By Sarah Cleaveland, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, U.K. G12 8QQ
Rabies is one of the world’s deadliest and most frightening diseases and although well controlled in many of the wealthier countries of the world, remains rampant throughout much of Africa and Asia. From the earliest historical records, people have been writing about the disease and the link between human rabies and the bite of rabid dogs has long been recognised. Today, dogs still remain the most important reservoir of the rabies virus, and responsible for around 60,000 human rabies deaths every year, mostly in Asia and Africa.
Research into the prevention of rabies also has a long history, with Louis Pasteur successfully developing an effective vaccine and vaccination strategy to prevent rabies more than 100 years ago. Several excellent vaccines are now available to prevent rabies in people following bites and exposures from rabid animals (post-exposure prophylaxis, PEP) as well as preventing disease in many animal reservoirs, including domestic dogs. The disease is essentially 100% preventable. So, why do so many people still die from rabies every year?
The answer is simple but stark. People are dying because of inequalities in access and affordability of human vaccines and because of inequalities in access and affordability of animal health services. The vast majority of people who die from rabies live in poor, remote and often marginalised communities, where dog rabies remains uncontrolled and where prompt access to PEP is limited. Any delay beyond 24 hours in receiving PEP carries a risk that rabies will develop. In many rural areas of Africa and Asia, vaccine shortages are common, and people bitten face many challenges in reaching clinics for timely administration of PEP. Cases of human rabies, although horrifying and traumatising to those involved in caring for patients, often pass undocumented and unnoticed by those in authority.
The inequality of access to life-saving vaccination, both for human post-exposure prophylaxis (PEP) and dog vaccination, is one of the reasons why it is so important to have a target of elimination. If we can eliminate infection at source, primarily the domestic dog reservoir, people will be protected against rabies regardless of socio-economic status. Setting a target for elimination is also critical for mobilising resources, building political commitment and catalysing coordinated action across regions and across disciplinary sectors. If we do nothing to change the status quo, not only will more than 1 million people die from rabies by 2035, but the demand for costly human vaccine will continue to escalate.
Lack of action on rabies in Asia and Africa has not only been hampered by lack of political will and resources, but by widespread misperceptions about the feasibility of controlling rabies in dogs. For example, because most dogs in Asia and Africa are free-roaming, people often still think that it would be impossible to vaccinate enough dogs to control the disease. However, where dog vaccination campaigns have been well organised and coordinated, it has been shown that, across many different settings and cultures, sufficient dogs can be vaccinated. There is nothing fundamentally intractable about eliminating canine rabies. Of course, it requires hard work, commitment, organisation and resources. But it has already been achieved in many parts of the world and it can also be achieved in Africa and Asia.
The current target for elimination is set at zero human deaths from dog-mediated rabies by 2030. This is an ambitious but entirely feasible target but requires action to bolster both arms of human rabies prevention – improved access to PEP and scaling up of mass dog vaccination to control infection at source. A major step forward has been the inclusion of human rabies vaccine in the Gavi investment strategy of 2019. However, this investment will be conditional upon parallel commitments to scaling up mass dog vaccination. And here our greatest challenges still remain. There are still many countries where dog vaccination is being carried out only at a very limited scale or only sporadically. Larger-scale implementation and coordination is essential. But with the current emphasis on privatisation of veterinary service delivery, and with only very meagre budgets available to most government veterinary services, we need mobilise resources and technical capability to support scaling up and regional coordination of mass dog vaccination.
We do have some excellent examples that provide grounds for much optimism. Several countries in Latin America, such as Chile, Paraguay and Uruguay and many central America countries, have already eliminated canine rabies through coordinated mass dog vaccination campaigns. In 2019, Mexico was the first country to be validated as free of human rabies transmitted by dogs within new WHO frameworks established for certifying freedom from disease. Key to these successes has been the political commitment and investment in mass dog vaccination, along with effective trans-boundary coordination of rabies control efforts. In Asia, countries such as Bangladesh and the Philippines have been making substantial progress, with recognition of the critical need and feasibility of mass dog vaccination a key element in progress.
More than 100 years ago, Louis Pasteur reflected that elimination of rabies would be a blessing for humanity. This holds true today, but the benefits also extend beyond rabies. Tackling inequalities to reduce the threat of rabies in underserved communities can help strengthen human and animal health systems and can build trust in these systems. These benefits have relevance for the control of many other neglected and emerging health threats.
We all have a part to play in achieving this goal of rabies elimination. Richer countries that are currently free of dog rabies not only have resources and technical expertise that can be deployed to support countries in Asia and Africa in their elimination efforts, but also have a powerful voice in shaping global health policy. Through the webinar presentation, I hope people will have a better appreciation of the terrible realities that face millions of people affected by rabies each year. I hope people will understand the feasibility, practicalities and some of the remaining challenges of rabies elimination. Most importantly, I hope that people will care enough about rabies elimination to make this a reality.
Further information can be obtained from:
Lankester F, Hampson K, Lembo T, Palmer G, Taylor L and Cleaveland S. (2014) Implementing Pasteur’s vision for rabies elimination. Science 345: 1562-1564. doi: 10.1126/science/1256306.
Hampson K et al (2015) Estimating the Global Burden of Endemic Canine Rabies. PLoS Negl Trop Dis 9(4): e0003709. doi:10.1371/journal.pntd.0003709
WHO Rabies Modelling Consortium (2019) The potential impact of provision of rabies postexposure prophylaxis in Gavi-eligible countries: a modelling study.
Lancet Infect Dis. 19: P102-111. http://dx.doi.org/10.1016/S1473-3099(18)30512-7