Timeline: 2007
Client/Partner: Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis.
Study Location: Laboratory Study
Role: Lab Manager
Background:
While reports on waterborne infections with Toxoplasma gondii are emerging worldwide, the detection of this zoonotic parasite in water remains challenging. Lack of standardized and quantitative methods for the detection of T. gondii oocysts in water also limits research on the transport and fate of this pathogen through aquatic habitats. In this project, the ability of hollow-fiber ultrafiltration and capsule filtration was compared to concentrate oocysts in spiked tap water, fresh surface water, and seawater samples. Detection of T. gondii oocysts in concentrated samples was achieved using molecular methods, as well as visually via epifluorescent
microscopy. In addition to oocysts, water samples were spiked with T. gondii surrogate microspheres, and detection of microspheres was performed using flow cytometry and epifluorescent microscopy. Results demonstrate that both water concentration methods followed by microscopy allowed for quantitative detection of T. gondii oocysts and surrogate microspheres. For T. gondii oocysts, microscopy was more sensitive than TaqMan and conventional PCR, and allowed for detection of oocysts in all water samples tested. Compared with flow cytometry, microscopy was also a more cost-efficient and precise method for detection
of fluorescent surrogate microspheres in tap, fresh and seawater samples. This study describes a novel approach for quantitative detection of T. gondii oocysts in drinking and environmental water samples. The techniques described for concentrating and detecting surrogate microspheres have broad application for evaluating the transport and fate of oocysts, as well as the efficiency of water treatment methods for removal of T. gondii from water supplies.
Dr. Alexander Schriewer planned coordinated and executed the hollow-fiber ultrafiltration experiments as well as the sample and data analysis. He also contributed to a resulting peer reviewed publication.
Publication:
Shapiro, K., J. A. K. Mazet, A. Schriewer, S. Wuertz, H. Fritz, W. A. Miller, J. Largier, Conrad P.A. (2010). Detection of Toxoplasma gondii oocysts and surrogate microspheres in water using ultrafiltration and capsule filtration. Water Research (44), 893 – 903.