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Journal Articles
Treatment
of MTBE using Fenton's Reagent
EPA/600/JA-00/193
2000
This paper addresses the removal of MTBE from water, using Fenton's Reagent. Although complete mineralization of MTBE by Fenton’s Reagent was not achieved, greater than 99% destruction of MTBE was realized. This was accomplished at a Fe+2:H2O2 ratio of 1:1 and one hour of contact time. In all tests, twice the stoichiometric ratio of H2O2 to MTBE was used. The major byproducts were tertiary butyl alcohol, tertiary butyl formate, and acetone with traces of 2-methyl-1-propene (isobutene). While small quantities of O2 evolved, no significant quantity of CO2 gas was detected...Continue Reading.
EPA/600/JA-00/193
2000
This paper addresses the removal of MTBE from water, using Fenton's Reagent. Although complete mineralization of MTBE by Fenton’s Reagent was not achieved, greater than 99% destruction of MTBE was realized. This was accomplished at a Fe+2:H2O2 ratio of 1:1 and one hour of contact time. In all tests, twice the stoichiometric ratio of H2O2 to MTBE was used. The major byproducts were tertiary butyl alcohol, tertiary butyl formate, and acetone with traces of 2-methyl-1-propene (isobutene). While small quantities of O2 evolved, no significant quantity of CO2 gas was detected...Continue Reading.
Identification
of Species and Sources of Cryptosporidium Oocysts in Storm Waters with
a Small-Subunit rRNA-Based Diagnostic and Genotyping Tool 
EPA/600/J-00/321
The identification of Cryptosporidium oocysts in environmental samples is largely made by the use of an immunofluorescent assay. In this study, we have used a small-subunit rRNA-based PCR-restriction fragment length polymorphism technique to identify species and sources of Cryptosporidium oocysts present in 29 storm water samples collected from a stream in New York. A total of 12 genotypes were found in 27 positive samples; for 4 the species and probable origins were identified by sequence analysis, whereas the rest represent new genotypes from wildlife. Thus, this technique provides an alternative method for the detection and differentiation of Cryptosporidium parasites in environmental samples...Continue Reading.
EPA/600/J-00/321
The identification of Cryptosporidium oocysts in environmental samples is largely made by the use of an immunofluorescent assay. In this study, we have used a small-subunit rRNA-based PCR-restriction fragment length polymorphism technique to identify species and sources of Cryptosporidium oocysts present in 29 storm water samples collected from a stream in New York. A total of 12 genotypes were found in 27 positive samples; for 4 the species and probable origins were identified by sequence analysis, whereas the rest represent new genotypes from wildlife. Thus, this technique provides an alternative method for the detection and differentiation of Cryptosporidium parasites in environmental samples...Continue Reading.
Get
Real!
EPA/600/JA-01/027
2001
Combined sewer overflow (CSO) is a significant source of pollution in receiving waters. However, implementing a real-time control scheme operates automatic regulators more efficiently to maximize a collection system's storage, treatment, and transport capacities, reducing the volume and number of CSOs. Real-time control schemes are being used to manage complex urban collection systems around the world, including a demonstration study in Canada for the Quebec Urban Community (QUC) collection system. Funded by the U.S. EPA (under a contract to the ORD) to assess the use of real-time control schemes, the QUC study evaluated the effectiveness of three schemes in managing CSOs...Continue Reading.
EPA/600/JA-01/027
2001
Combined sewer overflow (CSO) is a significant source of pollution in receiving waters. However, implementing a real-time control scheme operates automatic regulators more efficiently to maximize a collection system's storage, treatment, and transport capacities, reducing the volume and number of CSOs. Real-time control schemes are being used to manage complex urban collection systems around the world, including a demonstration study in Canada for the Quebec Urban Community (QUC) collection system. Funded by the U.S. EPA (under a contract to the ORD) to assess the use of real-time control schemes, the QUC study evaluated the effectiveness of three schemes in managing CSOs...Continue Reading.
