrence were significantly but not strongly correlated, all other correlation coefficients including turbidity and total dissolved solids were non-significant. Statistically supportable seasonal variations were found suggesting that Cryptosporidium and Giardia were higher in summer and fall than in other seasons of the year. While Cryptosporidium levels were correlated with rainfall, this was not the case with Giardia. The maximum numbers for both protozoan parasites were detected from a site impacted by cattle ranching during calving season. Restriction fragment length polymorphism analysis was used for confirmation of Cryptosporidium in surface waters influenced by agricultural discharges. As we had expected, oocysts were of the bovine type indicating that the Cryptosporidium parvum detected in surface waters perhaps came from cattle living in the watershed.     

再生水中隐孢子虫和贾第鞭毛虫的检测方法研究

隐孢子虫和贾第鞭毛虫（简称“两虫”）是两种严重危害水质安全的病原性原生动物,但国际上常用的两虫检测方法——1623方法存在工作量大、成本高、回收率低等缺点。通过考察1623方法中浓缩、分离两个主要环节的替代方案,发现膜过滤—洗脱是比较理想的两虫浓缩方式,在免疫磁性分离（IMS）环节中酸解离比热解离的效果好。根据以上研究成果,建立了回收率较高（对两虫的回收率分别超过了30％和40％）而成本较低（为原方法的55％左右）的再生水两虫密度检测方法。进一步的研究表明,浓缩是限制低浊水（浊度约1NTU）回收率的主要步骤,而IMS是限制高浊水（浊度约4NTU）回收率的主要步骤。     

The Occurrence and Viability of Giardia Cysts in Scottish Raw and Final Waters

The occurrence of Giardia cysts in Scottish raw and potable waters was investigated. Giardia cysts were detected in 49% of raw waters, with concentrations of up to 1.05 cysts per litre, and in 19% of final waters, with concentrations of up to 1.67 cysts per litre. In some of the positive water samples the viability of the cysts was assessed by viewing the cyst morphology and inclusion/exclusion of propidium iodide. Viable cysts were detected in a proportion of both raw waters and positive final waters studied. Further investigations at 21 water-treatment plants revealed cysts in 9 (43%) of the raw waters, and in 4 (19%) of the final waters. Cysts were only detected in the final waters of plants in which cysts were also detected in the raw water. These data indicate that viable Giardia cysts may be ingested with potable water in Scotland.     

The persistence and removal of enteric pathogens in constructed wetlands

Sedimentation is thought to be one of the mechanisms of microbial reduction from wetlands used for wastewater treatment. This study compared the occurrence and survival of enteric indicator microorganisms and pathogens in the water column and sediments of two constructed surface flow wetlands in Arizona. On a volume/wet weight basis the concentration of fecal coliforms and coliphage in the water column and sediment was similar. However, on a volume/dry weight basis the numbers were one to two orders of magnitude higher in the sediment. Giardia cyst and Cryptosporidium oocyst concentrations were one to three orders of magnitude greater in the sediment compared to the water column. The die-off rates of all the bacteria and coliphage were greater in the water column than the sediment. The die-off rates of fecal coliforms in the water and sediment were 0.256log(10)day(-1) and 0.151log(10)day(-1), respectively. The die-off rates of Salmonella typhimurium in the water and sediment were 0.345log(10)day(-1) and 0.312log(10)day(-1), respectively. The die-off rates of naturally occurring coliphage in water column and sediment were 0.397log(10)day(-1) and 0.107log(10)day(-1), respectively, and the die-off rates of and PRD-1 in water and sediment were 0.198log(10)day(-1) and 0.054log(10)day(-1), respectively. In contrast Giardia die-off in the sediment was greater compared to the water column. The die-off rates of Giardia in water and sediment were 0.029log(10)day(-1) and 0.37log(10)day(-1), respectively. Coliphage survived the longest of any group of organisms in the sediment and the least in the water column. In contrast Giardia survived best in the water column and least in the sediment.     

