Rabies is a critical global health concern, impacting over 150 countries, particularly in Asia and Africa. This viral, zoonotic, and often overlooked neglected tropical disease claims tens of thousands of lives annually, with a staggering 40% of victims being children under 15. The primary mode of transmission to humans is through bites and scratches from infected dogs, which account for 99% of human rabies cases. While the disease is 100% fatal once clinical symptoms manifest, it is entirely preventable with prompt post-exposure prophylaxis (PEP). This includes thorough wound washing, timely administration of rabies vaccines, and, when necessary, rabies immunoglobulins. Recognizing the urgency, global health organizations are committed to eradicating dog-mediated rabies through a comprehensive “One Health” approach, emphasizing mass dog vaccination, accessible PEP, healthcare worker training, improved surveillance, and community awareness about bite prevention.
The Pervasive Threat of Dog-Mediated Rabies
Rabies, a viral disease affecting the central nervous system, is vaccine-preventable and primarily transmitted from animals to humans (zoonotic). Dogs are the principal culprits, responsible for nearly all human rabies transmissions. Tragically, children aged 5 to 14 are disproportionately affected. While rabies can infect any mammal, including domestic animals and wildlife, transmission to humans typically occurs through saliva via bites, scratches, or direct contact with mucous membranes or open wounds. The grim reality is that once symptoms appear, rabies is almost invariably fatal. The global economic burden of rabies is immense, estimated at US$8.6 billion annually, encompassing loss of life, diminished livelihoods, healthcare expenses, and profound psychological trauma. Despite its widespread presence on all continents except Antarctica, an estimated 59,000 people die from rabies each year, a number likely higher due to underreporting. As a neglected tropical disease, rabies disproportionately affects marginalized populations who often lack access to or cannot afford effective human vaccines and immunoglobulins. The cost of PEP, averaging US$108 along with associated travel and lost income, presents a significant financial hurdle for individuals living on as little as US$1–2 per day. Annually, over 29 million people worldwide receive rabies vaccinations.
Beyond Dogs: Other Sources of Rabies Transmission
While dogs are the main vector, other sources pose risks. In the Americas, hematophagous bats have emerged as the primary source of human rabies, with bat-mediated rabies also becoming a growing concern in Australia and parts of Europe. Deaths from exposure to wild mammals like foxes and raccoons are rare, and bites from rodents are not known to transmit rabies. Extremely rare transmission routes include inhaling virus-containing aerosols or consuming raw meat or milk from infected animals, or through organ transplantation. Human-to-human transmission via bites or saliva is theoretically possible but has never been definitively confirmed.
Recognizing the Symptoms of Rabies
The incubation period for rabies typically spans 2–3 months but can range from a week to a year, influenced by factors like the entry point of the virus and the viral load. Initial symptoms are often nonspecific, including fever, pain, and unusual sensations such as tingling, pricking, or burning at the wound site. As the virus progresses to the central nervous system, it causes progressive and ultimately fatal inflammation of the brain and spinal cord. While clinical rabies can be managed, recovery without severe neurological deficits is exceptionally rare.
Rabies presents in two main forms:
- Furious Rabies: Characterized by hyperactivity, extreme excitability, hallucinations, lack of coordination, and hydrophobia (fear of water) and aerophobia (fear of drafts or fresh air). Death usually occurs within days due to cardiorespiratory arrest.
- Paralytic Rabies: Accounts for approximately 20% of human cases. This form progresses more slowly and typically lasts longer than the furious form. Muscles gradually become paralyzed, starting from the wound site, leading to a slow onset of coma and eventual death. This less dramatic presentation can lead to misdiagnosis and under-reporting.
Diagnosing Rabies: Challenges and Protocols
Currently, no WHO-approved diagnostic tools exist to detect rabies infection before the onset of clinical symptoms. Clinical diagnosis can be challenging without a clear history of exposure to a rabid animal or specific signs like hydrophobia or aerophobia. Therefore, accurate risk assessment is paramount in determining the need for PEP. Once symptoms emerge and the disease becomes inevitably fatal, providing comprehensive and compassionate palliative care is recommended. Postmortem confirmation of rabies involves various laboratory techniques to detect the virus, its antigens, or nucleic acids in infected tissues like the brain, skin, or saliva. Testing the biting animal, when feasible, is also crucial.
