Infection with Toxoplasma gondii is acquired through consumption of undercooked infected meat, or by uptake of cat-shed oocysts. Although congenital toxoplasmosis is generally considered to contribute most to the disease burden of T. gondii, ocular disease from acquired infection was recently shown to add substantially to the burden. In addition, toxoplasmosis in immune-compromised individuals usually results from reactivation of an infection acquired earlier in life. Nevertheless, prevention of toxoplasmosis commonly targets mainly pregnant women. We summarize current prevention strategies of congenital toxoplasmosis and evaluate options to improve protection of the general population (including pregnant women). To protect the general population, freezing of meat destined for raw or undercooked consumption is the most readily applicable option, especially when limited to meat from animals originating from nonbiosecure husbandry systems. In the long term, more health benefits are expected from cat vaccination; therefore, development of a cat vaccine and evaluation of its implementation is a research priority.

Shellfish are frequently contaminated by Campylobacter spp, presumably originating from faeces from gulls feeding in the growing or relaying waters. The possible health effects of eating contaminated shellfish were estimated by quantitative risk assessment. A paucity of data was encountered necessitating many assumptions to complete the risk estimate. The level of Campylobacter spp in shellfish meat was calculated on the basis of a five-tube, single dilution MPN and was strongly season-dependent. The contamination level of mussels (<1/g) appeared to be higher than in oysters. The usual steaming process of mussels was found to completely inactivate Campylobacter spp so that risks are restricted to raw/undercooked shellfish. Consumption data were estimated on the basis of the usual size of a portion of raw shellfish and the weight of meat/individual animal. Using these data, season-dependent dose-distributions could be estimated. The dominant species in Dutch shellfish is C. lari but little is known on its infectivity for man. As a worst case assumption, it was assumed that the infectivity was similar to C. jejuni. A published dose-response model for Campylobacter-infection of volunteers is available but with considerable uncertainty in the low dose region. Using Monte Carlo simulation, risk estimates were constructed. The consumption of a single portion of raw shellfish resulted in a risk of infection of 5–20% for mussels (depending on season; 95% CI 0.01–60%). Repeated (e.g. monthly) exposures throughout a year resulted in an infection risk of 60% (95% CI 7–99%). Risks for oysters were slightly lower than for mussels. It can be concluded that, under the assumptions made, the risk of infection with Campylobacter spp by eating of raw shellfish is substantial. Quantitative risk estimates are highly demanding for the availability and quality of experimental data, and many research needs were identified.

Infections with Shiga toxin-producing Escherichia coli O157 (STEC O157) are associated with hemorrhagic colitis, hemolytic uremic syndrome (HUS), and end-stage renal disease (ESRD). In the present study, we extend previous estimates of the burden of disease associated with STEC O157 with estimates of the associated cost of illness in The Netherlands. A second-order stochastic simulation model was used to calculate disease burden as disability-adjusted life years (DALYs) and cost of illness (including direct health care costs and indirect non-health care costs). Future burden and costs are presented undiscounted and discounted at annual percentages of 1.5 and 4%, respectively. Annually, approximately 2.100 persons per year experience symptoms of gastroenteritis, leading to 22 cases of HUS and 3 cases of ESRD. The disease burden at the population level was estimated at 133 DALYs (87 DALYs discounted) per year. Total annual undiscounted and discounted costs of illness due to STEC O157 infection for the Dutch society were estimated at €9.1 million and €4.5 million, respectively. Average lifetime undiscounted and discounted costs per case were both €126 for diarrheal illness, both €25,713 for HUS, and €2.76 million and €1.22 million, respectively, for ESRD. The undiscounted and discounted costs per case of diarrheal disease including sequelae were €4,132 and €2,131, respectively. Compared with other foodborne pathogens, STEC O157 infections result in relatively low burden and low annual costs at the societal level, but the burden and costs per case are high.

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