Abstract:
Dog rabies has been recognized from ancient times and remains widespread across the
developing world with an estimated 59,000 people dying annually from the disease. In 2011
a tri-partite alliance consisting of the OIE, the WHO and the FAO committed to globally eliminating dog-mediated human rabies by 2030. Regardless of global support, the responsibility
remains with local program managers to implement successful elimination programs. It is
well known that vaccination programs have a high probability of successful elimination if
they achieve a population-coverage of 70%. It is often quoted that reducing population turnover (typically through sterilizations) raises the probability for local elimination by maintaining herd immunity for longer. Besides this, other factors that affect rabies elimination are
rarely mentioned. This paper investigates the probability for local elimination as it relates to
immunity, fecundity, dog population size, infectivity (bite rates), in-migration of immunenaïve dogs, and the initial incidence. To achieve this, an individual-based, stochastic, transmission model was manipulated to create a dataset covering combinations of factors that
may affect elimination. The results thereof were analysed using a logistic regression model
with elimination as the dependent variable. Our results suggest that smaller dog populations, lower infectivity and lower incidence (such as when epidemics start with single introductions) strongly increased the probability for elimination at wide ranges of vaccination
levels. Lower fecundity and lower in-migration had weak effects. We discuss the importance
of these findings in terms of their impact and their practical application in the design of dogmediated rabies control programs.