Sewer
and Tank Flushing for Corrosion and Pollution Control
EPA/600/J-01/120
This paper presents an overview of causes of sewer deterioration together with a discussion of control methods that can prevent or arrest this deterioration. In particular, the paper covers inline- and combined sewer overflow- (CSO) storage-tank-flushing systems for removal of sediments and minimizing hydrogen sulfide production resulting in the reduction of associated pollution and sewerline corrosion. During low-flow dry-weather periods, sanitary wastewater solids deposited in combined sewer systems can generate hydrogen sulfide and methane gases due to anaerobic conditions. Sulfates are reduced to hydrogen sulfide gas that can then be oxidized to sulfuric acid on pipes and structure walls by further biochemical transformation. Furthermore, these solids deposits or sediments are discharged to the urban streams during storm events which can cause degradation of receiving-water quality. Thus, dry-weather sewer sedimentation not only creates hazardous conditions and sewer degradation but contributes significant pollutant loads to the urban receiving waters during wet-weather high-flow periods...Continue Reading.
EPA/600/J-01/120
This paper presents an overview of causes of sewer deterioration together with a discussion of control methods that can prevent or arrest this deterioration. In particular, the paper covers inline- and combined sewer overflow- (CSO) storage-tank-flushing systems for removal of sediments and minimizing hydrogen sulfide production resulting in the reduction of associated pollution and sewerline corrosion. During low-flow dry-weather periods, sanitary wastewater solids deposited in combined sewer systems can generate hydrogen sulfide and methane gases due to anaerobic conditions. Sulfates are reduced to hydrogen sulfide gas that can then be oxidized to sulfuric acid on pipes and structure walls by further biochemical transformation. Furthermore, these solids deposits or sediments are discharged to the urban streams during storm events which can cause degradation of receiving-water quality. Thus, dry-weather sewer sedimentation not only creates hazardous conditions and sewer degradation but contributes significant pollutant loads to the urban receiving waters during wet-weather high-flow periods...Continue Reading.
Phylogenetic
Analysis of Cryptosporidium Parasites Based on the Small Subunit Ribosomal
RNA Gene Locus
EPA/600/J-01/123
Biological data support the hypothesis that there are multiple species in the genus Cryptosporidium, but a recent analysis of the available genetic data suggested that there is insufficient evidence for species differentiation. In order to resolve the controversy in the taxonomy of this parasite genus, we characterized the small-subunit rRNA genes of Cryptosporidium parvum, Cryptosporidium baileyi, Cryptosporidium muris, and Cryptosporidium serpentis and performed a phylogenetic analysis of the genus Cryptosporidium. Our study revealed that the genus Cryptosporidium contains the phylogenetically distinct species C. parvum, C. muris, C. baileyi, and C. serpentis, which is consistent with the biological characteristics and host specificity data...Continue Reading.
EPA/600/J-01/123
Biological data support the hypothesis that there are multiple species in the genus Cryptosporidium, but a recent analysis of the available genetic data suggested that there is insufficient evidence for species differentiation. In order to resolve the controversy in the taxonomy of this parasite genus, we characterized the small-subunit rRNA genes of Cryptosporidium parvum, Cryptosporidium baileyi, Cryptosporidium muris, and Cryptosporidium serpentis and performed a phylogenetic analysis of the genus Cryptosporidium. Our study revealed that the genus Cryptosporidium contains the phylogenetically distinct species C. parvum, C. muris, C. baileyi, and C. serpentis, which is consistent with the biological characteristics and host specificity data...Continue Reading.
Urban
Wet-Weather Flows Literature Review 2000
EPA/600/JA-01/307
2001
This paper is an urban wet weather flow (WWF) literature reviews for the year of 1999. The reviews were originally published in the annual literature review issues of Water Environment Research. Over the past year, many people were involved in preparing these urban wet weather flow reviews, many associated with the EPA’s Wet-Weather Flow Research Program. The field of urban Urban Watershed Management Research has expanded dramatically, likely due to increased interest in the US due to the NPDES stormwater permit program, plus increased awareness of the seriousness of urban WWFs throughout the world. About 1000 references are included in this review, indicating the magnitude of interest in this topic. In addition, the large number of specialized stormwater conferences that are now scheduled each year, plus the increasing number of nonpoint sessions at large international conferences...Continue Reading.
EPA/600/JA-01/307
2001
This paper is an urban wet weather flow (WWF) literature reviews for the year of 1999. The reviews were originally published in the annual literature review issues of Water Environment Research. Over the past year, many people were involved in preparing these urban wet weather flow reviews, many associated with the EPA’s Wet-Weather Flow Research Program. The field of urban Urban Watershed Management Research has expanded dramatically, likely due to increased interest in the US due to the NPDES stormwater permit program, plus increased awareness of the seriousness of urban WWFs throughout the world. About 1000 references are included in this review, indicating the magnitude of interest in this topic. In addition, the large number of specialized stormwater conferences that are now scheduled each year, plus the increasing number of nonpoint sessions at large international conferences...Continue Reading.
