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Infectious Diseases

Avian Influenza

Influenza infection in humans caused by avian (bird) influenza Type A viruses (e.g., H5N1, H7N9). Primarily a disease of poultry, occasionally transmitted to humans via direct contact with sick birds or contaminated environments. Limited human-to-human spread but potential for pandemic if virus mutates. Notifiable disease.

Also known as: Bird Flu (Human)

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Referral and warning signs

When to refer

IMMEDIATE URGENT REFERRAL/ADMISSION to Designated Hospital (RR) with isolation and intensive care capability for ALL suspected cases of Avian Influenza.

Red flags

  • Fever + Respiratory symptoms + History of poultry contact/exposure in affected area.
  • Severe respiratory distress / Hypoxia.
  • Rapid clinical deterioration.
  • Signs of multi-organ involvement.

Signs and symptoms

  • Incubation period usually 2-5 days (up to 17).
  • Conjunctivitis.
  • Influenza-like illness: Sudden onset fever (>38°C), cough, sore throat, muscle aches (myalgia), headache, fatigue.
  • Lower respiratory tract symptoms common and often severe: Shortness of breath (dyspnea), difficulty breathing, pneumonia, Acute Respiratory Distress Syndrome (ARDS).
  • Gastrointestinal symptoms: Diarrhoea, vomiting, abdominal pain (more common than with seasonal flu).
  • Neurological symptoms (less common): Altered mental status, seizures.
  • Multi-organ failure in severe cases.

Risk factors

  • Direct or close contact with sick or dead infected poultry (chickens, ducks, turkeys).
  • Visiting live poultry markets.
  • Handling or preparing infected poultry for consumption.
  • Exposure to contaminated environments (e.g., farms, markets).
  • Healthcare workers caring for infected patients without adequate PPE (rare human-to-human transmission).

Diagnosis

Clinical assessment

High index of suspicion in patient with severe respiratory illness or influenza-like illness AND relevant exposure history (contact with sick poultry, travel to affected area) within incubation period.

Differential diagnosis

  • Seasonal Influenza.
  • COVID-19.
  • Other causes of severe pneumonia (bacterial, other viral).
  • Malaria (if febrile).
  • Dengue fever.
  • Leptospirosis.

Investigations

  • Specific Laboratory Testing (Requires specialized lab - e.g., UVRI):
  • - RT-PCR: Detection of avian influenza A virus RNA from respiratory specimens (nasopharyngeal swab, throat swab, sputum, bronchoalveolar lavage). Test should specify subtype (e.g., H5N1).
  • - Viral Culture (specialized biosafety labs).
  • - Serology (detecting antibodies - useful retrospectively or for surveillance).
  • Chest X-ray / CT Chest: Shows signs of pneumonia, ARDS.
  • FBC (lymphopenia, thrombocytopenia common), LFTs, Renal function, CK.

Diagnostic criteria

Clinical illness compatible + Epidemiological link (exposure) + Laboratory confirmation (RT-PCR usually).

Management

Non-pharmacological management

  • Urgent Hospitalization (often ICU) with Strict Infection Control.
  • Isolation: Standard, Contact, AND Airborne precautions (negative pressure room ideal, N95/FFP2 respirator minimum).
  • Supportive Care:
  • - Oxygen therapy to maintain SpO2.
  • - Mechanical ventilation for respiratory failure/ARDS (using lung protective strategies).
  • - Fluid management (conservative approach often needed in ARDS).
  • - Management of secondary complications (shock, renal failure, secondary bacterial pneumonia).

Pharmacological treatment

  • Antiviral Treatment: Neuraminidase inhibitors. Start ASAP (ideally within 48h of onset), do not wait for lab confirmation if high suspicion.
  • - Oseltamivir (Tamiflu): Recommended agent. Dose: Adult 75mg PO BID for 5 days (longer course may be needed for severe illness). Pediatric dosing based on weight (see UCG table). (LOC: RR)
  • - Zanamivir (inhaled) or Peramivir (IV) are alternatives (specialist use).
  • Antibiotics: Treat suspected or confirmed secondary bacterial pneumonia.
  • Adjunctive Therapies: Corticosteroids generally NOT recommended unless for other indications (e.g., septic shock, refractory ARDS - specialist decision).

Monitoring

Close monitoring of respiratory status (oxygenation, ventilation), haemodynamics, fluid balance, organ function. Monitor response to antiviral therapy.

Complications

  • Severe pneumonia, ARDS.
  • Respiratory failure.
  • Sepsis, Septic shock.
  • Multi-organ failure (kidney, liver, heart).
  • Encephalopathy.
  • Secondary bacterial infections.
  • Death (high case fatality rate for H5N1).

Prevention

  • Avoid contact with sick or dead birds.
  • Good hygiene practices (hand washing) after contact with birds or environments.
  • Thorough cooking of poultry meat and eggs.
  • Culling of infected poultry flocks.
  • Vaccination of poultry.
  • Surveillance in animal and human populations.
  • Use of appropriate Personal Protective Equipment (PPE) by poultry workers, veterinarians, healthcare workers.
  • Chemoprophylaxis (Post-exposure): Oseltamivir 75mg PO OD for 7-10 days for close contacts of confirmed/suspected human cases or high-risk poultry exposure (public health decision).
  • Pandemic preparedness planning.

Patient education

  • Explanation of the illness and source (birds).
  • Need for hospitalization and isolation.
  • Importance of antiviral medication.
  • Prevention measures for contacts (hygiene, potential prophylaxis).
  • Reporting potential exposures.

Uganda-specific notes

Risk exists due to poultry farming and wild bird populations. Surveillance systems are in place. Suspected cases require immediate notification of District Health Team and MOH, and referral to designated facilities. Strict IPC measures are paramount.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 2, Section 2.3.1

  • Ministry of Health, Uganda - Avian Influenza Preparedness/Response Plans

    (Specific national documents)

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