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Extramural Research

Grantee Research Project Results

Grantee Research Project Results

First Confirmation of Waterborne Human Pathogenic Microsporidia

EPA Grant Number: U915304
Title: First Confirmation of Waterborne Human Pathogenic Microsporidia
Investigators: Dowd, Scot E.
Institution: University of Arizona
EPA Project Officer: Smith, Bernice
Project Period: January 1, 1998 through January 1, 2001
Project Amount: $56,524
RFA: STAR Graduate Fellowships (1998)
Research Category: Fellowship - Environmental Microbiology , Biology/Life Sciences , Academic Fellowships



The objective of this research project is to develop research methodologies that can be implemented to study the occurrence and fate of human pathogenic microsporidia in association with environmental water sources.


A combined immunomagnetic spore separation, polymerase chain reaction (PCR)-sequencing, and computer database homology identification approach has been developed to detect and determine the species of environmentally isolated microsporidia. Water concentrates, which were initially indirect fluorescent-antibody assay (IFA) and PCR negative for microsporidia, were spiked with microsporidial spore dilutions, and the detection limit of this method was determined to be less than or equal to six spores. PCR sequencing and computer homology testing also was shown to accurately identify all four of the human pathogenic microsporidia, which were used as controls: Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon hellem, and Encephalitozoon cuniculi. Finally, tertiary wastewater concentrates, which were presumptively IFA positive for microsporidia, were analyzed using these methodologies and confirmed by PCR-sequencing and database homology testing to contain human pathogenic microsporidia.

Supplemental Keywords:

fellowship, human pathogenic microsporidia, polymerase chain reaction, PCR, homology, microsporidial spores, indirect fluorescent-antibody assay, IFA, tertiary wastewater concentrates, Encephalitozoon intestinalis, Encephalitozoon hellem, Encephalitozoon cuniculi, immunomagnetic spore separation, database homology identification approach., RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, INTERNATIONAL COOPERATION, Water, Risk Assessments, Environmental Microbiology, Biochemistry, Physical Processes, Biology, Drinking Water, pathogens, microbiological organisms, waterborne disease, detection, exposure, human exposure, microbial exposure, microbial risk, dietary ingestion exposures, drinking water contaminants, microsporidia, immunofluorescent assay, human health risk, computer homology testing

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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