Reviewing Solutions of Scale for Canine Rabies Elimination in India

Challenges of rabies surveillance in Madagascar based on a mixed method survey amongst veterinary health officers

Introduction

In Madagascar, rabies is endemic and a notifiable disease. The objective of this mixed study was to understand the challenges faced by the Veterinary Health Officers (VHOs) in the current rabies surveillance system in Madagascar.

Methods

A survey was conducted from mid-April to the end of July 2021 during which all officially-listed VHOs (N = 150) were contacted by phone at least twice. Participants, representative of the 22 regions of Madagascar, were interviewed by phone based on a semi-structured questionnaire on (1) their knowledge of rabies epidemiology in their area of activities, (2) the occurrence of human and animal rabies and the species affected in the region where they work, (3) the factors that might influence rabies surveillance depending on (a) their activities and area of operation, (b) the socio-cultural aspects of local communities, and (c) the general organization of animal rabies surveillance.

Results

The majority (80/90) of VHOs declared having been informed of at least one suspected or confirmed case of human and/or animal rabies in their area of activity during their work as VHOs: at least once a month for 11 of them, at least once a year for 40 and with undetermined frequency for 29. Several obstacles hinder the surveillance of rabies resulting in under-reporting. The lack of funds to access suspect animals, collect, pack and ship samples in compliance with biosecurity measures and the cold chain, was mentioned as a major obstacle to surveillance. The second barrier is socio-cultural: in many large coastal regions, dogs are taboo and VHOs fear rejection by the community if they treat dogs.

Discussion and conclusion

While the general population requires information on the rabies situation in Madagascar and on how to proceed in the event of a bite, veterinarians and decision-makers need to be fully aware of an evidence-based approach to rabies surveillance, prevention and control. Communication between the human and animal health sectors should be improved. Politicians need to be persuaded of the importance of funding to eliminate rabies in Madagascar. The adoption, in early 2023, of a national strategic plan for rabies control is a first step in this direction.

Prospects for dog rabies elimination in Nigeria by 2030

The attainment of the global target of zero dog-mediated human rabies by 2030 depends on functional rabies programmes. Nigeria, a rabies-endemic country, and the most populous country in Africa has a very poor rabies control strategy with a score of 1.5 out of 5 based on the Stepwise Approach towards Rabies Elimination (SARE). In this article, we report a scoping review that we conducted to highlight the strengths, weaknesses, opportunities and threats as well as situational analysis of rabies control in Nigeria and suggest a timeline for key activities that are needed to ensure zero by 30. Our findings reveal that rabies is grossly under-reported as only 998 human and 273 dog-suspected rabies cases were reported across Nigeria between 2017 and 2022. Our literature review also demonstrates a paucity of information on rabies in both human and animal health sectors. A total of 49 studies on dog rabies in Nigeria, with a predominance of reports from the North Central geopolitical region (48%, n = 23) were therefore included in this study. Currently, only 16.2% (n = 6/37) of Nigerian states have available data related to the estimated dog populations, the dog ownership rates, the vaccination status of dogs or the incidence of dog bites. Based on a dog-to-human ratio of 1:16.3, we estimated that the dog population in Nigeria was 12,969,368 (95% CI: 12,320,900-13,617,836). Thus, to attain herd immunity and dog rabies control in Nigeria, at least 9.1 million dogs must be vaccinated annually. Our review reveals that, despite the strengths and available opportunities to achieve rabies control in Nigeria by 2030, the weaknesses and challenges will make the attainment of zero by 30 very difficult or impossible. Nigeria's best-case scenario by the year 2030 is SARE stage 3-4 (control-elimination) out of 5. Otherwise, the rabies control programme might not surpass SARE stages 2-3. To attain zero by 30, Nigeria must re-strategize its current rabies control programme by funding and implementing the national strategic plan for rabies control, creating a rabies desk office in the 37 states (FCT inclusive), rigorously conducting mass vaccination campaigns, providing post-exposure prophylaxis, prioritizing mass enlightenment with a focus on responsible pet ownership and conduct baseline national rabies surveillance in the animal and human health sectors.

