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Evaluation of a Method to Detect Leptospira in Water: Preliminary Results from a Regional Collaboration

Ilima Hawkins (1), Mark Walker (2), Carl Evensen (1)

(1) University of Hawai’i, Department of Natural Resources and Environmental Management, College of Tropical Agriculture and Human Resources
(2) University of Nevada, Department of Natural Resources and Environmental Sciences

Detecting leptospires in environmental waters is technically difficult. Although independent studies have had success with DNA-based tests and selective culturing, the general performance of these procedures have not been evaluated, and no standardized protocol exists. Effective management approaches require environmental testing to identify and monitor contaminated waters. This is of special importance for American Samoa, where the disease is still new and the full impact may not yet be felt.
The objective of this work is to evaluate a proposed water testing protocol for Leptospira.  The method involves sampling large volumes of stream water, purifying leptospires from the sample using a concentrating procedure, and applying a molecular test to detect the presence of spirochetes in the concentrated sample. The first phase of work compares three isolation/concentration procedures including centrifugation, single and nested filtration. The molecular-based test will utilize the Polymerase Chain Reaction test, PCR, to detect the presence of pathogenic leptospires in the purified product. Benchwork is ongoing, and preliminary results show Leptospira are able to pass through a membrane of 0.2um in low frequencies, and they often bind to organic-based filters like NitroCellulose. Click on Detecting Leptospira in Water: Evaluation of a Proposed Method to link to Ms. Hawkins master's defense presentation in PDF format.

Poster presented at the 2007 National Water Quality Conference
(Click on poster for larger view in a PDF format)

leptospirosis poster

Effects of Feral Pigs on Runoff & Water Quality in the MānoaWatershed

Greg Bruland, Chad Browning, and Carl Evensen

University of Hawai’i, Department of Natural Resources and Environmental Management, College of Tropical Agriculture and Human Resources

The overall objective of this project is to determine the role of feral pigs in contributing to sediment, nutrient, and pathogen export from the Manoa Watershed of Oahu.  Specifically, the project will involve three components: (1) establishing fenced pig exclosures in the forested headwaters of the watershed to examine the recovery of understory vegetation and changes in erosion that occur when pigs are excluded from small plots established across various slopes; (2) measuring soil physical and chemical properties in the areas within and adjacent to the exclosure plots in the Manoa Watershed; and (3) measuring sediment, nutrient, and Enterococci (and possibly Leptospirosis) levels in runoff from test plots.

Click on Effects of Feral Pigs on Runoff and Water Quality in the Manoa Watershed: Experimental Design and Preliminary Results to view a PowerPoint presented by Dr. Bruland at a Sustainability Science for Watershed Landscapes conference at the East West Center in November 2007.

Bruland Presentation

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