Collective Strategies to Control PRRS, a Non-Reportable, Endemic Swine Diseas

Porcine reproductive respiratory syndrome (PRRS), an endemic non-reportable disease, is the most economically damaging of US swine diseases. We use a disaggregated diffusion model to analyze the private and social benefits from actions to control PRSS' outbreaks in a specific control program (RCP-N212) in the US. The model uses distance and network connections between farms to simulate the effects of an outbreak during a 26-week period weighting three hypothetical strains of virus with different levels of virulence (low, medium and high. We first use the model to estimate the losses due to PRRS in the absence of any control investments and then estimate how producers might reduce disease impact by investing in: 1) vaccination of sows against PRSS and/or 2) installation of bio-filters in breeding facilities. We find that adoption of vaccination, the installation of bio-filters, or their joint use results in a significant decrease in disease damage relative to the one occurring in the absence of any control. More importantly, our estimates indicate that private investment has significant external effects, i.e., the use of any control strategy in breeding farms reduces damages on non-breeding farms (and on all non-investing breeding farms). The presence of strong external effects suggests that an industry-coordinated strategy, like an investment subsidy funded by a levy on slaughtered pigs, might further reduce disease losses.