Fowl typhoid (avian diptheria, pox, canker)

Occurrence: Worldwide.
Species affected: All.
Age affected: young adults or mature birds.
Causes: Rod-shaped gram negative bacteria- Salmonella gallinarum.
Effects: Elevated temperature to 44-45ºC (109-111ºF), pale combs and wattles, shrunken combs, greenish-yellow diarrhoea, depression and/or anaemia.

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Causes

All birds, especially young adults and mature birds are susceptible to this acute to chronic disease. The causative agent is Salmonella gallinarum, a rod-shaped bacterium which produces no spore or capsule.

Mode of transmission

It is spread by biological vectors and through the egg. The incubation period is 4 to 5 days.
Contaminated feed and H-subscript-2-/subscript-O, fomites (trucks, workers, and equipment, etc.), will transmit the organism. Fomites are inanimate objects which can carry infectious organisms and spread disease.
The organism is species specific (occurs in birds only). Horizontal spread occurs from bird to bird.

Clinical signs

Birds have elevated temperature 109-111oF (44-45oC), pale combs and wattles, shrunken combs, greenish-yellow diarrhoea, depression, and/or anaemia.

Postmortem lesions

Birds have bronze liver and grey foci in lungs and gizzard.
Congested breast muscle, enteritis often with ulceration, mottled swollen spleens and kidney, and thin watery blood are often seen.
Necrotic foci on the liver and heart, misshape rupture ovaries, and peritonitis can occur.

Diagnosis

Laboratory (necropsy, serology, microbial isolation and identification) monitoring is needed for a definitive diagnosis. Culture  Salmonella and determine antibiotic sensitivity. It simulates paratyphoid, pullorum, and cholera.

Treatment & control

Prevention
Depopulate infected flocks. Live vaccine available in some countries. Antibiotics in the water.

Special note

It has been eradicated from most commercial poultry flocks, but is still common in backyard flocks. Still common in parts of the Middle East and Asia. In most countries it is a notifiable disease, no treatment is allowed, only depopulation of the flock.