Identity

A high-priority, host-adapted bacterial infectious disease primarily affecting poultry chicks, leading to systemic septicemia, bacillary white diarrhea, and high mortality. Mature birds become chronic asymptomatic carriers with reproductive tract localization.

Overview

Pullorum Disease is an infectious bacterial pathogen of critical importance to hatcheries. The intracellular bacteria survive within host macrophages, causing systemic dissemination in chicks. A single infected hatching egg can contaminate an entire incubator. While clinical disease causes extreme mortality in young chicks (white diarrhea), it remains clinically silent in adults, localizing in the ovaries to ensure vertical transmission. Control relies strictly on eradication via serological blood testing and culling of breeder reactors; treatment is strongly discouraged as it promotes chronic carrier states and antimicrobial resistance.

Structured Facts

Classification

Bacterial > Infectious Pathogen

Epidemiology

• Prevalence in India: High commercial importance; requires regular serological monitoring
• Severity: High
• Affected Species: Poultry (Chickens and turkeys)
• Affected Age: Clinical disease in chicks < 3 weeks; adults act as asymptomatic carriers
• Transmission: Vertical (transovarian via infected eggs), Horizontal (fecal-oral in hatcheries)
• Mortality: 50% to 100% in first three weeks of life
• Morbidity: High in chicks from infected breeders
• Economic Importance: High (Hatchery performance, breeder productivity)

Clinical Signs

• Early/Intermediate: Severe depression, weakness, anorexia, huddling near heat sources
• Advanced: Chalky-white, pasty diarrhea ("bacillary white diarrhea") on vent feathers. Targets Systemic, Enteric, Reticuloendothelial, and Reproductive systems.
• Postmortem Findings: Chicks: Unabsorbed yolk sac, gray-white necrotic nodules in lungs/myocardium/liver/gizzard, cecal caseous cores. Adults: Degenerated, misshapen, cystic ovarian follicles on thin pedicles.

Diagnosis

• Field Diagnosis: High chick mortality with white pasty vents; rapid whole-blood agglutination test in adult carriers.
• Laboratory Tests: Isolation on Brilliant Green or XLD agar, biochemical/serological testing.
• Differential Diagnosis: Fowl Typhoid (Salmonella Gallinarum), Colibacillosis

Treatment

• Immediate Actions: Eradication; remove reactor breeder birds
• Medicines: Treatment discouraged in breeders. Non-breeders may use DAHD approved antimicrobials.
• Withdrawal: Subject to SVTG
• Veterinary Intervention: Strict serological monitoring under DAHD guidelines

Prevention

• Vaccination: None mentioned
• Biosecurity: Mitigated by standard Biosecurity Protocols, Hatchery Hygiene
• Farm Management: Serological monitoring and eradication of carrier breeders

Quantitative Data

• Morbidity Rate: High
• Mortality Rate: 50% to 100% (Chicks)
• Target Age: < 3 weeks (clinical)

Relationships

• Vaccines: None
• Medicines: Discouraged
• Biosecurity: Hatchery Hygiene, Biosecurity Protocols, Whole-blood agglutination testing
• Pathogenesis: Macrophage intracellular survival