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Infectious Bronchitis (IB)

Infectious Bronchitis is a highly contagious viral disease of chickens caused by an avian coronavirus (Infectious Bronchitis Virus), which primarily affects the respiratory system of chickens, leading to coughing, sneezing, nasal discharge, and reduced activity. Certain strains can also affect the kidneys and reproductive tract, causing wet droppings, drops in egg production, and poor shell quality.

There is no specific antiviral treatment; care is supportive and focuses on stress reduction, warmth, hydration, pain management, and controlling secondary bacterial infections. Prevention relies on vaccination, strong biosecurity, and limiting movement between flocks.

Affected Birds

  • Chickens

Clinical Signs

  • Respiratory signs: coughing, sneezing, tracheal rattles, nasal discharge, watery eyes

  • Reduced activity: lethargy, huddling, reduced appetite

  • Egg-related changes: sudden drop in lay, thin-shelled or misshapen eggs, watery albumen

  • Wet droppings: Certain strains particularly affect the kidneys or reproductive tract.

  • Variable mortality, usually low unless complicated by secondary infections

  • Slow growth in young birds

Transmission

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1. Aerosol / respiratory droplets

IB spreads through the air via coughing, sneezing, dust, and air movement. This is the fastest and most important transmission route.

2. Direct bird contact

Close contact allows rapid spread, as infected birds shed large amounts of virus.

3. People & equipment (biosecurity spread)

The virus is easily carried on hands, clothing, footwear, crates, feeders, drinkers, egg trays, and vehicles moving between flocks.

4. Contaminated environment

IB is shed in droppings and survives in litter, dust, and organic material, allowing ongoing spread within a flock.

5. Mechanical carriers

Wild birds, rodents, and insects can mechanically carry the virus on their bodies even though they are not infected.

Diagnosis

  • 1. Clinical Suspicion

    IB is suspected when birds show sudden-onset respiratory signs, reduced egg production, or misshapen/poor-quality eggs, especially when the problem spreads rapidly through the flock.

    2. Laboratory Testing

    Definitive diagnosis requires testing:

    • PCR testing on swabs (choanal cleft, trachea, or cloaca) to detect IBV genetic material
    • Virus isolation in specialised laboratories
    • Serology (ELISA) to measure rising antibody levels between acute and convalescent samples
    • Post-mortem findings, such as swollen kidneys or mucus-filled trachea, can support diagnosis

    3. Differentials to Rule Out

    Other conditions that look similar and must be excluded include:

    • Mycoplasma gallisepticum
    • Infectious laryngotracheitis (ILT)
    • Avian influenza
    • Newcastle disease
    • Colibacillosis (secondary infection)

    Treatments

    • Close-up of a brown chicken with a blurred green background

      For infectious bronchitis (IB) in chickens, there is no direct cure. Treatment is supportive and preventative, aimed at reducing losses and secondary complications.

      1. Supportive care (the mainstay)

      • Keep birds warm, dry, and stress-free
      • Ensure easy access to clean water and quality feed
      • Reduce dust and ammonia (good ventilation without chilling)

      2. Manage secondary infections

      • IB damages the respiratory tract, making birds prone to secondary bacterial infections (e.g. E. coli)
      • Antibiotics may be used only to control secondary bacterial infections, they do not treat the virus itself. Use should be targeted and responsible.

      3. Hydration & electrolyte/vitamin support

      • Electrolytes encourages drinking. These help birds cope with fever, reduced intake, and stress
      • Using a good multivitamin that contains A, E, and C are commonly used during outbreaks to support mucosal and immune health.

      4. Flock management

      • Isolate affected birds where possible
      • Limit movement of people, birds, and equipment
      • Expect reduced production, especially egg quality, during and after infection

    Prevention

    • Vaccination is the only effective control strategy

      • Live and/or inactivated vaccines are used depending on strain and system
      • Proper vaccine choice and timing are critical
      • Biosecurity is essential even in vaccinated flocks

    How to Give Supportive Care

    • Poultry Supportive care guide
    Read it Here

    Supplements

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