Description:
Toxoplasmosis is a common food borne zoonosis, occurring annually in approximately 200,000 Dutch citizens, if seroprevalence studies from 1996 are extrapolated (Kortbeek et al. 2004). In 80% of the individuals the infection passes unnoticed whereas 20% of cases are symptomatic whereby symptoms vary from a mild flu like illness to more serious disease such as chorioretinitis (200 cases per year), or congenital toxoplasmosis (70 cases per year) in case primo infection occurs during pregnancy (AFFSSA 2006; van Kemmeren et al. 2006). In The Netherlands cats are the source of infection of the environment due to excretion of Toxoplasma oocysts. Humans become infected via sporulated oocysts in the environment or via consumption of infected food products from animal origin. To date there are no tests to discriminate between these sources of infection and their relative role therefore remains largely unknown although case control studies in neighbouring countries indicate that undercooked meat(products) are the major source. It is clear however that prevention of infection is much easier by addressing the animal source than via the environmental source. For a proper estimate of the role of animal products in human Toxoplasma infection and risk management, more research is needed concerning the various animal sources of infection, the influence of farming systems, the influence of meat product preparation and the behaviour and handling of meat products by consumers.
Research objectives:
The aim of this study is to provide tools to control Toxoplasma infections in humans due to the consumption of food products from organic livestock production systems.
Approach:
The design of the project stems from the veterinary recommendations given in a recent report from the Dutch Food Safety Authority (VWA) on Toxoplasma. After consultation with the RIVM and the VWA and the available funds we have made a selection of research priorities for 2008. For the current situation in The Netherlands we considered further research relating to Toxoplasma infections in pigs the most urgent. With relation to organic pig systems we have formulated the following questions:
1. What is the effect of interventions with relation to farm management on toxoplasma seroprevalence in organic slaughter pigs.
2. What is the effect of treatment procedures of meat from organic pigs on viability of possibly present Toxoplasma parasites.
With relation to the first question we will study the effect of risks we identified earlier such as rodent control or feeding of whey products. The second question will deal with production procedures used by both the large slaughterhouses (Groene Weg/ Vion) as well as the small scale butchers. At this moment it is not clear which procedures are being used to prepare the various hams and sausages when using organic meat and whether these procedures are capable of inactivating Toxoplasma.
Results and products:
The project will provide tools for the government concerning the dilemma between increased animal welfare (organic pig production) and the potential of an increased risk of Toxoplasma infections amongst consumers of these products. Data will be published in a report. We will furthermore present lectures on this topic to stakeholders and the results will also be submitted to international journals. |
