Fig. 1.
Hypothetical Trichinella abundance in pigs from controlled housing based on scenario analysis. To find a level of Trichinella larval abundance that matched the upper prevalence limit of 4.17 × 10−10 for pigs from controlled housing, QMRA-T model runs were performed with increasing numbers of larvae per model run, ranging 10–5000 Trichinella larvae per 100 g of diaphragm. Each dot represents one model run. Orange dots represent model runs with increased sample size (5 g instead of 1 g).
1A. Prevalence of positive pools per model run at increasing numbers of Trichinella larvae per 100 g diaphragm (LP100G) on a logarithmic scale are shown. In the range 10–80 LP100G, the average number of positive pools ranged 0.9 × 10−9–3 × 10−9. Black horizontal line represents 1 positive pool.
1B. Corresponding numbers of positive pigs ranged 0.1–0.3 per positive pool, resulting in an overall prevalence ranging 0.9 × 10−10–9 × 10−10 (prevalence of positive pools × prevalence of positive pigs in those pools), which fitted a hypothetical upper prevalence limit of 4.2 × 10−10 for pigs from controlled housing. All other combinations resulted in prevalence values above this upper prevalence limit. Black horizontal line represents 1 positive pig in a positive pool.
1C. Mean number of human trichinellosis cases for the EU corresponding with positive pools and positive pigs in those pools. Black horizontal line represents 1 human trichinellosis case.