Table 1.
A probabilistic model used to estimate the direct economic losses due to hydatid cysts in livers and lungs of sheep marketed for human consumption at Basrah, south of Iraq.
| Notation | Variable description | Distribution parameterization and model formula | Source of information |
|---|---|---|---|
| Pss_in | Probability of having sheep slaughtered at abattoir (with official meat inspection) | RiskDiscrete ({xi},{pi}) =RiskDiscrete ({10%, 24%, 3%, 25%, 2%, 10%},{10, 5, 30, 10, 5, 25}) |
Expert-opinion (veterinarians (n = 6) interviews) on % of sheep slaughtered in abattoir, out of the total sheep slaughtered for human consumption in Basrah |
| Nss_in | Number of sheep slaughtered per annum at abattoir | Normal (Mean Nss_in, St. Dev Nss_in) =RiskNorm (9011, 2831) |
Retrospective data from abattoir records for numbers of sheep slaughtered from 2008 to 2015 |
| Pss_out | Probability of having sheep slaughtered elsewhere than the abattoir (without official meat inspection) | Probability rule of subtraction; =1 − (Pss_in) |
Model equations |
| Nss_out | Number of sheep slaughtered per annum elsewhere from abattoir | =(Nss_in × Pss_out) / Pss_in | Model equations |
| PH_Lung | Probability of having hydatid cyst in lung of a slaughtered sheep | Beta (α1, α1); where α1 = N of sheep with post-mortem hydatid cyst in lung +1 α2 = N of sheep with post-mortem hydatid cyst in lung − total inspected sheep + 1 =RiskBeta (30, 603) |
Active abattoir survey data (generated in this study) |
| CHFV | Estimate of the full value of a healthy sheep (carcass and offal) marketed in Basrah | Uniform (minimum, maximum) =RiskUniform (143.000, 238.000) |
Expert-opinion (in Iraqi Dinars): Butchers (n = 23) interview |
| CLung | Retail price of a sheep lung sold at local market | Pert (minimum, most likely, maximum) =RiskPert (10.000, 15.000, 17.000) |
Expert-opinion (in Iraqi Dinars): Butchers (n = 23) interview |
| DH_lung | Probable percentage of decline in the retail price of a trimmed lung due to hydatid cyst | Pert (minimum, most likely, maximum) =RiskPert (5.000, 8.000, 10.000) |
Expert-opinion (in Iraqi Dinars): Butchers (n = 23) interview |
| CDH_lung | Estimated retail price of a trimmed (downgraded) whole sheep lung due to hydatid cyst | CLung − DH_lung | Probability distribution of the difference between two distributions |
| PH_Liver | Probability of having hydatid cysts in the liver of a slaughtered sheep | Beta (α1, α1); where α1 = N of sheep with post-mortem hydatid cyst in liver +1 α2 = N of sheep with post-mortem hydatid cyst in liver − total inspected sheep + 1 =RiskBeta (42, 591) |
Active abattoir survey data (generated in this study) |
| CLiver | Retail price of a sheep liver sold at local market | Pert (minimum, most likely, maximum) =RiskPert (10.000, 15.000, 17.000) |
Expert-opinion (in Iraqi Dinars): Butchers (n = 23) interview |
| DH_liver | Probable percentage of decline in the retail price of a trimmed liver due to hydatid cysts | Pert (minimum, most likely, maximum) =RiskPert (5.000, 8.000, 10.000) |
Expert-opinion (in Iraqi Dinars): Butchers (n = 23) interview |
| CDH_liver | Estimated retail price of a trimmed (downgraded) whole sheep liver due to hydatid cysts | CLiver − DH_liver | Probability distribution of the difference between two distributions |
| TotalLLL | Total estimated annual cost due to hydatid cysts in the lungs and liver of a slaughtered sheep | =(Nss_in × PH_Lung × CDH_lung) + (Nss_out × PH_Lung × CDH_lung) + (Nss_in × PH_Liver × CDH_liver) + (Nss_out × PH_Liver × CDH_liver) | Product of model distributions: output estimated after 50,000 iterations using a Monte Carlo simulation |
| TotalPV | Estimated annual meat products value of sheep marketed in Basrah province | =(Nss_in + Nss_out) × CHFV | |
| PercPVL | Proportion of annual losses in meat products value of sheep marketed in Basrah province | =(TotalLLL / TotalPV) × 100 |