Optimising rabies vaccination of dogs in India

Dog vaccination is the key to controlling rabies in human populations. However, in countries like India, with large free-roaming dog populations, vaccination strategies that rely only on parenteral vaccines are unlikely to be either feasible or successful. Oral rabies vaccines could be used to reach these dogs. We use cost estimates for an Indian city and linear optimisation to find the most cost-effective vaccination strategies. We show that an oral bait handout method for dogs that are never confined can reduce the per dog costs of vaccination and increase vaccine coverage. This finding holds even when baits cost up to 10x the price of parenteral vaccines, if there is a large dog population or proportion of dogs that are never confined. We suggest that oral rabies vaccine baits will be part of the most cost-effective strategies to eliminate human deaths from dog-mediated rabies by 2030.

Evaluation of country infrastructure as an indirect measure of dog-mediated human rabies deaths

Background

Rabies is a neglected disease, primarily due to poor detection stemming from limited surveillance and diagnostic capabilities in most countries. As a result, there is limited ability to monitor and evaluate country, regional, and global progress towards the WHO goal of eliminating human rabies deaths by 2030. There is a need for a low-cost, readily reproducible method of estimating rabies burden and elimination capacity in endemic countries.

Methods

Publicly available economic, environmental, political, social, public health, and One Health indicators were evaluated to identify variables with strong correlation to country-level rabies burden estimates. A novel index was developed to estimate infrastructural rabies elimination capacity and annual case-burden for dog-mediated rabies virus variant (DMRVV) endemic countries.

Findings

Five country-level indicators with superior explanatory value represent the novel "STOP-R index:" (1) literacy rate, (2) infant mortality rate, (3) electricity access, (4) political stability, and (5) presence/severity of natural hazards. Based on the STOP-R index, 40,111 (95% CI 25,854-74,344) global human rabies deaths are estimated to occur in 2022 among DMRVV-endemic countries and are projected to decrease to 32,349 (95% CI 21,110-57,019) in 2030.

Interpretation

The STOP-R index offers a unique means of addressing the data gap and monitoring progress towards eliminating dog-mediated human rabies deaths. Results presented here suggest that factors external to rabies programs influence the successes of rabies elimination, and it is now possible to identify countries exceeding or lagging in expected rabies control and elimination progress based on country infrastructure.

Eliminating dog-mediated rabies: challenges and strategies

Rabies is an acute encephalitis caused by a lyssavirus. It is primarily transmitted through bites of infected dogs which results in the worldwide death of an estimated 59000 humans every year. The disease is preventable through the application of post-exposure prophylaxis (PEP) and its elimination has been demonstrated in many countries by applying multiple interventions simultaneously. Nonetheless, rabies is still widespread in many developing countries, primarily due to the poor implementation of intervention strategies that include inadequate dog-bite wound management practices, unavailability/unaffordability of PEP by the communities, failure to control the disease in free-roaming dogs and wildlife, improper dog population management, weak surveillance and diagnostic facilities and a lack of a One Health approach to the disease. In this review, strategies to control dog-mediated rabies through a One Health approach were discussed. We recommend applying multiple interventions against the disease by involving all the concerned stakeholders in selected urban and rural areas of the countries where rabies is endemic. An empirical demonstration of disease freedom in the selected areas through a One Health approach is needed to convince policymakers to invest in rabies prevention and control on the national level. This multifaceted One Health control model will enhance the likelihood of achieving the goal of global rabies eradication by 2030.

Rabies control in South Asia requires a One Health approach

Rabies is a vaccine-preventable viral disease present in more than 150 countries around the world. Globally, almost 60,000 people die each year from rabies, of which more than 58% are in Asia and around 45% in South Asia with especially high incidence in India, Pakistan and Bangladesh. Vaccination coverage of both people and stray dogs is low in the region and in general people are not given enough protection and information about pre- and post-exposure prophylaxis. Engagement of multiple sectors and One Health collaboration including community education, awareness programmes and vaccination campaigns are critical to control and elimination of rabies.

