Epidemiological characteristics of rabies in Zambia: A retrospective study (2004-2013)

Abstract Background Human and animal rabies have been known to be present in Zambia since the early 1900s. However, systematic reporting, analysis, and dissemination have remained limited. This study aims to quantify trends and patterns in confirmed rabies cases and human dog bites based on reported hospital and laboratory data in Zambia, for the period 2004–2013. We further explore the space–time evolution of risk of confirmed rabies cases and dog bites. Method Data on human dog bites, confirmed rabies cases by province for the period 2004–2013, and on rabid dogs in the period 2005–2012 were analyzed. We calculated the incidence rates, by year and province, and modeled the spatial variability in risk at province level using Poisson spatial regression. Results A total of 14,818 dog bites occurred in all provinces for 2004–2013. The rate of dog bites ranged from 0.01 to 9.18 per 10,000 population. The incidence rate of rabid dogs varied from 2.4 to 17.5 per 10,000 dog population. Over the years, the risk of dog bites varied. The highest risks were at Western province (RR=14.91, 95% CI: 9.08–34.09) in 2004 and Lusaka province from 2009 to 2013. The risk of rabies in dogs increased in Central province (RR=1.79, 95 CI: 1.11–2.74). Conclusion This study reveals increasing trends in reported dog bites and rabies. The increase could be a case of improved reporting due to change in health policies or indeed high incidence necessitated by change in ecosystem. Moreover, the risk of dog bites and confirmed rabies seem to be established in selected provinces. A more detailed epidemiological design is warranted to establish such increases in risk.