Rabies-induced behavioural changes are key to rabies persistence in dog populations: investigation using a network-based model

Abstract

18Canine-rabies was endemic pre-urbanisation, yet little is known about how it persists in small 19 populations of dogs typically seen in rural and remote regions. Our objectives were to simulate 20 rabies outbreaks in such populations (50-90 dogs) using a network-based model, and 21 investigate the influence of rabies-induced behavioural changes. 22Such changes -increased bite frequency and either roaming or paralysis that increased the 23 number or duration of contacts, respectively -were essential for disease propagation. Spread 24 occurred in approximately 50% of model simulations and in these, very low case rates (2.0-2.6 25 cases/month) over long durations (95% range 20-473 days) were predicted. Consequently, 26 disease detection is a challenge, risking human infection and spread to other communities via 27 dog movements. Even with 70% pre-emptive vaccination, spread occurred in >30% of model 28 simulations (in these, median case rate was 1.5/month with 95% range of 15-275 days 29 duration). 30We conclude that the social disruption caused by rabies-induced behavioural change is the key to 31 explaining how rabies persists in small populations of dogs. We predict that vaccination of 32 substantially greater than the recommended 70% of dog populations is required to prevent rabies 33 emergence in currently free rural areas. 34 35