B313 - PULLORUM DISEASE
| Nature of the disease |
| Pullorum disease is the infection of poultry by
Salmonella pullorum. The infection is very similar to condition caused by
S. gallinarum. |
| Classification |
| OIE, List B disease |
| Susceptible species |
| Chicken and turkeys, S. pullorum is a specific
bacteria but it can affect other bird
species. |
| Distribution |
| Worldwide, nowadays it seems to be absent from the
Pacific region. |
| Clinical signs |
The incubation period is usually a few days. The
disease affects almost exclusively young birds which exhibit:
- Peracute infection with sudden death,
- Acute infection in first few days:
- Weakness,
- Somnolence,
- Anorexia,
- Poor growth,
- Pasting of vent with chalky white excreta,
- Death.
- In older birds:
- Lethargy,
- Huddling under brooders,
- Wing droop,
- Dyspnoea.
- Growth retardation and poor feathering of survivors.
|
| Post-mortem findings |
Gross lesions may be seen in chronic disease, but are
usually absent in peracute disease. When present the following may be seen:
- Enlargement and congestion of liver, spleen and kidneys,
- Yolk sac retention, with yolk appearing creamy or caseous,.
- Lung and heart may have white nodules, pericardium may be thickened, with
yellow or fibrinous exudate,
- Gastro-intestinal tract - may have white nodules on the gizzard, caeca,
large intestinal wall.
- Caseous cores may be seen in the caeca.
- Joints may be swollen with yellow viscous fluid.
|
| Differential diagnosis |
|
|
| Specimens required for diagnosis |
| Tissue and faeces samples can be submitted for
bacteria identification through culture or genetic techniques.
Serological tests are satisfactory for establishing the presence and
estimating the prevalence of infection within a flock.
|
| Transmission |
| From infected birds, their faeces and their eggs.
Ingestion of contaminated food, water or bedding, and contact transmission; also
mechanical spread by humans, wild birds, mammals, flies, and on trucks, feed
sacks. May occur in newly-hatched birds due to trans-ovarial transmission.
|
| Risk of
introduction |
| Pullorum could be introduced by importation of live
infected chicken, hatching eggs. The bacteria can also be found in poultry meat
but contamination of poultry flocks through this route is at low risk.
|
| Control
/ vaccines |
| Live and inactivated vaccines are available for fowl
typhoid in some countries.
If introduced control should focus on eradication of the disease through
isolation and destruction of contaminated flocks, proper disposal of carcasses
and disinfection of fomites.
|
| References |
- Pullorum disease, In Merck Veterinary Manual, National Publishing
Inc. Eight ed, 1998, Philadelphia, p. 1960-1962
- Office International des Epizooties, 2002
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