Role of Oral Rabies Vaccines in the Elimination of Dog-Mediated Human Rabies Deaths

Domestic dogs are responsible for nearly all the »59,000 global human rabies deaths that occur annually. Numerous control measures have been successful at eliminating dog-mediated human rabies deaths in upper-income countries, including dog population management, parenteral dog vaccination programs, access to human rabies vaccines, and education programs for bite prevention and wound treatment. Implementing these techniques in resource-poor settings can be challenging; perhaps the greatest challenge is maintaining adequate herd immunity in free-roaming dog populations. Oral rabies vaccines have been a cornerstone in rabies virus elimination from wildlife populations; however, oral vaccines have never been effectively used to control dog-mediated rabies. Here, we convey the perspectives of the World Organisation for Animal Health Rabies Reference Laboratory Directors, the World Organisation for Animal Health expert committee on dog rabies control, and World Health Organization regarding the role of oral vaccines for dogs. We also issue recommendations for overcoming hesitations to expedited field use of appropriate oral vaccines.

Modelling the challenges of managing free-ranging dog populations

Free-ranging domestic dogs (FRD) are not only vectors of zoonoses of public health concern, but also pose direct threats to humans, livestock, and endangered wildlife. Many developing countries have struggled to control FRD, despite using both lethal and non-lethal methods. India has amongst the highest FRD populations globally and the highest incidences of dog-mediated human rabies, but only deploys Catch-Neuter-Vaccinate-Release (CNVR) for FRD control as a humane alternative to lethal methods, without evidence of it working successfully. Here, we use an agent-based dog population dynamics model to examine the time, effort, financial resources, and conditions needed to successfully control FRD in a typical urban setting. We simulate several scenarios, from an "ideal world" closed population with easily accessible dogs, to a more realistic open population with heterogeneity in catchability of dogs. In only one "best-case" scenario, CNVR resulted in a significant and lasting reduction in FRD, but with vaccination rates peaking only at 35%, which is half the WHO-recommended coverage. The customisable and portable modelling tool that we have developed allows managers to simulate real world processes and understand the expected effort needed to reduce regional dog populations, and assess methods for achieving effective anti-rabies vaccination coverage.

Humoral Immune Response of Thai Dogs after Oral Vaccination against Rabies with the SPBN GASGAS Vaccine Strain

Applied research is crucial in pushing the boundaries and finding a solution to the age-old problem of dog-mediated rabies. Although oral vaccination of dogs is considered to have great potential in mass dog vaccination campaigns and could have far-reaching benefits, it is perhaps the most ignored of all available tools in efforts to eliminate dog-mediated rabies, not least because of limited data on immunogenicity, efficacy, and safety of potential oral rabies vaccine candidates. In this study, the long-term immunogenicity in local Thai dogs after oral administration of the highly attenuated 3rd generation rabies virus vaccine strain SPBN GASGAS was assessed. The oral rabies vaccine was administered to dogs by either direct oral administration (n = 10) or by offering a vaccine loaded intestine bait (n = 15). The humoral immune response was then compared to three groups of dogs; a group that received a parenteral delivered inactivated rabies vaccine (n = 10), a group offered a placebo intestine bait (n = 7), and a control group (n = 4) for an observation period of 365 days. There was no significant difference in the immune response of dogs that received oral and parenteral vaccine in terms of magnitude, kinetics, and persistence of both rabies virus (RABV) neutralizing (RFFIT) and binding (ELISA) antibodies. Although the single parenteral injection of an inactivated rabies vaccine mounted a slightly higher humoral immune response than the orally delivered live vaccine, RABV specific antibodies of both types were still detectable after one year in most animals for all treatment groups and resulted in no difference in seropositivity. Characterization of rabies specific antibodies revealed two main classes of antibodies involved in the immune response of dogs vaccinated. While IgM antibodies were the first to appear, the succeeding IgG response was mainly IgG2 dominated independent of the vaccine type used. The results support the view that SPBN GASGAS induces a sustained detectable immune response in local dogs both after direct oral administration and via bait application.