Synonyms
Bacillary white diarrhea, fatal septicaemia and baby chick salmonellosis.
Aetiology
The disease is caused by S. pullorum which is a non motile gram negative rod shaped organism antigenically related to S. gallinarum.
Age/host range
The disease affects mainly chickens of under 3 weeks of age, less up to6-8 weeks resistant in adult birds of 3 months and above. Chickens and turkeys are most vulnerable but other species of birds can become infected for example game birds, guinea fowls, sparrows, parrots, ring doves, ostriches and peafowls.
Transmission
-Pullorum is spread primarily through the egg, from hen to chick
-Formite transmission includes by contaminated incubators, hatchers, chick boxes, houses, equipment, poultry by-products, feedstuff and carrier birds
-Cannibalism
-Adult carriers; the organism is released through the faeces which pollutes water and food of Aves.
The Clinical signs
Incubation period is between 5-10 days post infection. Morbidity is 10-80%; mortality is 0-100% and increased in stressed or immunocompromised flocks and may be up to 100% The greatest losses usually occur in the second week after hatching with a rapid decline between the 3rd and 4th week of age.
Clinical signs include
From S. pullorum infected eggs, moribund and dead chicks are observed within a short time after hatching. Chicks that are weak, with depressed appetite, stunted growth followed by death which peaks during the second week of life; the birds also exhibit lassitude, huddling, droopiness, gasping and chalk-white faeces sometimes stained with green bile.
Other signs are ruffled feathers with closed eyes, loud chirping; lameness and survivors become asymptomatic carriers.
With localized infection in the ovary, suboptimal egg production may be the only sign of the disease when adult laying birds are affected.
Post-mortem lesions.
-Chicks that die shortly after hatching are likely to have peritonitis with inflamed unabsorbed yolk sac.
-Congested and enlarged lungs, spleen and liver with grey nodules in lungs, gizzard wall, heart and liver.
-Intestinal inflammation or caecal inflammation with caecal cores.
-Urate crystals in ureters
-Edema of tibiotarsal joints
Diagnosis
Tentative diagnosis is based on characteristic clinical signs and post-mortem lesions. Positive diagnosis is by isolation and recognition of the causative organism. Tube and rapid plate agglutination tests have been the usual serological tests for years.
Differential diagnosis
Typhoid, paratyphoid, paracolon, other enterobacteria, omphalitis.
Treatment
Treatment is not recommended because although treatment will reduce mortality in pullorum disease, it will not eliminate carriers from an infected flock. When treatment is indicated, the following drugs are used—Amoxycillin, furazolidone, sulphonamide that has been potentiated, tetracyclines and fluoroquinolones .
Prevention
Eradication from parent flocks. So as with other salmonellae, recuperated birds are resistant to the effects of infection but may remain carriers. Normally, vaccines are not used as they interfere with serological testing and elimination of carriers. Spraying eggs with neomycin sulphate prior to incubation is helpful in incubation of pullorum disease.
Management procedures to prevent pullorum disease and fowl typhoid
-Since both diseases are transmitted by eggs, only eggs free of pullorum disease and fowl typhoid should be used in hatcheries.
-Chicken and breeding flock and their progeny should be broadly applied to prevent the introduction of pullorum disease and fowl typhoid.
-Chicks and poults should be obtained from sources free of pullorum disease and fowl typhoid.
-Pullorum free and typhoid free stock should not be mixed with other poultry or confined birds.
-Chicks and poults should be placed in an environment that can be cleaned and disinfected to eliminate any lingering salmonellae from former flock.
-Chicks and poults should receive peletized crumbled feed to minimize the introduction of S.gallinarum and S.pullorum
-The Introduction of these microorganisms should be minimized by the use of a sound biosecurity program; free flying birds/rodents are commonly found to be carriers of other salmonella, so poultry houses should be rodent and bird proofed.
-Insect and pest control is important as they provide a means of survival for salmonella and other avian pathogens.
-Portable drinking water must be used or chlorinated water be provided. Mechanical carrier of the organism include foot wear, clothing of humans as well as poultry equipment trucks, crates etc. Precaution should be taken to prevent the introduction of the S. pullorum and S. gallinarum.
-Proper disposal of dead birds is essential.
-Elimination of carriers can be done by early fields testing results to remove reactors.