Wastewater
Collection System Infrastructure Research Needs
EPA/600/JA-02/226
2002
Many of the wastewater collection systems in this country were developed in the early part of this century. Maintenance, retrofits, and rehabilitations since then have resulted in patchwork systems consisting of technologies from different eras. More advanced and cost-effective methods to properly rehabilitate these systems must be considered to guarantee sustainability into the future. Achieving sustainable development presents a challenge to deliver new and innovative infrastructure and facilities needed to serve society while protecting the environment. In the context of this paper, sustainable development would provide new and improved solutions to existing and emerging problems associated with wastewater collection system infrastructure. Such solutions would, for example, include consideration of innovative approaches and practices for identifying and rehabilitating problems in existing systems and ways of preventing these problems in new construction...Continue Reading.
EPA/600/JA-02/226
2002
Many of the wastewater collection systems in this country were developed in the early part of this century. Maintenance, retrofits, and rehabilitations since then have resulted in patchwork systems consisting of technologies from different eras. More advanced and cost-effective methods to properly rehabilitate these systems must be considered to guarantee sustainability into the future. Achieving sustainable development presents a challenge to deliver new and innovative infrastructure and facilities needed to serve society while protecting the environment. In the context of this paper, sustainable development would provide new and improved solutions to existing and emerging problems associated with wastewater collection system infrastructure. Such solutions would, for example, include consideration of innovative approaches and practices for identifying and rehabilitating problems in existing systems and ways of preventing these problems in new construction...Continue Reading.
Suspension
Culture and Plant Regeneration of Typha latifolia
EPA/600/JA-02/227
2002
This study is the first reported attempt to generate a growth curve from Typha latifolia L. (broadleaf cattail) callus cells in suspension culture. Several media and hormone combinations were tested for their capacity to induce callus cell formation from T. latifolia leaf sections and both male and female inflorescence spikes. A. T. latifolia callus cell line was successfully established from immature female inflorescence spikes. Callus growth on Gamborgs B5 medium supplemented with 5 mg/L(-1) dicamba and 1 mg/L(-1) BA was superior to other media examined. A growth curve in suspension culture was generated on the most favorable culture medium for callus growth. The mass of the cells increased by 150% by the end of the growth curve. Researchers have reported that this species can remove pollutants from stormwater wetlands very effectively...Continue Reading.
EPA/600/JA-02/227
2002
This study is the first reported attempt to generate a growth curve from Typha latifolia L. (broadleaf cattail) callus cells in suspension culture. Several media and hormone combinations were tested for their capacity to induce callus cell formation from T. latifolia leaf sections and both male and female inflorescence spikes. A. T. latifolia callus cell line was successfully established from immature female inflorescence spikes. Callus growth on Gamborgs B5 medium supplemented with 5 mg/L(-1) dicamba and 1 mg/L(-1) BA was superior to other media examined. A growth curve in suspension culture was generated on the most favorable culture medium for callus growth. The mass of the cells increased by 150% by the end of the growth curve. Researchers have reported that this species can remove pollutants from stormwater wetlands very effectively...Continue Reading.
Cost
for Water Supply Distribution System Rehabilitation
EPA/600/JA-02/406
2002
A major challenge for the society in the twenty-first century will be design, rehabilitation, replacement, and optimal management of drinking water distribution systems. A recent survey conducted by the USEPA found that $138B will be needed to maintain and replace existing drinking water systems over the next 20 years. It is estimated that $77B of this expenditure will be dedicated to repairing and rehabilitating pipelines. Given the cost and disruption caused by replacing distribution system pipe using conventional open trench technology, utilities are beginning to increase the application of rehabilitation or trenchless replacement technologies to extend the life of existing pipes. This paper presents cost models and representative costs that can be used by utility managers to estimate rehabilitation and replacement costs for distribution system pipelines. It should be noted that these cost models and representative costs are intended to be used for comparing costs between various rehabilitation/replacement technologies and not for construction cost estimates...Continue Reading.
