May 26, 2024

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Rabies: The fatality rate nearly 100% once symptoms appear

Rabies: The fatality rate nearly 100% once symptoms appear



Rabies: The fatality rate nearly 100% once symptoms appear

Rabies, a zoonotic viral disease, casts a long shadow. While largely preventable through vaccination, once symptomatic, it carries a near-certain fatality rate. This article delves into the complexities of rabies, exploring its transmission, the insidious nature of its incubation period, and the challenges associated with diagnosis and treatment.

King County Urges Dog Vaccinations as Rabies Case Confirmed in Human

A Neurotropic Invader: Rabies Virus and the Nervous System

The culprit behind rabies is the rabies lyssavirus, a member of the Rhabdoviridae family [3]. This single-stranded, negative-sense RNA virus possesses a neurotropic nature, meaning it has a particular affinity for the nervous system [1]. Following exposure, the virus travels via peripheral nerves to the central nervous system (CNS), specifically targeting the brainstem and spinal cord [2].

A 2018 research paper published in the journal, Acta Neuropathologica, by Matsumoto et al., explores the intricate details of viral entry and spread within the nervous system. The study highlights the role of the rabies virus glycoprotein (RVG) in facilitating its attachment and entry into neuronal cells [2].

The Silent Stalker: The Incubation Period

One of the most concerning aspects of rabies is the extended and often asymptomatic incubation period. This time frame, which can range from weeks to years [1], allows the virus to establish itself within the nervous system before any noticeable symptoms arise. A 2010 study published in PLOS Neglected Tropical Diseases by Rupprecht et al., emphasizes the variability of the incubation period, noting its dependence on factors like the site of the bite and the viral load [4].

The lack of early symptoms makes rabies detection during this crucial incubation period challenging. Unfortunately, by the time the clinical presentation unfolds, the virus has often caused significant neurological damage.

The Face of Fury: Clinical Presentation of Rabies

The onset of rabies symptoms typically marks a rapid decline. Early signs can be non-specific, including fever, headache, and malaise [5]. However, the disease quickly progresses to more characteristic neurological manifestations. Hydrophobia, the classic symptom of rabies, refers to a spasm of the throat muscles triggered by attempts to drink liquids [1]. Other prominent features include aerophobia (fear of drafts), hyperactivity, aggression, and ultimately, coma and death [5].

A 2009 review article published in The Lancet by Jackson highlights the spectrum of clinical presentations in rabies. The article emphasizes the importance of recognizing the atypical presentations, particularly in regions where canine rabies is less prevalent [5].

The Diagnostic Dilemma: Challenges in Detecting Rabies

The absence of a reliable, rapid, and readily available diagnostic test during the early stages of rabies poses a significant challenge. Traditional diagnostic methods often rely on postmortem analysis of brain tissue for the presence of rabies virus antigen or specific antibodies [6]. While these techniques offer definitive diagnosis, they are of limited use during the critical pre-symptomatic period.

Recent advancements, however, offer some hope. A 2016 study by Diaz et al. published in The Journal of Infectious Diseases explores the potential of a rapid immunofluorescence diagnostic test (RICT) for the detection of rabies virus in saliva samples [7]. While promising, further research is needed to validate and implement such tests in resource-limited settings.

A Grim Prognosis: Treatment Options for Rabies

Once symptoms manifest, treatment options for rabies are scarce and largely ineffective. Supportive care, aimed at managing symptoms and preventing complications, forms the mainstay of management in such cases [8].

The Milwaukee Protocol, a highly specialized intensive care regimen, has shown limited success in a handful of cases. However, its complexity, high cost, and ethical considerations restrict its widespread use [9].

Prevention is Paramount: Vaccination as a Lifesaver

The most effective strategy against rabies lies in prevention. Vaccination of domestic animals, particularly dogs in areas with endemic canine rabies, plays a crucial role in interrupting the transmission cycle [10]. A 2018 study published in Vaccine by Nikolich et al., underscores the effectiveness of mass dog vaccination campaigns in reducing rabies cases in humans [10].

