Causes

• The disease is caused by a Rhabdo virus, which is an RNA single-stranded, bullet-shaped virus measuring 130-300 mm.
• It has an external envelope with a short protrusion.

Source/Reservoir

• The primary reservoirs are infected wild animals from the cat family, such as leopards, foxes, and lions, as well as domestic dogs.
• Humans can become accidental hosts when bitten by these animals.

Transmission

• The virus is transmitted when infected wild animals bite humans directly or indirectly through a domestic dog bite.
• The virus, present in the saliva of infected animals, is passed to humans when it contacts their tissues through a bite.
• Ingestion of infected tissue can also be a mode of transmission.

Occurrence and Importance

• The disease is widespread in many parts of Africa, a region with numerous wild animal reserves.
• Rabies is considered important for several reasons:
  • It can lead to death if not treated immediately.
  • The mortality rate is 100%.
  • Controlling its transmission between wild and domestic animals is difficult.

Incubation Period

• The incubation period ranges from two weeks to one year, with an average of 2 to 342 days.
• The duration depends on:
  • The site of the bite (how far or near it is to the brain).
  • The degree of tissue penetration (whether it’s an abrasion or a deeper wound).

Pathology

• Initial Stage: Upon first contact with nerve tissues at the bite site, the virus persists for 96 hours, during which initial multiplication occurs.
• Spread to CNS: It then spreads through peripheral sensory nerves to the spinal cord and up to the brain, where it multiplies further, exclusively in the grey matter.
• Systemic Spread: From the brain, the virus spreads to other tissues via the autonomic nerves, including the salivary glands, adrenal medulla, kidneys, lungs, liver, skeletal muscles, and skin.
• Infectivity: At this stage, the patient’s saliva and secretions become infected, and any contact can lead to infection.

Clinical Presentations

1. Prodromal Stage

• The onset is sudden, with increasing pain at the wound site.
• Symptoms include headache, high fever, malaise, increasing weakness, anorexia, vomiting, sore throat, and a nonproductive cough.

2. Furious, Excitory Stage

• Characterized by excessive motor activity, overactivity, excitation, agitation, confusion, intense anxiety, and hallucinations.
• Patients may experience muscle spasms, aggressiveness, convulsions, and fits.
• There is a marked hypersensitivity to bright light, loud noise, touch, and genital breeze, as well as high temperatures.
• The patient presents with dilated, regular pupils, lacrimation (tearing), drooling saliva, and excessive sweating.
• The patient may start barking.

3. Paralytic Stage

• This stage involves irritation of the vocal cords and spasms of the pharyngeal muscles.
• Patients experience difficulty swallowing and excessive salivation, which produces foaming.
• Dysphagia (difficulty swallowing) and odynophagia (painful swallowing) are characterized by painful spasms of the swallowing muscles, which can rapidly progress to trunk paralysis of the esophagus, causing the patient to avoid water.
• A hypertonic weakness of the muscles develops, starting near the bite site and spreading, leading to constipation, urine retention, and respiratory failure.
• The patient lapses into a coma, and involvement of the respiratory centers results in apneic death (death from cessation of breathing).
• Note: Survival for more than a week is unlikely, and death follows once a patient begins presenting like a “mad dog”.

Management of Rabies

First Aid Management

• The goal is to remove as much of the viral load as possible from the bite site as soon as possible.
• Local Wound Treatment: Immediately flush and wash the wound for 3 minutes. Scrub the wound with soap and water or “omo” (a brand of detergent), then rinse thoroughly with water.
• The wound should be left open and not sutured.

Hospital Management

• Admission: The patient is admitted to an isolation room in the medical ward or an intensive care unit with dim lighting. They are nursed in a barrier room to prevent contact with their secretions, like vomitus.

• Treatment:

  • Antibiotics: Give systematic antibiotics to prevent wound infection. For example, Inj. Like 1.5mu IM O.D for 5/7 days.
    • Children: 50,000 iu/kg, 1 dose.
    • For those allergic to PPF: Give Metronidazole 400mg every 8 hours or twice daily (B.D) for 5/7 days.
    • Others: Doxycycline 100mg once daily (O.D) for 5 days.
      • Children <8 years: 2mg/kg/dose.
    • CTX (Co-trimoxazole): 960mg twice daily (B.D) for 5 days.
      • Children: 24mg/kg/dose.
  • Note: Metronidazole and doxycycline are contraindicated in pregnancy.
  • Passive Immunization: Immunize the patient with Rabies Immunoglobulin (R.I.G), which are pre-made antibodies injected at the site to neutralize the virus.
  • Active Immunization: Immunize the patient with the rabies vaccine. This is especially for those who present for evaluation months after being bitten.
  • R.I.G. Administration: Carefully infiltrate rabies immunoglobulin in and around the wound. Give any remaining dose via intramuscular (IM) injection at a site distant from the rabies vaccine inoculation. If R.I.G. cannot be given at the start of the vaccine series, it may be given up to seven days later, even if the wound has started to heal.

Immunization Schedules

• Pre-Exposure Prophylaxis (for high-risk individuals): This is for lab staff working with the rabies virus, wildlife wardens, veterinary officers, animal handlers, and tourists.

  • Day 0: 1st dose, 0.5mls IM.
  • Day 28: 2nd dose, 0.5mls IM.
  • Booster Dose: 1 year later, 0.5mls IM.
  • Repeat again after 3 years.

• Post-Exposure Prophylaxis (for patients already bitten):

  • Regimen: 2:1:1.
  • Day 0: Give 2 doses on the deltoid muscle.
  • Day 7: Give 1 dose.
  • Day 21: Give 1 dose.
  • Note: If the patient already has clinical signs, they will be treated in the same way in the ward.

Nursing Care

• Sedation: Sedate the patient with Lagactil (Chlorpromazine/CPZ) 50-100mg, alternated with Diazepam 10mg IV or via nasogastric tube (NGT) every 4 hours. The purpose is to relax the muscles, reduce spasms and convulsions, and a sedation chart should be kept.
• Airway Management: If breathing is a problem due to paralysis of respiratory muscles, perform artificial ventilation with an Ambu-bag. Give oxygen if needed after clearing the airway by suctioning or using gauze to remove saliva, and ensure good head positioning.
• Protection: Nurses and attendants must be protected from the patient’s saliva and body secretions by using masks, gloves, aprons, or goggles.
• Observation: Closely monitor vital signs every 2 to 4 hours to detect cardiac or respiratory failure. Chart and record accurately.
• Rest and Sleep: Keep the patient in a quiet room with dim light. Avoid situations that stimulate spasms, as the patient is hypersensitive to touch, noise, light, temperature, and pain.
• Feeding: This can be done via NGT or IV if the patient is sedated. You can give food per os (by mouth) if the patient is at rabid. If the patient is unconscious, apply nursing care.

Complications

• Cardiac arrhythmias.
• Respiratory failure due to paralysis of intercostal muscles.
• Convulsions and seizures due to infection of the meninges.
• Pneumonia.
• Brain edema and increased intracranial pressure, leading to fits and coma.
• Hyper- or hypopyrexia (abnormally high or low body temperature) due to viral effects on the hypothalamus.
• Diabetes insipidus due to inappropriate secretions of antidiuretic hormones.
• Partial or complete paralysis due to nervous damage.
• Hematemesis (vomiting blood) due to nervous damage.