EPA/600/JA-02/406
2002
A major challenge for the society in the twenty-first century will be design, rehabilitation, replacement, and optimal management of drinking water distribution systems. A recent survey conducted by the USEPA found that $138B will be needed to maintain and replace existing drinking water systems over the next 20 years. It is estimated that $77B of this expenditure will be dedicated to repairing and rehabilitating pipelines. Given the cost and disruption caused by replacing distribution system pipe using conventional open trench technology, utilities are beginning to increase the application of rehabilitation or trenchless replacement technologies to extend the life of existing pipes. This paper presents cost models and representative costs that can be used by utility managers to estimate rehabilitation and replacement costs for distribution system pipelines. It should be noted that these cost models and representative costs are intended to be used for comparing costs between various rehabilitation/replacement technologies and not for construction cost estimates...Continue Reading.
Treatment
of Methyl Tertiary-Butyl Ether (MTBE)-Contaminated Waters with Fenton's
Reagent
EPA/600/JA-03/117
2003
Methyl tertiary-butyl ether (MTBE) has been commonly used as a fuel additive because of its many favorable properties that allow it to improve fuel combustion and reduce resulting concentrations of carbon monoxide and unburnt hydrocarbons. Unfortunately, increased production and use have led to its introduction into the environment. Of particular concern is its introduction into drinking water supplies. Accordingly, research studies have been initiated to investigate the treatment of MTBE-contaminated soil and water. In this study, experiments were conducted to demonstrate the effectiveness of Fenton=s reagent (H2O2:Fe+2) to treat MTBE- contaminated groundwater. The concentration of MTBE was reduced from an initial concentration of 1,300 mg/L (14.77 m moles) to the regulatory level of 20 mg/L (0.23 F moles) at a H2O2:Fe+2 molar ratio of 1:1, with 10 minutes of contact time and an optimum pH of 5. The byproducts, acetone and tertiary butyl alcohol, always present in MTBE in trace amounts, were not removed even after 60 minutes of reaction time...Continue Reading.
EPA/600/JA-03/117
2003
Methyl tertiary-butyl ether (MTBE) has been commonly used as a fuel additive because of its many favorable properties that allow it to improve fuel combustion and reduce resulting concentrations of carbon monoxide and unburnt hydrocarbons. Unfortunately, increased production and use have led to its introduction into the environment. Of particular concern is its introduction into drinking water supplies. Accordingly, research studies have been initiated to investigate the treatment of MTBE-contaminated soil and water. In this study, experiments were conducted to demonstrate the effectiveness of Fenton=s reagent (H2O2:Fe+2) to treat MTBE- contaminated groundwater. The concentration of MTBE was reduced from an initial concentration of 1,300 mg/L (14.77 m moles) to the regulatory level of 20 mg/L (0.23 F moles) at a H2O2:Fe+2 molar ratio of 1:1, with 10 minutes of contact time and an optimum pH of 5. The byproducts, acetone and tertiary butyl alcohol, always present in MTBE in trace amounts, were not removed even after 60 minutes of reaction time...Continue Reading.
Sewer
Sediment Control: Overview of an EPA Wet-Weather Flow Research Program
EPA/600/J-03/188
This paper presents a historical overview of the sewer sediment control projects conducted by the Wet-Weather Flow Research Program of the U. S. Environmental Protection Agency. Research presented includes studies of the causes of sewer solids deposition and development/evaluation of control methods that can prevent sewer-sediment accumulation. Discussions focus on the relationship of wastewater characteristics to flow-carrying velocity, abatement of solids deposition and solids resuspension in sewers, and sewerline flushing systems for removal of sewer sediment. Methods for abating sewer sedimentation include steeper sewer slopeage, pipe bottom shapes that maintain high velocity during low-flow conditions, and periodic sewer flushing. The future research program plan for sewer-sediment control is also presented...Continue Reading.
EPA/600/J-03/188
This paper presents a historical overview of the sewer sediment control projects conducted by the Wet-Weather Flow Research Program of the U. S. Environmental Protection Agency. Research presented includes studies of the causes of sewer solids deposition and development/evaluation of control methods that can prevent sewer-sediment accumulation. Discussions focus on the relationship of wastewater characteristics to flow-carrying velocity, abatement of solids deposition and solids resuspension in sewers, and sewerline flushing systems for removal of sewer sediment. Methods for abating sewer sedimentation include steeper sewer slopeage, pipe bottom shapes that maintain high velocity during low-flow conditions, and periodic sewer flushing. The future research program plan for sewer-sediment control is also presented...Continue Reading.
