Assessment of Methods for Detection of Infectious Cryptosporidium Oocysts and Giardia Cysts in Reclaimed Effluents

Abstract

This study evaluates the occurrence of Cryptosporidium oocysts and Giardia cysts in reclaimed effluents if method 1623 with the Envirochek capsule filters (standard and high-volume [HV] filters) and a modified version of the Information Collection Rule method (ICR) with the polypropylene yarn-wound cartridge filter are used. The recovery efficiency of the analytical methods was evaluated with samples of reagent, tap, and reclaimed water by using flow cytometer-sorted spike suspensions. (Oo)cyst recovery efficiency determined filter performance and method reproducibility in the water matrix tested. Method 1623 with the Envirochek HV capsule filter generated significantly higher recovery rates than did the standard Envirochek filter and the modified ICR method. Notwithstanding, large variations in recovery rates (>80%) occurred with samples of reclaimed water, and none of the water quality parameters analyzed in the reclaimed effluents could explain such variability. The highest concentrations of indigenous oocysts were detected by method 1623 with the HV filter, which provided a sufficient number of oocysts for further confirmation of infectious potential. Confirmation of species and potential infectivity for all positive protozoan samples was made by using a nested PCR restriction fragment polymorphism assay and the focus detection method most-probable-number assay, respectively. The methodology and results described in the present investigation provide useful information for the establishment of pathogen numeric standards for reclaimed effluents used for unrestricted irrigation.Standardized methods used for surface and drinking waters are available to evaluate the occurrence of protozoan pathogens in water supplies, wastewater effluents, and reclaimed effluents. Reclaimed effluents can be defined as those waters that have received a combination of physical, chemical, and biological processes and operations to remove settleable, suspended, and dissolved solids, organic matter, metals, nutrients, and pathogens from wastewater. The major uses of reclaimed effluents include agricultural and landscape irrigation, groundwater recharge, industrial use, and surface water replenishment (2, 16).Cryptosporidium parvum and Giardia lamblia, according to some public health officials, are no more prevalent in reclaimed effluents than in other irrigation waters. Occasional findings of (oo)cysts in reclaimed water may, however, present a health risk due to the potential high viability and various routes of exposure. Public concern about the health risk has prompted many states, including Florida, to add periodic sampling for Giardia and Cryptosporidium to present reuse rules (10).Monitoring for protozoan pathogens is necessary for estimating the risk of infection resulting from exposure to reclaimed water. Presently, there are no approved methods for sampling and detecting protozoan pathogens in reclaimed effluents. With the development of new methods for detecting waterborne Cryptosporidium and Giardia, there is a great intere...

Detection of Infectious Cryptosporidium Oocysts by Cell Culture Immunofluorescence Assay: Applicability to Environmental Samples

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Molecular Characterization of Bubaline Isolate of Cryptosporidium Species from Egypt

“…In Egypt, Cryptosporidium infection was detected in buffalo calves (19.65%) in El Dakahlia Governorate (El-Dessouky and El-Masry, 2005), Middle Egypt (14.19%) (El-Khodery and Osman, 2008), Ismailia (22.5%) (Shoukry et al, 2009), Cairo, Giza, Beni Suef and Qualiobya (52%) (Morsy et al, 2014). Traditionally, the detection of Cryptosporidium oocysts in environmental, water, food, fecal and/or tissue samples had primarily relied on examination by microscopy (O'Donoghue, 1995;Quintero-Betancourt et al, 2003). Oocyst morphology played an important role in Cryptosporidium taxonomy but was inconvenient to clearly differentiate species and genotypes (Fall et al, 2003).…”

Spreading of Bio-wastes onto Soil Surfaces to Control Pathogens: Human Health and Environmental Consequences

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