Global epidemiology of human rabies: systematic review and meta-analysis

Background: Human rabies is a zoonotic disease with substantial global burden. Most cases are reported in Africa and Asia, with indirect estimates of 59,000 deaths per year worldwide. We synthesize data reported through surveillance systems and published literature in order to estimate the burden of human rabies worldwide and to describe epidemiological trends by region.

Methods: Embase and Medline were searched in November 2014, and titles, abstracts, and full-text articles published since 1995 were screened using a prioricriteria. Surveillance data available for cases reported from 1990 through 2013 were analyzed to estimate annual incidence per country. In regions without robust surveillance, summary estimates for annual incidence were based on published literature and calculated by random-effects meta-analysis. Epidemiological trends by region were described in terms of person, place, and time. 

Results: In regions with robust surveillance, China accounts for most cases, reporting 1,172 cases in 2013 (0.86 per 1,000,000 population). Since 1990, both China and Latin America have reported a decline in incidence, attributed to extensive dog vaccination. In Europe, incidence is stable; most indigenous cases are reported in Eastern Europe, particularly Russia, and most cases in other areas are travel-associated. For regions without robust surveillance, 32 articles among 1,737 records reviewed met criteria for meta-analysis. Highest annual incidence was reported in South Asia with 9.2 cases (95% CI, 4.7–18.1) per 1,000,000 population and Sub-Saharan Africa with 1.4 cases (95% CI, 0.5–4.0) per 1,000,000 population—areas in which over 80–90% cases were described as secondary to dog bites. These estimates are likely underestimated; specific reasons for underestimation were characterized by world region.

Conclusion: South Asia and Sub-Saharan Africa continue to be the areas of highest incidence for human rabies. Declines in reported incidence in China and Latin America highlight importance of dog vaccination campaigns for reducing the continuing burden of human rabies. Lack of resources, access, and education as well as inadequate surveillance systems continue to hinder elimination of rabies in many developing countries.