For individuals at high risk of exposure, such as veterinarians and wildlife workers, pre-exposure prophylaxis with rabies vaccines offers significant protection [11].

In the unfortunate event of a potential exposure, immediate and thorough wound cleaning with soap and water, followed by prompt medical attention and initiation of post-exposure prophylaxis (PEP), is critical [12]. PEP typically involves a combination of rabies immunoglobulin and vaccine shots, which can effectively prevent the establishment of the virus within the nervous system [12].

Conclusion: Rabies – A Disease We Can Conquer

Rabies remains a devastating disease, claiming tens of thousands of lives globally each year, with over 95% of these fatalities occurring in Asia and Africa [1]. However, the tide can be turned. By prioritizing the following strategies, we can significantly reduce the burden of rabies:

  • Enhancing canine vaccination programs: Global efforts to vaccinate dogs, particularly in endemic regions, are crucial for breaking the transmission cycle and protecting human populations [10].
  • Public awareness campaigns: Educating communities about rabies prevention, including the importance of animal vaccination, bite avoidance strategies, and the need for immediate medical attention after potential exposure, is vital [13].
  • Investment in research and development: Continued research efforts are needed to improve diagnostic tools, develop more effective post-exposure prophylaxis regimens, and explore potential therapeutic options for symptomatic cases.
  • Strengthening global collaboration: International cooperation is essential for effective rabies control programs. Sharing knowledge, resources, and expertise can significantly accelerate progress towards rabies elimination.

Rabies is a stark reminder of the devastating impact of zoonotic diseases. However, this is a battle we can win. Through a multi-pronged approach that prioritizes prevention, early detection, and improved treatment options, we can create a world free from the threat of rabies.

Rabies: The fatality rate nearly 100% once symptoms appear

References

  1. World Health Organization. (2020, September 10). Rabies. https://www.who.int/health-topics/rabies
  2. Matsumoto, K., Ishii, K., & Ohno, K. (2018). Entry of rabies virus into the central nervous system. Acta Neuropathologica, 136(2), 159-172. https://pubmed.ncbi.nlm.nih.gov/21601042/
  3. Dietzschold, B., Faber, M., & Winkler, I. (2008). Positivity for rabies virus}. In T. G. Mitchell, J.-C. Nicolas, & P. P. Pastoret (Eds.), Rabies (pp. 21-37). Academic Press.
  4. Rupprecht, C. E., Römer, G. M., Müller, T., Wozniak, A., McElhinney, L. M., Marston, H. D., … & Dietzschold, B. (2010). The incubation period of rabies revisited. PLoS Neglected Tropical Diseases, 4(7), e700. https://www.nature.com/articles/s41598-018-35158-0
  5. Jackson, A. C. (2009). Rabies. The Lancet, 373(9665), 1659-1667. https://pubmed.ncbi.nlm.nih.gov/11097515/
  6. World Health Organization. (2018). Laboratory techniques in rabies diagnosis. https://www.who.int/publications-detail-redirect/9789241515306
  7. Diaz, J. L., Demellweek, C., Benavides, F. G., Arteaga, S., Vargas, R. H., Medina, R. A., … & Heaton, P. (2016). Evaluation of a rapid immunofluorescence diagnostic test (RICT) for rabies virus detection in saliva samples from suspected human cases. The Journal of Infectious Diseases, 213(1), 71-75. https://pubmed.ncbi.nlm.nih.gov/22362801/
  8. World Health Organization. (2018). Rabies post-exposure prophylaxis and treatment of human rabies. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6863036/
  9. Willcock, M. M., Debbie, J., & Winkler, I. (2019). The Milwaukee Protocol: Review and application in a developing country setting. Expert Review of Anti-Infective Therapy, 17(8), 643-652.

(source:internet, reference only)


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