Costs
of Best Management Practices and Associated Land for Urban Stormwater
Control
EPA/600/JA-03/261
2003
The purpose of this paper is to present information on the cost of stormwater pollution control facilities in urban areas, including collection, control, and treatment systems. Information on prior cost studies of control technologies and cost estimating models used in these studies was collected, reviewed, and evaluated. The collection phase involved identifying, screening, and consolidating publications associated with capital costs of stormwater conveyance systems and control technologies. The resulting data were evaluated to develop a critical review of costs for urban stormwater control technologies, including identification of cost information gaps and research needs...Continue Reading.
EPA/600/JA-03/261
2003
The purpose of this paper is to present information on the cost of stormwater pollution control facilities in urban areas, including collection, control, and treatment systems. Information on prior cost studies of control technologies and cost estimating models used in these studies was collected, reviewed, and evaluated. The collection phase involved identifying, screening, and consolidating publications associated with capital costs of stormwater conveyance systems and control technologies. The resulting data were evaluated to develop a critical review of costs for urban stormwater control technologies, including identification of cost information gaps and research needs...Continue Reading.
Particle-Associated
Microorganisms in Stormwater Runoff
EPA/600/J-03/262
This research investigated the effects of blending and chemical addition before analysis of the concentration of microorganisms in stormwater runoff from a single summer storm to determine whether clumped or particle-associated organisms play a significant role. The standard membrane filtration method was used to enumerate the microorganisms. All organisms, except for Escherichia coli, showed an increase in the measured concentration after blending samples at 22,000 rpm with or without the chemical mixture. Other than fecal streptococci, the organism concentrations decreased with the addition of the Camper's solution in both blended and unblended samples before analyses. There was a statistically significant interaction between the effects of Camper's solution and the effects of blending for all the organisms tested, except for total coliform. Blending did not alter the mean particle size significantly. The results show no correlation between increased total coliform, fecal coliform, and fecal streptococcus concentrations and the mean particle size...Continue Reading.
EPA/600/J-03/262
This research investigated the effects of blending and chemical addition before analysis of the concentration of microorganisms in stormwater runoff from a single summer storm to determine whether clumped or particle-associated organisms play a significant role. The standard membrane filtration method was used to enumerate the microorganisms. All organisms, except for Escherichia coli, showed an increase in the measured concentration after blending samples at 22,000 rpm with or without the chemical mixture. Other than fecal streptococci, the organism concentrations decreased with the addition of the Camper's solution in both blended and unblended samples before analyses. There was a statistically significant interaction between the effects of Camper's solution and the effects of blending for all the organisms tested, except for total coliform. Blending did not alter the mean particle size significantly. The results show no correlation between increased total coliform, fecal coliform, and fecal streptococcus concentrations and the mean particle size...Continue Reading.
Effect
of Phosphorus Concentration On The Growth of Cattail Callus Cells
EPA/600/JA-03/290
November 2001
This investigation examined the growth of Typha latifolia (cattail) callus cells grown in five (0, 11, 22, 33, 44 mgL-1) different phosphorus concentrations. The cells were grown for two successive subcultures on semi-solid media, and subsequently in suspension culture with the same phosphorus levels. On semi-solid media, the fresh weight of the cells varied by a maximum of 36% through both subcultures. The 33 mgL-1 phosphorus supplied in the original Gamborgs B5 media promoted the greatest fresh weight of the cells in suspension culture over all other concentrations tested. When grown in suspension culture with 0 and 11 mgvL-1 phosphorus, the cells showed a 42 and 29% reduction in fresh weight, respectively...Continue Reading.
EPA/600/JA-03/290
November 2001
This investigation examined the growth of Typha latifolia (cattail) callus cells grown in five (0, 11, 22, 33, 44 mgL-1) different phosphorus concentrations. The cells were grown for two successive subcultures on semi-solid media, and subsequently in suspension culture with the same phosphorus levels. On semi-solid media, the fresh weight of the cells varied by a maximum of 36% through both subcultures. The 33 mgL-1 phosphorus supplied in the original Gamborgs B5 media promoted the greatest fresh weight of the cells in suspension culture over all other concentrations tested. When grown in suspension culture with 0 and 11 mgvL-1 phosphorus, the cells showed a 42 and 29% reduction in fresh weight, respectively...Continue Reading.
