Table 1 Parameters and input values used in the baseline scenario.
Description | Parameter | Value | Reference |
|---|---|---|---|
Within-flock transmission rate parameter | β | Pert(0.5,0.8,1.2) | |
Average duration of the infectious period for an infected duck | r | Pert(2,3,4) | |
Within-flock prevalence of HPAIV H5N1 | π | Transmission model | Supplementary Material |
Average number of grazing cycles undergone by an infected nomadic FGD flock during its infectious period | gcycle | Transmission model | Supplementary Material |
Average number of times ducks from a nomadic FGD flock temporarily escape into a neighbouring flock during a grazing cycle | α | Gamma(20,15) | Field data (F) |
Probability that the ducks that are temporarily integrated into the other flock in the field are from the infectious flock | γ | 0.5 | NA |
Average number of ducks that temporarily escape into another flock | n | Pert (1, 5, 20) | NA |
Probability that a FGD flock is susceptible to HPAIV H5N1 (i.e. unvaccinated) | s* | 0.5 | DAH, pers. com. |
Probability that an infected duck that has temporarily joined a susceptible flock infects at least one susceptible duck | δ | [0.1 – 0.6] | NA |
Probability that a susceptible duck that has temporarily joined an infectious flock becomes infected | ε | [0.1 – 0.6] | NA |
Probability that two FGD flocks graze successively on the same rice paddy field during the same production cycle | η | Beta (13, 9) | field data (RPO) |
Probability that the infectious FGD flock is the first to visit the rice paddy field | θ | 0.5 | NA |
Probability that a nomadic FGD flock arrives within 7 days after the departure of the previous flock | κ | Beta (9,3) | field data (RPO) |
Probability that the susceptible flock becomes infected following exposure to environmental contamination with HPAIV H5N1 in the rice paddy field | λ | [0.1 – 0.6] | NA |
Probability that a FGD flock is transported to another grazing site by boat | μboat | Beta (19,4) | field data (F) |
Probability that two flocks are transported together in the same boat | ξboat | 0.31 | field data (T) |
Probability that at least one duck from the susceptible FGD flock becomes infected during transport if it is transported together with an infectious flock in the same boat | οboat | [0.6 – 1.0] | NA |
Probability at least one duck from the susceptible FGD flock becomes infected during transport if the boat is contaminated | τboat | [0.2 – 0.6] | NA |
Time period the transportation vehicle remains infectious | infboat | min(surv, tcdboat) | NA |
Average number of daily journeys for boats | σboat | 1.325 | field data (T) |
Average number of flocks transported per boat journey | φboat | 1.31 | field data (T) |
HPAIV H5N1 environmental survival in a transport vehicle (days) | surv | Pert(2,5,7) | Adapted from19 |
Average length of time until the next cleaning and disinfection of a boat (days) | tcdboat | 0.5*ρboat | NA |
Average duration between two cleaning and disinfection events of vehicle (days) | ρboat* | 30 | field data (T) |
Probability that a FGD flock is transported to another grazing site by truck | μtruck | Beta (10,36) | field data (F) |
Probability that two flocks are transported together in the same truck | ξtruck | 0.31 | field data (T) |
Probability at least one duck from the susceptible FGD flock becomes infected during transport if it is transported together with an infectious flock in the same truck | οtruck | [0.6 – 1.0] | NA |
Probability at least one duck from the susceptible FGD flock becomes infected during transport if the truck is contaminated | τtruck | [0.2 – 0.6] | NA |
Time period the transportation vehicle remains infectious | inftruck | min(surv, tcdtruck) | NA |
Average number of daily journeys for trucks | σtruck | 3 | field data (T) |
Average number of flocks transported per truck journey | φtruck | 1.31 | field data (T) |
Average length of time until the next cleaning and disinfection of a truck (days) | Tcdtruck | 0.5*ρtruck | NA |
Average duration between two cleaning and disinfection events of vehicle (days) | ρtruck* | 10.6 | field data (T) |
