Identification of giardia lamblia-specific antigens in infected human and gerbil feces by western immunoblotting

Western immunoblot analysis of aqueous extracts of feces obtained from five giardiasis patients and from experimentally infected gerbils (Meriones unguiculatus) with rabbit antiserum to Giardia lamblia cysts has revealed antigens of three molecular weight groups. A stepladderlike, evenly-spaced set of strongly reactive antigens (darkest at a molecular weight [m.w.] of 55,000 to 70,000) appeared in the gerbil feces from day 4 (first experiment) or day 2 (second experiment) and lasted to about day 7 but disappeared completely by day 8 and did not reappear later. These antigenic bands were seen in gerbils infected with two isolates of G. lamblia. These bands were not revealed when antiserum to trophozoites was used as the probe, nor were they evident in specimens from the patients or in a preparation of sonicated cysts. A second group of antigens, represented by two to three low-m.w. bands of approximately 15,000 to 20,000, was evident in both the blots of gerbil feces after approximately day 8 and the specimens from the giardiasis patients. The third group of antigens revealed by blotting experiments was a high-m.w. band (approximately 110,000) which appeared on a number of days (beginning of day 8 of gerbil infection), but this band was not seen in the human specimens. A clear band corresponding to the previously reported GSA-65 antigen was not seen in either the gerbil or the human samples. Some low- and high-m.w. bands were also detected by antitrophozoite serum in the gerbil samples, but these were weak and unimpressive compared with those visualized using anticyst serum. A monoclonal antibody-based antigen capture enzyme-linked immunosorbent assay revealed that Giardia spp.-specific stool antigen rose suddenly at day 3 of gerbil infection, at the time when fecal cyst numbers began to rise rapidly

Comparison of two methods for detection of Cryptosporidium & Giardia in water

The steps of two immunofluorescent-antibody-based detection methods were evaluated for their efficiencies in detecting Giardia cysts and Cryptosporidium oocysts. The two methods evaluated were the American Society for Testing and Materials proposed test method for Giardia cysts and Cryptosporidium oocysts in low-turbidity water and a procedure employing sampling by membrane filtration, Percoll-Percoll step gradient, and immunofluorescent staining. The membrane filter sampling method was characterized by higher recovery rates in all three types of waters tested: raw surface water, partially treated water from a flocculation basin, and filtered water. Cyst and oocyst recovery efficiencies decreased with increasing water turbidity regardless of the method used. Recoveries of seeded Giardia cysts exceeded those of Cryptosporidium oocysts in all types of water sampled. The sampling step in both methods resulted in the highest loss of seeded cysts and oocysts. Furthermore, much higher recovery efficiencies were obtained when the flotation step was avoided. The membrane filter method, using smaller tubes for flotation, was less time-consuming and cheaper. A serious disadvantage of this method was the lack of confirmation of presumptive cysts and oocysts, leaving the potential for false-positive Giardia and Cryptosporidium counts when cross-reacting algae are present in water samples

LT2 cryptosporidium data: what do they tell us about cryptosporidium in surface water in the United States?

Beginning in 2006 a United States Federal regulation required public water suppliers using surface water serving more than 10,000 population to analyze for Cryptosporidium in at least 24 consecutive monthly samples from each surface water source. In July 2012, the U.S. EPA released the resulting data consisting of ca. 45,000 records. No Cryptosporidium were found in 93% of samples and no Cryptosporidium were found in any samples analyzed from over half of 1670 locations sampled. Nevertheless, at 250 locations representing every region of the U.S., Cryptosporidium were found in sufficient numbers of samples to provide a picture of their occurrence nationwide. Data from about 100 sites reporting the highest numbers were examined in detail. Although analysis of matrix spikes was required for quality control, the results do not permit estimating organism concentrations. The data reported at each of the individual sample locations were analyzed in the form of cumulative probability distributions to describe key risk-related features of median level and variability. Taken as a whole, the data describe a spectrum of median Cryptosporidium occurrence in surface waters of the U.S. ranging from ca. 0.005 to ca. 0.5 oocysts/L. The variability at individual sites ranged from ca. 1 to 15 r.s.d. Based on the LT2 positive data, comparison to measurements of other water quality parameters, and independent means of estimating organism production from watersheds reported in the literature, the hypothesis is offered that Cryptosporidium may be found in surface water anywhere worldwide continuously and within the spectrum defined above

Longitudinal Multiyear Characteristics of Cryptosporidium and Giardia Concentrations in Surface Water: Application to Risk Characterization

