Modeling foot-and-mouth disease dissemination in Brazil and evaluating the effectiveness of control measures

Abstract

Foot-and-mouth disease (FMD) is known to infect multiple food-animal species and to spread among ungulate populations. We introduce a multiscale compartmental stochastic model that incorporates population dynamics, births, deaths, and species-specific transmission dynamics. The model integrates disease dynamics at both the between-farm and the within-farm levels. We developed four scenarios to evaluate the effectiveness of countermeasures, including movement standstill, vaccination, and depopulation. The base scenario involved vaccinating the animals on 20 farms and depopulating four infected farms. The three alternative control scenarios included increasing vaccination and depopulation capacities and no vaccination. Our findings indicate that bovines were the most frequently infected species, followed by swine and small ruminants. After ten days of initial spread, the number of infected farms ranged from 1 to 123, with most simulations (90.12%) predicting fewer than 50 infected farms. Most of the secondary spread occurred within a range of 25 km. Early response to initiating the control action reduces the number of days spent working on control actions while intensifying daily depopulation and vaccination capacity; this may be worth considering in decision-making processes for future control of FMD. Emergency vaccination proved to be efficient in reducing the magnitude and duration of outbreaks, whereas increasing depopulation without the use of vaccination also proved to be effective in eliminating the outbreaks.