EPINEST, an agent-based model to simulate epidemic dynamics in large-scale poultry production and distribution networks
Fig 7
Multi-strain dynamics and viral mixing in LBMs.
(A-C) Simulations with no inter-farm transmission (βFF = 0). (A) Viral amplification happening through transportation from farm to LBM gates as a function of middlemen-specific transmission weight wMM. This is quantified through the difference between total numbers of exposed and infected chickens sold to vendors and purchased daily by middlemen. (B) Average strain richness (i.e. number of strains) in single LBMs as a function of density ρ of vendor movements (on the x-axis), wMM (from light to dark). Solid and striped bars correspond to low and high hierarchy in vendor movements, respectively. (C) Average Pianka’s index of overlap between pairs of LBMs in terms of their catchment areas. (D-F) Simulations with inter-farm transmission. (D) Average richness per upazila for increasing βFF. Note that the bottom-right map uses a different colour scale. (E,F) Same as (B,C) but for varying βFF and with wMM = 0.001. We set wF = 0.1 in (A-C) and wF = 0.2 in (D-F), while wM = 2.4 and wV = 1 in all panels. Cross-immunity reduces susceptibility to secondary infections to σ = 0.3. Results are averaged over 50 simulations from 10 different synthetic PDNs. In each simulation, statistics are collected for 100 days after an initial transient of 2000 days. The base layer of the maps was obtained from https://gadm.org/download_country_v2.html.