SALMONELLOSIS-FOWL TYPHOID

Etiology: Salmonella gallinarum

Occurrence and Economic Significance

Potentially world-wide in distribution and frequently encountered in subsistence or semi- commercial flocks. The disease is responsible for serious economic losses in commercial units in organized poultry industries in endemic areas.

Transmission

Vertical and lateral transmission occurs as for S. pullorum.

Clinical Signs

Acute onset of fowl typhoid occurs in susceptible flocks which are exposed to infection. Ascending morbidity and corresponding mortality may attain 5 – 10% within a week. No characteristic prodromal signs are noted.

• Diarrhea
• Depression
• Decline in egg production

Pathology

• Gross enlargement of the spleen and liver
• Oophoritis (inflammation of the ovary)
• Ovarian regression
• Peritonitis may be present in chronic cases

Diagnosis

Isolation and identification of S. gallinarium is required to confirm the diagnosis. The rapid whole blood plate agglutination test will demonstrate antibodies approximately 2 weeks after infection and can be used to screen flocks for reactors.

Treatment

Treatment is inappropriate for breeding flocks, which should be depleted.

Commercial laying flocks may be salvaged under specific conditions by administering furazolidone or tetracycline in feed at 400 g/ton, for two weeks, where permitted. Eggs should not be marketed during medication or the subsequent withdrawal period.

Prevention

Appropriate biosecurity measures should be implemented as for S. pullorum infection, to prevent introduction of infection.

Administration of live 9R strain S. gallinarum vaccine during the rearing period will eliminate outbreaks of clinical disease. Bacterins are generally ineffective in preventing fowl typhoid.