Project Number: 1265-32000-076-00
Project Type: Appropriated

Start Date: Dec 16, 2005
End Date: Dec 15, 2010

Objective:
To develop improved serological detection assays for Salmonella and Toxoplasma in humans, pigs, and chickens. Currently available serological tests for Salmonella in swine contain antigens from serovars that do not predominate in U.S. Midwestern swine. As a result, serological tests perform poorly using sera from these animals. We will use serovar specific antigen isolates from Salmonella to develop a serological test which is more sensitive and specific for detection of Salmonella serovars which predominate in Midwestern swine. Until recently, differentiation of foodborne versus oocyst transmission of oxoplasma to humans was impossible. Identification of stage specific antigens from Toxoplasma oocysts have made the development of a validated serological assay possible. We will use these antigens to develop diagnostic methods to determine the most common transmission route of Toxoplasma in humans, and validate a serological test for detection of Toxoplasma infection in chickens.

Approach:
Though previous studies have identified characteristics of high risk management systems, medium and low risk systems have not been completely characterized. We will identify those management systems and strategies that reduce or eliminate Toxoplasma from swine herds on the farm, and develop a comprehensive risk model for the swine industry. Though pork has been identified as a potential source of human infection for Toxoplasma, recent studies suggest that chicken may also be a risk for human transmission. We will analyze Toxoplasma prevalence in chickens raised in different management systems and develop practical interventions for reducing risk of exposure. Until recently, differentiation of foodborne versus oocyst transmission of Toxoplasma to humans was impossible. Identification of stage specific antigens from oocysts have made the development of a validated serological assay possible. We will use these antigens to develop diagnostic methods to determine the most common transmission route of Toxoplasma in humans. The U.S. export market for pork and horsemeat is dependent upon industry compliance with the testing requirements of importing countries. The need for international validation, standardization, and other quality control requirements for digestion-based Trichinella testing is critical as countries compete for export markets. We will collaborate with trading partners and international food safety organizations to harmonize testing procedures for Trichinella in meat products destined for export.