Synonyms
Coligranuloma (Hjarre’s disease), colisepticaemia, omphalitis, air sac disease, swollen head syndrome, coliform cellulitis, veneral colibasillosis, yolk sac infection, ill navel, mushy chick disease.
Aetiology
E. coli is the causative organism in the family called enterobactericea and genus called Escherichia, a gram negative flagellated(motile), non acid-fast and non spore forming bacillus.
Specie/Age affected
Chickens, turkeys, ducks and pheasants of all ages are affected but the disease is more severe in developing embryo and young chickens.
Predisposing factors for colibacillosis
High stocking density, poor ventilation, Mycoplasma gallisepticum or viral agents like infectious bronchitis virus and Newcastle disease virus and nutritional diseases predispose colisepticaemia.
Transmission
Direct contact with faeces of infected animals or indirect when the faeces from infected birds pollute feed and drinking water; this is possible because the organism is present in intestinal tract and shed in the faeces.
Navels transmission occurs when chicks from dirty hatching eggs or newly hatched chicks are placed in dirty holding boxes.
Eggs that explode in the hatching tray contaminate other eggs in the tray and increase the incidence.
Mechanical transmission by larval and drinking beetles and adult house fly.
The Clinical signs
Incubation period for coilbacillosis is 1-3 days in laboratory infection and 5-7 days in field infection while morbidity varies and mortality is 5-20%.
Clinical signs include
Affected chicks may have external navel infection, large unabsorbed yolk sacs, peritonitis with fetid odour, exudates adhering to the navel and edema of the skin of ventral body area.
Respiratory signs, coughing and sneezing.
Cellulitis noticed when the birds are depressed.
Dejection, reduced appetite.
Poor growth, ruffled feathers
When joints are affected on one leg, there is characteristic hopping and inability to walk.
Post-mortem lesions
Local infection of E. coli such as
Omphalitis or navel infection
Egg yolk peritonitis
Salpingitis with retained yolk
Oophoritis
Cellulitis with chick fibrinous plagues
Enterocolitis : distended and pale intestine particularly the caeca.
Systemic infection of E. coli
Chicks at the first week of life show unabsorbed yolk sac, swollen liver and spleen with typical serofibrinous polyserositis lesions on the peritoneum, pericardium, airsacs and the liver capsule.
In young and adult birds, the liver has a greenish colour mottled with multiple necrotic foci. Pericarditis, perihepatitis, lesions on the air sac, trachea and lungs.
Other lesions are as follows;
Panophthamitis
Sponolytis, synovitis, arthritis, osteomyelitis and osteonecrosis
Coligranuloma: granuloma in the intestine.
Accumulation of exudates between the superficial and deep pectoral muscle.
Bursitis sternalis: inflammation of the sterna bursae.
Diagnosis
Tentative diagnosis is from flock history, characteristic clinical signs and post-mortem lesions. Positive diagnosis is by isolation of the organism on McConkey and blood agar. Majority of the strains are fast lactose fermenting producing brick red colonies on McConkey agar.
Differential diagnosis
Differentiated from acute and chronic infections with Salmonella species.
Acute and chronic salmonellosis
Treatment
The logical approach is to isolate the causative organism and carry out a sensitivity test to choose the most suitable form of therapy. Furazolidone at the level of 0.04% in feed for 10 days or chlortetracycline in water at the rate of 600mg/5 litres for 5 days is usually effective in reducing morbidity and mortality.
Prevention
Good hygiene in management of hatching eggs, hatchery hygiene, good sanitation of house, feed and water. Well-nourished embryo and optimal incubation is essential to maximize day old viability.
Through effective hatchery sanitation, hatchery producers, breeder flock surveillance, proper preincubation and handling of eggs. Mushy chicks should be culled from the hatch and destroyed. If chick mortality exceed 3%, the breeder flock and egg handling procedures should be reviewed.