Identity

A critical bacterial infectious disease caused by APEC. It acts primarily as a secondary opportunistic pathogen that translocates into the bloodstream following mucosal damage, causing acute colisepticemia, severe fibrinous exudation on organs, and high mortality.

Overview

Colibacillosis is a critical, globally distributed bacterial pathogen caused by Avian Pathogenic Escherichia coli (APEC). It possesses extensive virulence factors (fimbrial adhesins, aerobactin) allowing it to evade the host's complement system. In commercial poultry, it frequently manifests after initial respiratory mucosal damage caused by ammonia toxicity or viral infections (NDV, IBV). The bacteria colonize the air sacs and enter the bloodstream, causing a systemic colisepticemia characterized by fibrinous pericarditis and perihepatitis. Management requires rigorous water sanitation, reducing environmental stressors, and targeted antimicrobial therapy guided by susceptibility testing per SVTG protocols.

Structured Facts

Classification

Bacterial > Infectious Pathogen

Epidemiology

• Prevalence in India: Endemic systemic threat
• Severity: Critical
• Affected Species: Poultry
• Affected Age: All classes; broilers between 2 and 10 weeks are highly susceptible
• Transmission: Horizontal via inhalation of contaminated dust, fecal-oral route, contaminated water, or lateral spread from wild animal vectors
• Mortality: 5% to 20%
• Morbidity: Highly variable (1% to 50%)
• Economic Importance: Critical (leading cause of mortality and carcass condemnation)

Clinical Signs

• Early/Intermediate: Depression, huddling, ruffled feathers, dyspnea
• Advanced: Systemic infection (colisepticemia). In layers: sudden death or peritonitis. Targets Respiratory, Cardiovascular, Digestive, and Reproductive systems.
• Postmortem Findings: Classic triad: fibrinous pericarditis, fibrinous perihepatitis, and severe airsacculitis. Also salpingitis, panophthalmitis, synovitis, omphalitis.

Diagnosis

• Field Diagnosis: Fibrinous lesions on liver/heart during postmortem
• Laboratory Tests: Isolation on MacConkey agar (pink, lactose-fermenting colonies), biochemical testing, PCR for APEC-specific virulence genes
• Differential Diagnosis: Salmonellosis, Pasteurellosis, Mycoplasmosis

Treatment

• Immediate Actions: Reduce ammonia and litter moisture
• Supportive Care: Water-Soluble Electrolytes
• Medicines: Enrofloxacin, Neomycin Sulfate, Sulfadiazine-trimethoprim (Administered strictly based on antimicrobial susceptibility testing per SVTG guidelines)
• Withdrawal: Subject to specific antimicrobial withdrawal periods
• Veterinary Intervention: Guided by SVTG protocols

Prevention

• Biosecurity: Water Chlorination (residual chlorine 2-3 ppm), Water Line Sanitation (hydrogen peroxide flush)
• Farm Management: Litter Raking / Tilling to maintain moisture < 25% and reduce ammonia < 20ppm

Quantitative Data

• Morbidity Rate: 1% to 50%
• Mortality Rate: 5% to 20%
• Target Age: 2 to 10 weeks (Broilers)
• Residual Chlorine Target: 2-3 ppm
• Water pH Target: 6.8 - 7.5

Relationships

• Medicines: Neomycin Sulfate, Enrofloxacin, Sulfadiazine-trimethoprim
• Biosecurity: Water Chlorination, Water Line Sanitation
• Predisposing Diseases: Aflatoxicosis, IBD, Infectious Bronchitis Virus, Newcastle Disease Virus
• Predisposing Environmental Factors: Ammonia Toxicity
• Management: Litter Raking / Tilling