Prevention Strategies: A Multi-pronged Approach
The Cornerstone: Vaccinating Dogs
The most effective and cost-efficient strategy for preventing human rabies lies in mass dog vaccination programs. Vaccinating dogs, including puppies, at the source of transmission is key. It’s important to note that culling free-roaming dogs has proven ineffective in controlling rabies.
Public Awareness and Education
Public education campaigns targeting both children and adults are vital. These should cover dog behavior, bite prevention strategies, immediate actions to take after a bite or scratch from a potentially rabid animal, and the importance of responsible pet ownership. These awareness efforts complement rabies vaccination programs.
Human Vaccination: Pre-exposure and Post-exposure
Effective human rabies vaccines are available for both prophylactic and emergency use. As of 2024, three WHO pre-qualified human rabies vaccines are globally available: RABIVAX-S, VaxiRab N, and VERORAB.
Pre-exposure Prophylaxis (PrEP): Recommended for individuals in high-risk occupations, such as laboratory workers handling live rabies viruses, and those whose work or activities may lead to direct contact with infected animals, including animal disease control staff and wildlife rangers. PrEP may also be considered for recreational or travel purposes in certain high-risk areas, or for individuals residing in remote, highly endemic regions with limited access to rabies biologicals. It is crucial to remember that PrEP does not eliminate the need for PEP following an exposure.
Post-exposure Prophylaxis (PEP): This is the immediate emergency response to a potential rabies exposure. PEP aims to prevent the virus from reaching the central nervous system. A well-executed PEP protocol, following a thorough wound risk assessment, includes:
- Extensive wound washing with soap and water for at least 15 minutes immediately after exposure.
- A course of rabies vaccine.
- Administration of rabies immunoglobulin or monoclonal antibodies into the wound, if indicated by the severity of the exposure.
Risk Assessment and PEP Indications
The decision to administer a full PEP course depends on the severity of the exposure, categorized as follows:
| Categories of Contact with Suspect Rabid Animal | Post-Exposure Prophylaxis Measures |
|---|---|
| Category I: Touching or feeding animals, licks on intact skin (no exposure) | Washing of exposed skin surfaces; no PEP required. |
| Category II: Nibbling of uncovered skin, minor scratches or abrasions without bleeding (exposure) | Wound washing and immediate vaccination. |
| Category III: Single or multiple transdermal bites or scratches, mucous membrane or broken skin contamination with saliva from animal licks, direct contact with bats (severe exposure) | Wound washing, immediate vaccination, and administration of rabies immunoglobulin/monoclonal antibodies. |
Note: Both Category II and III exposures necessitate human rabies vaccination.
Ensuring Vaccine Quality and Administration
WHO emphasizes that all human rabies vaccines must meet WHO standards. The deployment of substandard vaccines has unfortunately led to public health failures in several countries.
WHO recommends a shift from intramuscular (IM) to intradermal (ID) administration of human rabies vaccines. This method reduces the required vaccine volume and the number of doses, leading to significant cost savings of 60–80% without compromising safety or efficacy. Furthermore, fewer doses can improve patient compliance with the recommended treatment regimen.
WHO’s Global Response to Rabies
Rabies is a priority within WHO’s 2021–2030 Roadmap for the global control of Neglected Tropical Diseases (NTDs). This roadmap sets ambitious targets for the global strategic plan to eliminate human deaths from dog-mediated rabies by 2030, often referred to as “Zero by 30.” Key components of this strategy include:
- Enhancing access to human rabies vaccines: Through collaborative efforts involving WHO and its partners, including Gavi, the Vaccine Alliance, which has integrated human rabies vaccines into its investment strategy.
- Providing technical guidance: Supporting countries in developing and implementing national rabies elimination plans, with a strong focus on strengthening surveillance and reporting systems.
- Building capacity for a “One Health” workforce: Encouraging countries to leverage rabies elimination programs as platforms for multisectoral collaboration.
- Promoting the “United Against Rabies” (UAR) forum: This multi-stakeholder initiative, launched in partnership with the Food and Agriculture Organization (FAO) and the World Organisation for Animal Health (WOAH), serves to advocate for action and investment in rabies control efforts.
