Toward Elimination of Dog-Mediated Human Rabies: Experiences from Implementing a Large-scale Demonstration Project in Southern Tanzania

Abstract

A Rabies Elimination Demonstration Project was implemented in Tanzania from 2010 through to 2015, bringing together government ministries from the health and veterinary sectors, the World Health Organization, and national and international research institutions. Detailed data on mass dog vaccination campaigns, bite exposures, use of post-exposure prophylaxis (PEP), and human rabies deaths were collected throughout the project duration and project areas. Despite no previous experience in dog vaccination within the project areas, district veterinary officers were able to implement district-wide vaccination campaigns that, for most part, progressively increased the numbers of dogs vaccinated with each phase of the project. Bite exposures declined, particularly in the southernmost districts with the smallest dog populations, and health workers successfully transitioned from primarily intramuscular administration of PEP to intradermal administration, resulting in major cost savings. However, even with improved PEP provision, vaccine shortages still occurred in some districts. In laboratory diagnosis, there were several logistical challenges in sample handling and submission but compared to the situation before the project started, there was a moderate increase in the number of laboratory samples submitted and tested for rabies in the project areas with a decrease in the proportion of rabies-positive samples over time. The project had a major impact on public health policy and practice with the formation of a One Health Coordination Unit at the Prime Minister’s Office and development of the Tanzania National Rabies Control Strategy, which lays a roadmap for elimination of rabies in Tanzania by 2030 by following the Stepwise Approach towards Rabies Elimination (SARE). Overall, the project generated many important lessons relevant to rabies prevention and control in particular and disease surveillance in general. Lessons include the need for (1) a specific unit in the government for managing disease surveillance; (2) application of innovative data collection and management approaches such as the use of mobile phones; (3) close cooperation and effective communication among all key sectors and stakeholders; and (4) flexible and adaptive programs that can incorporate new information to improve their delivery, and overcome challenges of logistics and procurement.

Landscape attributes governing local transmission of an endemic zoonosis: Rabies virus in domestic dogs

“…Once IBD effects were accounted for, we identified the distribution of dogs as the most important predictor of RABV spread, but did not find evidence of dog density effects. This supports assertions that RABV is maintained primarily in domestic dog populations rather than wildlife and that transmission does not depend on dog density (Hampson et al, 2009;Morters et al, 2013). Our results demonstrate the potential for both fundamental and applied insight into the local drivers of endemic RABV spread, but also highlight the need for further methodological development to understand how transmission processes scale from the individual to the landscape.…”

“…Sequenced genomes represent approximately 10% of identified rabies cases during this period; therefore, direct measures of incidence are likely to yield more insight on the impacts of vaccination. Total dog density did not contribute to RABV movement, which substantiates evidence that rabies transmission is not density dependent (Hampson et al, 2009;Morters et al, 2013). Susceptible dog density, however, which accounted for vaccination, was superior to total density as an explanatory variable, but still had limited effect on diffusion.…”

“…Domestic dogs are responsible for over 99% of all human deaths from rabies, which occur predominantly in Asia and Africa (WHO, 2013). Although mass dog vaccination has repeatedly been shown to effectively control rabies in domestic dog populations (Cleaveland, Kaare, Knobel, & Laurenson, 2006;Cleaveland, Kaare, Tiringa, Mlengeya, & Barrat, 2003;Hampson et al, 2007;Morters et al, 2013;Townsend et al, 2013), lingering doubts about the role of wildlife in maintaining infection, and the perceived need to reduce dog populations, affect the implementation of control measures (Lembo et al, 2010). Improved understanding of the local drivers of RABV spread in domestic dog populations could therefore support rabies control efforts, especially as they focus towards the goal of elimination (Hampson et al, 2016;Lankester et al, 2014;Mpolya et al, 2017).…”

“…Culling continues to be used as a response to rabies outbreaks in many parts of the world (Putra, Hampson, & Girardi, 2013;Windiyaningsih, Wilde, Meslin, Suroso, & Widarso, 2004). Although transmission of pathogens such as rabies is often considered to depend on population density (Anderson & May, 1991), empirical evidence suggests that dog density has little effect on RABV transmission (Hampson et al, 2009;Morters et al, 2013).…”

“…Resistance values were assigned to each grid cell to represent the presumed effect of each attribute on rabies virus diffusion, that is, as a facilitator or barrier to spread. A barrier effect is represented by high values denoting greater resistance to movement, whereas facilitators are assigned small resistance values denoting greater ease of movement (calculated as the reciprocal of a presumed conductance value, e.g., a conductance of 100 is represented by a resistance value of 0.01) (Cross et al, 2013;Ferrari, Perkins, Pomeroy, & Bjørnstad, 2011;Morters et al, 2013).…”