The
Historical Development of Wet-Weather Flow Management
EPA/600/JA-99/275
1999
The management of wet-weather flow (WWF) is necessary to maintain the quality of urban water resources. Throughout history strategies were implemented to control WWF for many reasons, e.g., flood and water quality control, aesthetic improvement, waste removal, and others. A comprehensive literature review has been conducted to determine past strategies and to revisit the historical developments of WWF management. Understanding these past strategies and the development of WWF-management systems over time will aid current and future generations in their WWF-management efforts. This paper summarizes the historical literature review, highlighting the development of WWF management from ancient times to the present. The relationship between past developments, the current state, and the future of WWF management is addressed by identifying several lessons learned...Continue Reading.
EPA/600/JA-99/275
1999
The management of wet-weather flow (WWF) is necessary to maintain the quality of urban water resources. Throughout history strategies were implemented to control WWF for many reasons, e.g., flood and water quality control, aesthetic improvement, waste removal, and others. A comprehensive literature review has been conducted to determine past strategies and to revisit the historical developments of WWF management. Understanding these past strategies and the development of WWF-management systems over time will aid current and future generations in their WWF-management efforts. This paper summarizes the historical literature review, highlighting the development of WWF management from ancient times to the present. The relationship between past developments, the current state, and the future of WWF management is addressed by identifying several lessons learned...Continue Reading.
Differentiating
Human from Animal Isolates of Cryptosporidium parvum
Emerging Infectious Diseases
EPA/600/J-99/376
We analyzed 92 Cryptosporidium parvum isolates from humans and animals by a polymerase chain reaction/restriction fragment length polymorphism method based on the thrombospondin-related anonymous protein 2 gene sequence. Used as a molecular marker, this method can differentiate between the two genotypes of C. parvum and elucidate the transmission of infection to humans...Continue Reading.
Emerging Infectious Diseases
EPA/600/J-99/376
We analyzed 92 Cryptosporidium parvum isolates from humans and animals by a polymerase chain reaction/restriction fragment length polymorphism method based on the thrombospondin-related anonymous protein 2 gene sequence. Used as a molecular marker, this method can differentiate between the two genotypes of C. parvum and elucidate the transmission of infection to humans...Continue Reading.
Evaluation
of Cryptosporidium parvum Genotyping Techniques
Journal of Applied and Environmental Microbiology
EPA/600/J-99/383
We evaluated the specificity and sensitivity of 11 previously described species differentiation and genotyping PCR protocols for detection of Cryptosporidium parasites. Genomic DNA from three species of Cryptosporidium parasites (genotype 1 and genotype 2 of C. parvum, C. muris, and C. serpentis), two Eimeria species (E. neischulzi and E. papillata), and Giardia duodenalis were used to evaluate the specificity of primers. Furthermore, the sensitivity of the genotyping primers was tested by using genomic DNA isolated from known numbers of oocysts obtained from a genotype 2 C. parvum isolate. PCR amplification was repeated at least three times with all of the primer pairs. Of the 11 protocols studied, 10 amplified C. parvum genotypes 1 and 2, and the expected fragment sizes were obtained. Our results indicate that two species-differentiating protocols are not Cryptosporidium specific, as the primers used in these protocols also amplified the DNA of Eimeria species. The sensitivity studies revealed that two nested PCR-restriction fragment length polymorphism (RFLP) protocols based on the small-subunit rRNA and dihydrofolate reductase genes are more sensitive than single-round PCR or PCR-RFLP protocols...Continue Reading.
Journal of Applied and Environmental Microbiology
EPA/600/J-99/383
We evaluated the specificity and sensitivity of 11 previously described species differentiation and genotyping PCR protocols for detection of Cryptosporidium parasites. Genomic DNA from three species of Cryptosporidium parasites (genotype 1 and genotype 2 of C. parvum, C. muris, and C. serpentis), two Eimeria species (E. neischulzi and E. papillata), and Giardia duodenalis were used to evaluate the specificity of primers. Furthermore, the sensitivity of the genotyping primers was tested by using genomic DNA isolated from known numbers of oocysts obtained from a genotype 2 C. parvum isolate. PCR amplification was repeated at least three times with all of the primer pairs. Of the 11 protocols studied, 10 amplified C. parvum genotypes 1 and 2, and the expected fragment sizes were obtained. Our results indicate that two species-differentiating protocols are not Cryptosporidium specific, as the primers used in these protocols also amplified the DNA of Eimeria species. The sensitivity studies revealed that two nested PCR-restriction fragment length polymorphism (RFLP) protocols based on the small-subunit rRNA and dihydrofolate reductase genes are more sensitive than single-round PCR or PCR-RFLP protocols...Continue Reading.