Colibacillosis :

      Colibacillosis is an infectious disease caused by bacterium E. coli and is seen in poultry flocks worldwide.

• coli can cause an infection under skin ( cellulitis ) and is commonly associated with respiratory disease in birds; leads to septicemia and death.
• Primarily affects broiler chicken between the ages of 4-6 weeks.

Etiology :

Avian pathogenic E. coli

     [ gram -ve , rod shaped , non-acid fast , non- spore forming bacillus ]

• Many strains are motile peritrichous flagella.
• coli are classified into four major group on basis of their pathogenicity :

a. Entero toxigenic E. coli

b. Entero invasive E. coli

c. Entero pathogenic E. coli

d. Enterohemorrhagic E. coli

Transmission :

• Fecal contaminated feed and water
• Eggshell contamination at cloaca by excreta is also common with the bacteria present in the nest.
• A respiratory route may be involved due to contaminated dust in poultry houses.
• Ovarian route, with birds shading coli through uterine infection. Infected breeder hens transmit it to newly hatched chicks.
• Contaminated feed is a frequent cause of transmission

Pathogenesis :

Bacteria enter into birds through respiratory tract , skin trauma , cloaca , navel , etc

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1. coli can extend locally or gain access to bloodstream

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               Occurs coli septicaemia

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               Acute septicaemia to death

• Infection can also extend to serosal surfaces to cause subacute polyserositis and chronic granulomatous.

Major clinical and postmortem findings that are caused by E. coli :

1. Colisepticemia
2. Coligranuloma (Hjarre’s dis.)
3. Air sac dis.
4. Coliform cellulitis(inflammatory process)
5. Swollen-head Syndrome (SHS)
6. Coliform peritonitis
7. Coliform Salpingitis
8. Coliform osteomyelitis/synovitis
9. Coliform panophthalmitis
10. Coliform omphalitis/Yolk sac infection

Signs :

• Respiratory distress
• Reduced appetite
• Poor growth
• Decrease in production