Prevalence of immunity presumed using rabies vaccination history and household factors associated with vaccination status among domestic dogs in Japan.

Rabies was eliminated in Japan over 50 years ago; however, the recent increase in the movement of humans and animals across the world highlights the potential threat of disease reentry into the country. The immune status against rabies among the dog population in Japan is not well known; thus, the purpose of this study was to estimate the prevalence of dogs with effective immunity from the vaccination history using a web-based survey. We found that 76.9% (95% confidence interval, 75.8-78.1) of dogs in this study population belonged to the population in which 90% were assumed to have the internationally accepted antibody titer. We showed that dogs taken less frequently for walks were less likely to be vaccinated. Additionally, the frequency of encounters with other dogs during walks and the number of individuals in households were associated with vaccination history. To our knowledge, this study is the first report estimating the prevalence of dogs in Japan with effective immunity against rabies. Further, we identified the population with low vaccination coverage as well as the heterogeneous characteristics of vaccination history among the dog population. These findings contribute to the implementation of an efficient strategy for improving the overall vaccination coverage in Japan and the development of a quantitative risk assessment of rabies.