Page 1 of 8 Proceedings The changing landscape of rabies epidemiology and control Authors: Over the past 20 years, major progress has been made in our understanding of critical 1 Sarah Cleaveland aspects of rabies epidemiology and control. This paper presents results of recent research, Hawthorne Beyer2 highlighting methodological advances that have been applied to burden of disease studies, Katie Hampson1,3 Daniel Haydon1 rabies epidemiological modelling and rabies surveillance. These results contribute new Felix Lankester1,4,5 insights and understanding with regard to the epidemiology of rabies and help to counteract Tiziana Lembo1 misperceptions that currently hamper rabies control efforts in Africa. The conclusion of these 6 Francois-Xavier Meslin analyses is that the elimination of canine rabies in Africa is feasible, even in wildlife-rich areas, Michelle Morters7 Zacharia Mtema1,3 through mass vaccination of domestic dogs and without the need for indiscriminate culling to Maganga Sambo3 reduce dog population density. Furthermore, the research provides valuable practical insights Sunny Townsend1 that support the operational planning and design of dog vaccination campaigns and rabies surveillance measures. Affiliations: 1Boyd Orr Centre for Population and Ecosystem Health, Institute of Introduction Biodiversity, Animal Health Over the past 20 years, much progress has been made in understanding the epidemiology of and Comparative Medicine, College of Medical, rabies in Africa, supporting the view that canine rabies elimination is both feasible and cost- Veterinary and Life Sciences, effective through mass vaccination of domestic dogs (Lembo et al. 2010; Rupprecht et al. 2008; University of Glasgow, World Health Organization [WHO] 2004; WHO 2013). This research has resulted in a groundswell Scotland of momentum amongst rabies scientists and international human and animal health agencies to drive forward ambitious plans for canine rabies elimination. However, despite huge progress in 2ARC Centre of Excellence for Environmental Decisions, some parts of the world, most notably Latin America where canine rabies elimination is targeted Centre for Biodiversity for 2015 (WHO 2012), substantial challenges remain in Africa where few national programmes and Conservation Science, are in existence. University of Queensland, Australia An enduring problem relates to several misperceptions that currently hamper rabies control efforts in Africa (Lembo et al. 2010) (Figure 1). For example, there is a perception that rabies is 3Ifakara Health Institute, Ifakara, Tanzania relatively insignificant as a disease of public health concern; that rabies is a problem of ‘stray’ dogs that are not accessible for parenteral vaccination; that rabies can only be controlled through 4Paul G. Allen School of culling or reduction in the dog population density; and that wildlife play a major role in sustaining Global Animal Health, rabies cycles in Africa. These misperceptions drive a cycle of neglect, where the implementation Washington State University, of ineffective control measures results in demotivation of policy-makers and veterinary field staff United States and fuels the erroneous impression that rabies control is futile. 5Lincoln Park Zoo, Chicago, United States Here we review the most recent evidence from rabies epidemiology studies that address these misperceptions, highlighting how new approaches and analytical techniques are being applied 6World Health Organization, and illustrating how the results are constantly reinforcing the evidence base as to the feasibility of Geneva, Switzerland canine rabies elimination in Africa. 7Department of Veterinary Medicine, University of Rabies burden of disease studies Cambridge, United Kingdom In common with many ‘neglected’ diseases, a principal factor contributing to the low prioritisation Correspondence to: of rabies control has been the lack of information about the burden and impact of rabies, Sarah Cleaveland particularly in low-income countries that are most affected by the disease. The development of a probability-tree model for estimating human rabies deaths from the incidence of suspect Email: rabid animal bite injuries and human post-exposure prophylaxis (PEP) (Cleaveland et al. 2002) sarah.cleaveland@glasgow. has paved the way for several estimates of human rabies incidence in Africa and Asia (Coleman, ac.uk Fèvre & Cleaveland 2004; Fèvre et al. 2005; Hossain et al. 2012; Knobel et al. 2005; Ly et al. 2009; Tenzin et al. 2011). These studies have indicated that rabies incidence in Africa, estimated to be Postal address: Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom Read online: How to cite this article: Cleaveland, S., Beyer, H., Hampson, K., Haydon, D., Lankester, F., Lembo, T. et