Science Inventory

LOW PRESSURE ULTRAVEIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS

Citation:

Hayes, S L., E W. Rice, M W. Ware, AND F W. Schaefer III. LOW PRESSURE ULTRAVEIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS. JOURNAL OF APPLIED MICROBIOLOGY 94(1):54-59, (2003).

Impact/Purpose:

1) Refine new, practical methods for the detection of CCL-related and emerging waterborne human protozoa.

2) Perform field tests of devices or methods that have been developed under this task.

3) Evaluate these methods or devices in a variety of water matrices and parasite concentrations.

This work in this task supports CCL2 and 3 and is expected to be completed by 9/07.

Description:

Cysts of Giardia muris were inactivated using a low pressure ultravolet (UV) light source. Cyst viability was detemined by both in vitro excystation and animal infectivity. Cyst doeses were counted using a flow cytometer for the animal infectivity experiments. Using in vitro excystation as the viability indicator, fluences as high as approximately 200 mJ/cm(2) did not prevent some cysts from excysting, thus verifying earlier work. Using animal infectivity, UV fluences of 1.4, 1.9 and 2.3 mJ/cm(2) yielded log(10) reductions ranging from 0.3 to greater than or equal to 4.4. Results indicate in vitro excystation is not a reliable indicator of G. muris cyst viability after UV disinfection.

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Product Published Date: 01/01/2003
Record Last Revised: 12/22/2005
Record ID: 65669

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL EXPOSURE RESEARCH LABORATORY

MICROBIOLOGICAL AND CHEMICAL EXPOSURE ASSESSMENT DIVISION

BIOHAZARD ASSESSMENT RESEARCH BRANCH