Oral rabies vaccine baiting and targeted removal strategies for dog-mediated rabies outbreak control: a modelling framework for outbreak management

BackgroundSupport for ongoing regional rabies elimination efforts in dogs and reducing cross border transmission is vital to prevent outbreaks in areas that have previously achieved elimination. However, there are limited studies to estimate their potential use as preventive measures. We explore the effectiveness of two control interventions, oral rabies vaccination (ORV) and targeted ring removal (TRR). MethodsA spatio-temporal compartmental microsimulation model of 2200 free-roaming dogs (FRDs) was fitted to surveillance data with one-time, once-per-year and once-per-month rabies importation events modelled. Based on estimated dog biting rates, seven intervention strategies of TRR and ORV were explored to assess transmission risk reduction in 10,000 model runs. ResultsIn the absence of intervention, median human infections over 50 months were 0 (IQR: 0-8), 1 (0-11) and 16 (5-29) for one-time, once-per-year, and once-per-month importation events, with 23.5%, 63.1%, and 99.97% of simulations estimating at least one human case. For one-time and annual importation, 50% dog population TRR reduced this to 6.9% and 29.6%, and 90% ORV coverage down further to 5.0% and 23.5%. Under monthly importation, both TRR and ORV did not substantially reduce the number of simulations without infection but did reduce the number of infections down to 4 (0-12) and 3 (0-8). ConclusionsORV can be successfully utilised for dog-mediated rabies outbreak control in elimination settings but at higher importation rates, may only reduce outbreak size. High TRR rates are required for an equivalent impact which may not be feasible. Additional strong border surveillance and vaccine stockpiling is recommended for outbreak risk mitigation.