某市贾第鞭毛虫和隐孢子虫污染现状

利用免疫荧光分析技术对南方某市饮用水源水、自来水厂出水和污水处理厂进、出水中贾第鞭毛虫和隐孢子虫(两虫)的污染状况进行了调查,并就自来水厂常规处理工艺对两虫的去除特性进行了研究.结果显示:该市饮用水源水中的两虫密度分别为2～120个/100L和0～24个/100 L,自来水厂出水分别为0～12个/1000 L和0～8个/1000 L,污水处理厂进水中的两虫密度分别为7 200～18 300个/L和69～1 210个/L,二级处理出水的分别为6～153个/L和1～46个/L;混凝沉淀和过滤对两虫有较好的去除效果.     

Monitoring of Cryptosporidium and Giardia river contamination in Paris area

This study evaluates the protozoan contamination of river waters, which are used for drinking water in Paris and its surrounding area (about 615,000 m(3) per day in total, including 300,000 m(3) for Paris area). Twenty litre samples of Seine and Marne Rivers were collected over 30 months and analyzed for Cryptosporidium oocysts and Giardia cysts detection according to standard national or international methods. Cryptosporidium oocysts and Giardia cysts were found, respectively, in 45.7% and 93.8% of a total of 162 river samples, with occasional high concentration peaks. A significant seasonal pattern was observed, with positive samples for Cryptosporidium more frequent in autumn than spring, summer and winter, and positive samples for Giardia less frequent in summer. Counts of enterococci and rainfalls were significantly associated with Giardia concentration but not Cryptosporidium. Other faecal bacteria were not correlated with monitored protozoan. Marne seems to contribute mainly to the parasitic contamination observed in Seine. Based on seasonal pattern and rainfall correlation, we hypothesize that the origin of contamination is agricultural practices and possible dysfunction of sewage treatment plants during periods of heavy rainfalls. High concentrations of protozoa found at the entry of drinking water plants justify the use of efficient water treatment methods. Treatment performances must be regularly monitored to ensure efficient disinfection according to the French regulations.     

Detection of enteric viruses, Giardia and Cryptosporidium in two different types of drinking water treatment facilities

In this study, two types of drinking water treatment facilities (two conventional drinking water treatment plants (DWTPs) and two compact units (Cus)) were compared referring to their production capacity. Water samples were collected from three main points: (a) different water treatment steps (b) washings of sand filters and (c) distribution system at different distances from the water treatment plants. Both viruses and protozoa were concentrated from each water sample by adsorption and accumulation on the same nitrocellulose membrane filters (0.45 microm pore size). Enteroviruses were detected by plaque infectivity assay in BGM cells and HAV, HEV and Norovirus were detected by RT-PCR. Giardia and Cryptosporidium were detected by conventional staining methods and PCR. The results revealed that enterovirus load at the intake ranged between 10-15 PFU/L for the two compact units and between 4.5 and 75 PFU/L for the two conventional DWTPs. The virus load in distribution system of the first type DWTPs at 1 km from the plant was the same as that of the intake. Viruses in the other type of treatment plants CUs at 1, 5 and 7 km, were much reduced. Investigation of raw water sediments of the two DWTPs showed enterovirus counts between 12 and 17.5 PFU/L. Virus count was reduced in sand of filters after washing. Giardia cysts were equally detected by microscopy and PCR in only intake samples of EL-Hawamdia CU (33.3%) and Meet Fares DWTP (50%). Cryptosporidium oocysts were equally detected by microscopy and PCR in intake samples of Abo EL-Nomros CU (100%), EL-Hawamdia CU (66.7%) and Fowa DWTP (50%). At Meet Fares DWTP three positive intake samples for Cryptosporidium were detected by PCR, compared with only two positive samples by microscopy. Giardia cysts and Cryptosporidium oocysts were detected in raw water sediment and sand of filters before washing. Only one sample from Meet Fares DWTP sand of filters after washing was positive for both Giardia and Cryptosporidium. It can be concluded that the poor microbial quality of the water may be due to improper operational skills and management of the various water treatment plants (especially at the two high capacity treatment plants).