al., 2014, ‘The changing landscape Onderstepoort Journal of Veterinary Research Scan this QR of rabies epidemiology and control’, 81(2), Art. #731, 8 pages. http://dx.doi.org/10.4102/ ojvr.v81i2.731 code with your smart phone or Note: Proceedings of the 2nd One Health Conference in Africa. Jointly organised by the Southern African Centre for Infectious Disease mobile device Surveillance and the Tanzania National Institute for Medical Research, held at the Snow Crest Hotel in Arusha, Tanzania from 16th to 19th to read online. April 2013: http://www.sacids.org/kms/frontend/index.php?m=119. Copyright: © 2014. The Authors. Licensee: AOSIS OpenJournals. This work is licensed under the Creative Commons Attribution License. http://www.ojvr.org doi:10.4102/ojvr.v81i2.731 Page 2 of 8 Proceedings The consequences of misperceptions The evidence base Misperceptions Reducing the dog Dog ecology, Rabies transmission population density will demographic is not highly density- control rabies studies dependent ‘Stray’ dogs are a Investment of resources in Transmission studies major cause of the Very few African dogs reducing the number or density of (e.g. contact-tracing). rabies problem in are ownerless or ‘strays’ dogs (e.g. culling) epidemiology Africa modelling The rabies problem in Field epidemiology, Domestic dogs are the Failure to invest in mass dog Africa is primarily due genetic analyses, principal reservoir of vaccination to wildlife disease models rabies in Africa Dogs are not easily Dogs are accessible Intervention studies accessible for and mass vaccination vaccination is possible Rabies is difficult Canine rabies control and elimination is feasible Failure to control rabies or impossible to through mass vaccination of dogs control FIGURE 1: Scheme showing how misperceptions about dog ecology and rabies epidemiology have negative consequences for rabies control; and identifying the types of research studies that can generate the evidence-base needed for effective control. ~24 000 deaths per year (Knobel et al. 2005), is at least 100 Empirical data to both parameterise and validate times higher than officially reported. estimates of human rabies deaths have been generated from community surveys (Hossain et al. 2012), large-scale The most recent estimates of rabies burden incorporate more verbal autopsy surveys (Suraweera et al. 2012) and active detailed country-level data, including updated information surveillance and contact tracing (Hampson et al. 2008). on human PEP use. These analyses, part of the global burden Nonetheless, it is clear that these data are still very scarce and of disease studies coordinated by the Partners for Rabies that any figures based on models that incorporate incomplete Prevention, have also included consideration of economic and imprecise data are likely to have a high degree of losses as a result of premature deaths. Overall, using the uncertainty. probability model, global estimates of human rabies deaths Despite these uncertainties, clinical studies in Malawi are similar to previous studies, with an estimated 61 000 have demonstrated that rabies is a more common cause of human rabies deaths per year occurring globally (95% CI, childhood encephalitis than recognised previously and can 52 200–70 700) and 23 800 in Africa (95% CI, 21 000–28 000) be misdiagnosed easily as malaria, even by experienced (WHO 2013). However, the apparent consistency in estimates clinicians (Mallewa et al. 2007). This may seem surprising, masks substantial local variation, most notably the decline in given that rabies exhibits several distinct clinical features in human rabies deaths in several countries in Asia because of humans, such as aerophobia and hydrophobia, but serves to increased availability of rabies PEP and, in some areas, dog highlight the importance of improving awareness amongst rabies control. Whilst any decline in human rabies deaths is clinicians and submitting samples for laboratory diagnosis to to be celebrated, this progress has come at a high cost, with ensure that the rabies disease burden is not masked by high PEP costs in Asia estimated at around US$1.5 billion. These levels of misdiagnosis, particularly in malaria-endemic areas contribute substantially to the estimated global annual cost of Africa. of rabies of US$6bn (95% CI, 4.6–7.3), which also includes productivity losses of US$2bn as a result of premature Although rabies does not have the pandemic potential that deaths (WHO 2013). characterises the emerging zoonoses of greatest concern to http://www.ojvr.org doi:10.4102/ojvr.v81i2.731 Page 3 of 8 Proceedings high-income countries (Figure 2), its burden and impact Level of investment in containment and control in containment of investment Level cannot