Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 15, 1998
Publication Date: N/A
Interpretive Summary: Infections by the protozoan parasite, Toxoplasma gondii, are widely prevalent in humans and animals. Humans become infected with T. gondii congenitally and by ingesting infected uncooked meat, or by ingesting food and water contaminated with oocysts (resistant form of Toxoplasma) excreted in the feces of infected cats. Scientists at the Beltsville Agricultural Research Center and the University of British Columbia, Canada, describe methods to detect T. gondii oocysts in a municipal water reservoir linked to a large outbreak of acute toxoplasmosis in humans. The methods described will be of interest to biologists, veterinarians, public health workers and parasitologists.
The world's largest outbreak of waterborne toxoplasmosis occurred in a municipality in the western Canadian province of British Columbia. When drinking water emerged as a possible source of infection during the outbreak investigation, a laboratory method was needed to attempt detection of the parasite, Toxoplasma gondii. The method developed was based on the current USEPA method for detection of Cryptosporidium oocysts. Collection of large volumes of drinking water samples and the processing of the cartridge filters were unchanged although identification of Toxoplasma oocysts in filter retentate was carried out using a previously described rodent model. Validation of the method developed was tested using oocysts from a well-characterized strain of Toxoplasma.