Rabies: An Overview

Introduction

• Rabies is a viral disease causing encephalitis in humans and mammals.
• Historically known as hydrophobia due to the fear of water exhibited by victims.

Symptoms and Progression

• Early symptoms: Fever, abnormal sensations at exposure site.
• Advanced symptoms: Nausea, vomiting, violent movements, excitement, hydrophobia, paralysis, confusion, and loss of consciousness.
• Death is almost certain once symptoms appear.
• Incubation period: 1-3 months, but can vary based on proximity of viral travel along nerves.

Causes and Transmission

• Caused by lyssaviruses such as the rabies virus and Australian bat lyssavirus.
• Transmitted through bites or scratches from infected animals and contact with infected saliva.
• Dogs are the primary transmitters worldwide; bats are a common source in the Americas.
• Diagnosis is possible only after symptom onset.

Prevention and Treatment

• Prevention: Rabies vaccine, animal control, rabies immunoglobulin.
• Treatment: Supportive care; once symptoms present, rabies is incurable.
• Vaccination programs have reduced rabies cases in several regions.
• Immunization is recommended for high-risk individuals.
• Prompt washing of bites can reduce viral particles.

Global Impact

• Approximately 59,000 deaths annually, with high prevalence in Africa and Asia.
• Efforts to control rabies include vaccination and education campaigns.
• Rabies is classified as a neglected tropical disease.
• The global cost of rabies is around $8.6 billion per year.

Pathophysiology

• Rabies virus, part of the Lyssavirus genus, has a single-stranded RNA genome.
• The virus invades the central nervous system, leading to encephalitis.
• Transmission to new hosts is facilitated through altered host behavior.

Diagnosis

• Diagnosis methods include fluorescent antibody test (FAT) and RT PCR.
• Brain tissue examination post-mortem is the most reliable diagnosis method.

Historical Context

• Rabies has ancient origins, with references in the Codex of Eshnunna (~1930 BC).
• Effective vaccines have been developed since the 19th century.

Regional Insights

• Efforts to eradicate rabies vary by region, with some countries achieving rabies-free status.
• Rabies remains endemic in certain Southeast Asian countries due to cost and logistical challenges in vaccination.

Conclusion

• Rabies continues to be a significant global health concern despite advancements in prevention and treatment.
• Ongoing international efforts aim to eliminate rabies-related deaths by 2030.