Pullorum disease is an acute or chronic infectious, bacterial disease affecting primarily chickens and turkeys, but most domestic and wild fowl can be infected. The cause is a bacterium named Salmonella Pullorum.

This organism is most commonly egg transmitted, but it may also occur by these methods:

• Infected hen to egg, egg to chick, or chick to chick in incubator, brooder, or house,
• Mechanical transmission (carried around on clothes, shoes or equipment),
• Carrier birds (apparently healthy birds shed the disease organisms),
• Contaminated premises (from previous outbreaks).

Disease organisms could enter the bird through the respiratory or digestive systems. This means that eggs in the incubator can be infected by another egg carrying the disease.

Pullorum disease is highly fatal to baby chicks, but mature birds are more resistant. Young birds can die after hatching without showing any signs. Most small outbreaks occur in birds that are under three weeks of age. Mortality in such outbreaks may approach 90% if untreated. Survivors are usually stunted and do not grow to their full potential. Infection in young birds may be indicated by droopiness, ruffled feathers, a chilled appearance with birds huddling near a source of heat, labored breathing, and presence of a white diarrhea with a "pasted-down" appearance around the vent. The white diarrhea symptom instigated the term "bacillary white diarrhea" that was commonly associated with this disease at one time.

Diagnosis in young birds is made by isolating the organism in the laboratories so take any suspected birds straight to a vet. In older birds, blood testing may indicate an infection but a positive diagnosis depends upon isolation and identification of the organism by laboratory procedures only.

Complete eradication is the only sound way to prevent pullorum disease. All flocks on the premises should be tested and only pullorum-free flocks used as a source of hatching eggs.

Treatment is a salvage operation and does not prevent birds from becoming carriers. Consequently, do not keep recovered flocks for egg production. Among the drugs used to treat pullorum disease are furazolidone, gentamycin sulfate, and sulfa drugs (sulfadimethoxine, sulfamethazine, and sulfamerazine).

This is a vast subject and cannot be covered in the article above. It is intended solely as a basic introduction. Here are some books to find out more:

The Merck Veterinary Manual, 6th Edition, Editor: Fraser, C.M. Merck & Co., Inc, Rahway, N.J., U.S.A., 1986, ISBN 911910-53-0
Veterinary Medicine - Eighth Edition, Radositis, O.M., Blood, D.C., and Gay, C.C. Balliere Tindal, London, U.K., 1994, ISBN 0 7020 1592 X
Poultry Diseases - Fourth Edition, Jordon, F.T.W. and Pattison, M., Editors: W.B. Saunders Company Ltd., London, 1996 , ISBN 0-7020-1912-7