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Infectious Diseases

Rabies (Clinical Disease)

A fatal viral encephalitis caused by the rabies virus (a Lyssavirus), transmitted to humans typically through the saliva of infected animals (usually via bites, scratches, or licks on broken skin/mucous membranes). Once clinical symptoms develop, the disease is almost invariably fatal.

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Referral and warning signs

When to refer

Refer ALL individuals with potential rabies exposure IMMEDIATELY for assessment and initiation of Post-Exposure Prophylaxis (PEP). Refer confirmed/suspected clinical rabies cases to hospital (H/RR) for palliative care and infection control.

Red flags

  • Hydrophobia.
  • Aerophobia.
  • Unexplained progressive encephalitis or ascending paralysis following animal bite/exposure.
  • Paraesthesia or pain at site of previous bite.

Signs and symptoms

  • Incubation period: Highly variable, typically 1-3 months, but can range from <1 week to >1 year.
  • Prodromal Phase (2-10 days):
  • - Non-specific symptoms: Fever, malaise, headache, fatigue, anorexia, nausea, vomiting.
  • - Pain, tingling, itching, or paraesthesia at the site of the bite/exposure (highly suggestive if present).
  • Acute Neurologic Phase (2-7 days): Two main forms:
  • - Furious Rabies (~80%):
  • - Episodic psychomotor agitation, hyperactivity, restlessness, anxiety, confusion, hallucinations.
  • - Hydrophobia: Painful, violent spasms of pharyngeal/laryngeal/inspiratory muscles triggered by attempting to drink or sight/sound of water.
  • - Aerophobia: Similar spasms triggered by draft of air.
  • - Fluctuating consciousness.
  • - Autonomic instability (hypersalivation, sweating, priapism, unstable BP/HR).
  • - Paralytic ('Dumb') Rabies (~20%):
  • - Progressive ascending flaccid paralysis, often starting near bite site.
  • - Mimics Guillain-Barré Syndrome.
  • - Fever and headache common.
  • - Consciousness often preserved longer than in furious form.
  • - Hydrophobia/aerophobia usually absent.
  • Coma Phase: Both forms progress to coma, autonomic failure, respiratory arrest, and death, usually within 7-10 days of symptom onset.

Risk factors

  • Bite, scratch, or lick from a potentially rabid animal (dogs are main reservoir in many developing countries; also cats, bats, monkeys, wild carnivores).
  • Exposure of broken skin or mucous membranes to saliva or nervous tissue of infected animal.
  • Failure to receive or complete timely Post-Exposure Prophylaxis (PEP) after a potential exposure.
  • Living in or travelling to rabies-endemic areas.
  • Occupational risk (veterinarians, animal handlers, lab workers).

Diagnosis

Clinical assessment

Diagnosis based on characteristic clinical syndrome (encephalitis with hydrophobia/aerophobia OR ascending paralysis) following a history of potential animal exposure. Often diagnosis is made clinically when typical symptoms appear.

Differential diagnosis

  • Tetanus (trismus, spasms, but usually clear sensorium, no hydrophobia).
  • Other viral encephalitis (Herpes Simplex, Arboviruses).
  • Guillain-Barré Syndrome (ascending paralysis, but usually symmetrical, sensory changes, CSF high protein).
  • Psychiatric disorders / Hysteria.
  • Poisoning (e.g., strychnine).

Investigations

  • Ante-mortem diagnosis difficult, often clinical. Tests usually confirm posthumously.
  • - Saliva: RT-PCR for rabies virus RNA.
  • - Skin Biopsy: (Nape of neck at hairline) - DFA staining or RT-PCR for viral antigen/RNA.
  • - CSF: RT-PCR or antibody detection (usually positive later in illness). CSF often normal initially.
  • - Serum: Antibody detection (appears late, after symptoms start, may be absent if patient dies quickly).
  • Post-mortem: Brain tissue examination (DFA, histology for Negri bodies, RT-PCR, culture) is definitive.

Diagnostic criteria

Clinical syndrome + History of exposure. Laboratory confirmation difficult ante-mortem.

Management

Non-pharmacological management

  • Once symptoms develop, rabies is essentially untreatable and fatal. Focus is on Palliative Care.
  • Hospital Admission: Isolate patient in quiet room to minimize stimuli triggering spasms.
  • Strict Infection Control Precautions: Standard + Contact + Droplet precautions. Use PPE (gloves, gown, mask, eye protection) when handling patient or potentially contaminated fluids/secretions. Saliva is infectious.
  • Comfort measures.
  • Maintain hydration/nutrition as possible.
  • Avoid futile intensive interventions once diagnosis established.

Pharmacological treatment

  • Palliative Care:
  • - Sedation (e.g., Diazepam, Midazolam, Morphine) to manage agitation, spasms, pain, anxiety.
  • - Antipsychotics (e.g., Haloperidol) for agitation/hallucinations.
  • - Medications to reduce saliva production (e.g., Glycopyrrolate) may provide comfort.
  • - There is NO curative antiviral treatment.

Monitoring

Focus on patient comfort, symptom control (pain, agitation, spasms), and family support. Monitor airway minimally to avoid triggering spasms.

Complications

  • Progression to coma.
  • Respiratory failure.
  • Autonomic collapse.
  • Cardiac arrest.
  • Death (almost universal).

Prevention

  • Post-Exposure Prophylaxis (PEP): CRITICAL intervention AFTER exposure but BEFORE symptom onset.
  • - Immediate and thorough wound washing with soap and water for at least 15 minutes.
  • - Rabies Vaccine: Administration of effective rabies vaccine according to recommended schedule (e.g., Essen regimen - days 0, 3, 7, 14, 28; or Zagreb regimen).
  • - Rabies Immunoglobulin (RIG): Administration of Human RIG (HRIG) or Equine RIG (ERIG) infiltrated into and around the wound(s) on day 0 for severe exposures (Category III, some Category II), along with first vaccine dose. Provides passive immunity.
  • *(See UCG Section 1.2.1.3 for details on wound categories and PEP).*
  • Pre-Exposure Prophylaxis (PrEP): Recommended for high-risk individuals (vets, animal handlers, lab workers, travellers to high-risk areas).
  • Animal Control: Mass vaccination of domestic dogs, control of stray animal populations, wildlife rabies control (where applicable).

Patient education

  • For Exposure: Extreme importance of immediate wound washing and seeking prompt medical care for PEP. Need to complete full vaccine schedule. Information about RIG if given.
  • For Clinical Disease: Explanation of fatal nature once symptoms start. Focus on palliative care, comfort, dignity. Need for strict infection control by caregivers/staff. Counseling for family.
  • General: Avoid contact with unknown/stray animals, especially if behaving abnormally. Importance of vaccinating domestic animals (dogs).

Uganda-specific notes

Rabies is endemic, dogs are the main reservoir. Access to timely and complete PEP (vaccine + RIG) can be challenging and costly, especially outside major centres. Clinical rabies cases require careful management to ensure staff/caregiver safety and provide compassionate palliative care.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 2, Section 2.3.5 (Clinical Disease)

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 1, Section 1.2.1.3 (Animal Bites - PEP)

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