Table 1.
Description and distribution of input variables for the Paratuberculosis (PTB) survey models.
| Variable | Description | Distribution |
|---|---|---|
| N | Number of herds | Fixed; 24,218 |
| HP | Prevalence of PTB | Fixed; 0.2% |
| IH | Number of infected herds | Binomial (N, HP) |
| NHT | Number of herds tested | Fixed; 6000 |
| IHT | Infected herds tested | Hypergeometric (NHT, IH, N) |
| HS | Herd size | Cumulative (1, 136) |
| WHP | Within-herd prevalence | BetaPERT (0.01, 0.10, 0.50) |
| NIT | Number of infected cows tested | Binomial (HS, WHP); Minimum = 1 |
| SE | Test sensitivity | BetaPERT (0.15, 0.45, 0.87) |
| NID | Number of infected detected | Binomial(NIT, SE) |
| HSE | Herd test sensitivity | NID/NIT |
| SP | Test specificity | Uniform (0.99, 0.999) |
| HSP | Herd test specificity | 1-herd false positive percentage |
| NIHT | Non-infected herds tested | NHT-IHT |
| NICT | Non-infected cows tested | NIHT * 12 |
| FP | Number of false positive herd tests | Binomial (NIHT, 1-HSP) |
| FP:TP | False positive: true positive ratio | ΣNID/FP |