The waterborne outbreak potential of Cryptosporidium and Giardia is recognized by public water supply agencies, motivating monitoring of surface sources to meet applicable drinking water regulations. In this study, data from 10 or more years of continuous monitoring at several sites were compiled and analyzed to describe patterns of occurrence and to outline data analysis procedures to better inform watershed management and treatment system management for control of these pathogens. Data were analyzed to identify parameters that enable risk characterization, the median and standard deviation for annual data sets. These values, monitored for a sequence of years, indicate trends related to watershed processes and provide guidance for watershed management. The scope of annual variations, in combination with tracking concentrations corresponding to short-term (seasonal) water quality variations, provides essential information for treatment system management. The patterns of Cryptosporidium and Giardia occurrence over 10 or more years demonstrates their continuous presence in virtually all surface water sources. The results provide a direct means of quantifying risk relative to other years at a single site or to occurrence similarly described elsewhere. Reflection on the results shows that inference of absence from negative findings is no longer acceptable. Clear understanding of the data presented here provide a basis for monitoring that is both more effective and more efficient, providing real value for the substantial investment that monitoring requires. Practical Applications Long-term, 10+-year data for concentrations of Cryptosporidium and Giardia describe their continuous presence and variations over time. Given the high cost of monitoring, a clear understanding of monitoring objective is essential. A continuing record provides a basis for comparing concentration-based risks over time and comparisons with concentrations monitored at other locations. This provides a foundation for watershed management and for treatment system management in relation to risk. The description of monitoring and data analysis principles provides guidance for the development of value-oriented monitoring of these waterborne pathogens and, ultimately, an efficient and effective monitoring program that will satisfy health-based and regulatory monitoring needs

Cryptosporidium and Giardia distribution in water: re-evaluation

The data and the analysis applied to it in a 1996 paper on the statistical distribution of Cryptosporidium in a reservoir arere-examined with the objective of clarifying general understanding of the way in which Cryptosporidium oocysts and Giardia cysts aredistributed in water. General objectives of monitoring for these protozoan parasites are summarized along with essential assumptions usedin statistical analysis. The 1996 analysis is reviewed and an alternative analysis is proposed. The key distinction is that the Poisson modelassumption of a homogeneous population was not appropriate as applied to the data set consisting of 52 consecutive weekly samples, leading to likely misinterpretation of the data. The critical issue is interpretation of negative (zero) results, whether as absence and hence intermittent presence or as continuous presence but below the limit of detection. The alternate analysis shows that the typically skewed annual data set can be effectively described as lognormal. The lognormal distribution of the 1996 data is compared to previously published data on Cryptosporidium and Giardia from reservoirs elsewhere with apparent similarity. The application of the Poisson model to understanding the relation between ambient concentrations of Cryptosporidium and Giardia, sample volumes, and recovery efficiency is described with its importance to effective planning of monitoring and data analysis

ICR SS protozoan data site-by-site: A picture of Cryptosporidium and Giardia in U.S. surface water

ABSTRACT The USEPA Information Collection Rule Supplemental Survey (ICR SS) required analysis of Cryptosporidium and Giardia in 10 L surface water samples twice a week for a year by USEPA Method 1623 at 80 representative USA public water systems (PWS). The resulting data are examined site-by-site in relation to objectives of the Federal drinking water regulation, The Long Term (2) Enhanced Surface Water Treatment Rule, currently under formal 6-year review by the USEPA. The data describe Cryptosporidium and Giardia in watersheds nation-wide over a single annual cycle. Due to limited recovery efficiency measurement results are not fully quantified. In the required sample volumes of 10 L no Cryptosporidium were found in 86% of samples and no Giardia were found in 67% of samples. Yet, organisms were found in enough samples at 34 of 80 sites to detail a specrtum of occurrence and variability for both organisms. The data are shown to describe indivudual site risk essential for guidance of watershed and water treatment management by PWSs. The span of median occurrence for both organisms was about two orders of magnitude above the limit of detection (LD), ca. 0.05 raw no\u27s/L for Cryptosporidium and ca 0.10 raw no\u27s/L for Giardia. Data analysis illustrates key features of Cryptosporidium and Giardia in surface water: presence is continuous not intermittent; zeros indicate presence below the LD; occurrence level and variations depend on watershed sources; risk depends on both magnitude and variability of concentration; accurate estimation of risk requires routine measurement of recovery efficiency and calculation of concentration. The data and analysis illustrate features of Crytpsporidium and Giardia occurrence in surface water relevant to their effective regulation for public health protection

Mathematical And Experimental Investigations Of A Model Of Nitrogen-limited Algal Growth.

PhDSanitationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/190578/2/7415820.pd

Cryptosporidium and Giardia in water: reassessment of occurrence and significance

The current approach in the U.S. water industry for monitoring Cryptosporidium and Giardia has weaknesses that have contributed to the difficulty of interpreting resulting data. This often leads to potentially significant and dangerous misinterpretation. The purpose of this paper is to summarize information on which the conflicting conclusions on the occurrence and distribution of Cryptosporidium and Giardia have been based. Effort is made to determine the most plausible and supportable interpretation. The objective is to provide a basis for rethinking the current approach to monitoring and management of Cryptosporidium and Giardia in water. The importance of measuring recovery efficiency and reporting measurements of these organisms in terms of concentration to any quantitative application is emphasized. Data presentation to illustrate critical features of organism concentration levels and variation is reviewed. Analysis of major data sets resulting from the U.S. Environmental Protection Agency Information Collection Rule Supplemental Survey (USEPA ICR SS) and the Long-Term 2 Enhanced Surface Water Treatment Rule (LT2) monitoring and other previously published relevant data sets is presented to illustrate key features of Cryptosporidium and Giardia occurrence in surface water and their universal geographic distribution. Current thinking emphatically requires revision