Identity

An acute bacterial respiratory disease of chickens caused by Avibacterium paragallinarum. It strictly targets the upper respiratory tract, causing severe acute inflammation, facial swelling, and a significant drop in egg production.

Overview

Infectious Coryza is a high-priority, globally distributed bacterial pathogen affecting multi-age commercial layer and breeder facilities. The fastidious bacterium releases endotoxins that induce acute inflammation of the nasal passages and infraorbital sinuses. It causes severe egg drops, growth retardation, and facial swelling. Recovered birds remain lifelong subclinical carriers, making "all-in, all-out" management essential. Control combines trivalent inactivated bacterin vaccines and the administration of water-soluble antimicrobials guided by SVTG guidelines.

Structured Facts

Classification

Bacterial > Infectious Pathogen

Epidemiology

• Prevalence in India: High commercial impact
• Severity: High
• Affected Species: Poultry (Pullets and Layers)
• Affected Age: Birds > 14 weeks of age
• Transmission: Horizontal via direct contact, airborne droplets, and contaminated drinking water
• Mortality: < 5% (uncomplicated)
• Morbidity: 80% to 100%
• Economic Importance: High (due to feed intake drop and egg drop of 10-40%)

Clinical Signs

• Early/Intermediate: Short incubation (24-48 hrs). Rapid onset of sneezing, serous-to-mucoid nasal discharge, severe drop in feed intake.
• Advanced: Marked bilateral facial swelling (infraorbital sinuses and eyes), extending to wattles in males. Drop in egg production (10-40%). Targets Upper Respiratory system.
• Postmortem Findings: Acute catarrhal inflammation of nasal passages, with infraorbital sinuses containing thick mucoid-to-caseous exudate. Subcutaneous edema of face/wattles.

Diagnosis

• Field Diagnosis: Acute facial swelling and foul-smelling nasal discharge in laying flocks
• Laboratory Tests: Isolation on blood agar cross-streaked with Staphylococcus aureus (satellite growth of dew-drop colonies), PCR, serology
• Differential Diagnosis: Fowl Cholera, Mycoplasmosis, Swollen Head Syndrome

Treatment

• Immediate Actions: Isolation; avoid mixing age groups (all-in, all-out)
• Medicines: Sulfadimethoxine, Erythromycin
• Withdrawal: Subject to DAHD/SVTG guidelines
• Veterinary Intervention: Yes (antimicrobials per SVTG)

Prevention

• Vaccination: Coryza (Trivalent) Inactivated Bacterin Vaccine (Subcutaneous / Intramuscular injection at 10-12 weeks, boosted at 16-18 weeks)
• Biosecurity: Mitigated by standard Biosecurity Protocols
• Farm Management: "All-in, all-out" system to prevent carrier transmission

Quantitative Data

• Morbidity Rate: 80% to 100%
• Mortality Rate: < 5% (uncomplicated)
• Egg Production Drop: 10% to 40%
• Incubation Period: 24 to 48 hours

Relationships

• Vaccines: Coryza (Trivalent)
• Medicines: Sulfadimethoxine, Erythromycin
• Management: Biosecurity Protocols, All-in All-out
• Indicators: Feed Intake