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1.
S. Weyl-Feinstein A. Markovics H. Eitam A. Orlov M. Yishay R. Agmon J. Miron I. Izhaki A. Shabtay 《Journal of dairy science》2014
Cryptosporidium parvum is considered one of the most common enteropathogens, responsible for the high incidence of diarrhea and deleterious implications on immunity and health in neonatal calves. The pomegranate is well known for its health-promoting properties. Two experiments were designed to test the antiparasitical and antidiarrheal effects of concentrated pomegranate extract (CPE) supplement in milk in neonatal Holstein calves. Forty-one calves were randomly divided into control (n = 20) and treatment (n = 21) groups. For the first experiment, the treatment group was supplemented with 3.75% CPE in the daily milk ration, between 3 and 14 d of age, whereas the control group received only milk. Fecal samples were collected between d 5 and 13 to quantify Cryptosporidium oocysts, and the duration and intensity of diarrhea were evaluated. Reduced fecal oocyst count and diarrhea intensity and duration were revealed in the 3.75% CPE calves. No difference was noted in average daily gain between groups. In a second experiment, which was designed to test the effect of a lower CPE concentration (0.6% of daily milk allocation), no effects on fecal oocyst count and average daily gain were observed. However, compared with control, the lower CPE group was characterized by a shorter duration of diarrhea and higher weight gain among males at 14 d of age. These results suggest that the CPE supplement-to-calf milk ratio may potentially alleviate intestinal morbidity caused by Cryptosporidium. 相似文献
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The draft Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) contains Cryptosporidium log-inactivation CT tables (ozone-in-water concentration [residual], “C” times contact time, T). Depending on water temperature, Cryptosporidium CT values that are listed are 15 to 25 times greater than CT values for equivalent Giardia log-inactivation credit. The elevated operating dose required for Cryptosporidium log-inactivation credit has the potential to increase disinfection by-product (DBP) formation (e.g., bromate). Calculating CT value accurately will minimize ozone dose, which will decrease operating cost and lower DBP formation, and at the same time maintain disinfection protection through implementation of scientifically based safety factors. Various methods are available for calculating CT value. The method chosen depends largely on the available information concerning ozone residual characteristics and hydrodynamic features of the ozone contactor, plus local regulatory requirements. Four methods are discussed in this paper. Each method can be used to calculate Giardia, virus, and Cryptosporidium log-inactivation credit. 相似文献
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Regulations Introduced in 1999 obliged water companies In England and Wales to conduct risk assessments of their treatment works to establish whether there was a significant risk from Cryptosporidium oocysts in the water supplied. More than 330 treatment works were identified as being at risk, just over half of which were plants treating groundwater. This paper provides an overview of what water companies themselves identified as the most at-risk settings for their groundwater-based works in terms of aquifer and type of supply. Evaluation of results from the subsequent continuous monitoring regulatory regime that came into force on many of these supplies could validate the primarily qualitative nature of the initial assessments of at-risk settings. There would also be public health benefits from confirmation of whether currently-employed risk assessment methods are well-founded because similar procedures could then be applied with confidence to the many small private supplies In Britain. 相似文献
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基于健康风险评价的再生水生物学标准制定方法 总被引:4,自引:0,他引:4
污水再生利用是解决水资源短缺问题的重要措施,制定科学合理的再生水生物学标准是保证其生物安全性的基本措施,但目前我国已有的再生水利用水质标准生物学指标体系不够健全,水质标准的科学依据也不十分明确,有待进一步完善。基于再生水回用的微生物健康风险定量评价方法,根据微生物的剂量-反应关系、暴露剂量计算方法和浓度分布等模型,确定了再生水生物学标准制定方法。以再生水回用于城市绿地灌溉为例,给出了再生水中典型病原微生物隐孢子虫和贾第鞭毛虫浓度限值的确定方法。 相似文献
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There has been no information available on the removal of Cryptosporidium oocysts or oocyst‐sized particles under the sand filtration conditions normally used for swimming pool water treatment. A pilot sand filtration plant has therefore been constructed at The University of Wales Swansea and operated under swimming pool conditions (25 m/h downflow, 30°C, 1.5 mg/L free chlorine, pH 7.3 to 7.5, alkalinity 120–150 mg/L as calcium carbonate). Removal of fluorescent polystyrene particles of a size range (1–7 μm) similar to the size of Cryptosporidium oocysts (about 5 μm) without added coagulant was less than 50%. Removal of the particles under the operating conditions above but with the addition of either of the coagulants polyaluminium chloride (PAC) or aluminium sulphate was capable of giving better than 99% removal of the particles. 相似文献
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In 2000, the UK introduced a Cryptosporidium oocyst monitoring programme for groundwater public supplies as a consequence of a 1999 amendment to statutory water quality regulations in England and Wales. The programme, which is ongoing and was estimated to have cost c. £12 million (€17.4 million) by the end of 2005, has accumulated the largest and most comprehensive array of data on the presence of oocysts in raw groundwater in the UK to date, with 90 water treatment works subjected to continuous monitoring at one time or another between 2000 and 2005. The programme was preceded by a scrutiny of the future of over 180 groundwater supplies identified as significantly at risk by the 19 water utilities concerned. The results of this process and of the monitoring programme up to 2005 are examined and critically reviewed. 相似文献