Salmonellosis In Poultry and Control

Salmonellosis is a disease caused by Salmonella bacteria which affects birds of different species and leads heavy losses due to high moralities in the poultry industry worldwide.

Salmonella infections are classified as nonmotile serotypes (S. Pullorum, S. Gallinarum) and the many motile paratyphoid SalmonellaSalmonella is a gram negative bacteria which belongs to the family of Enterobacteriaceae.

Affected flock can experience a morbidity is 10-100% and high mortality,  flocks can be totally wiped out in a farm with poor management.

Transmission can be via oral, navel, horizontal transmission or by faecal-oral contamination.  Salmonella is resistant to a normal climate and it is susceptible to broad spectrum disinfectants. Other predisposing factors include nutritional deficiencies, chilling, inadequate water, poor water quality and other bacterial infections. 

Contamination sources in commercial layers include transmission from breeders, contaminated environments, infected rodents, and contaminated feed, transmission to progeny from breeders is mainly through eggshell contamination. 

Prevention of salmonella in farms is through good biosecurity, maintaining clean environment and purchase of clean chicks.

Spreading of the bacteria can occur through contact with droppings, direct contact with infected birds and feed or water contamination. Affected birds may have greenish-yellow droppings and loss of weight. Flies can spread  the infection, farms or hatcheries with poor biosecurity have high incidence of salmonellosis, birds with weak immune systems, stressed birds and birds that has exposure to wild birds.

 Breeder farms must screen their stock to ensure that they are salmonella free, maintain clean nests, fumigate hatchable eggs, all-in all-out stocking, good feed, proper cleaning and disnfection to eliminate infections in hatcheries, feedmill and rearing farms.

Signs

  • Pasted vent;
  • Ruffled feathers;
  • Lack of appetite;
  • Thirst and Dehydration;
  • Diarrhoea;
  • High morbidity.

Post-mortem

  • Enteritis;
  • Enlarged liver with bronze colour, small necrotic foci, and/or congestion;
  • Unabsorbed yolk in chicks.

Treatment

Wide range of broad spectrum antibiotics has proven effective in the treatment of salmonellosis. , neomycin, tetracyclines, amoxycillin, quinlones, sulphonamides. Good management.

Vaccination has proven effective in prevention of salmonella worldwide and Salmonella Enteritis (SE) bacterins and live attenuated Salmonella Gallinarum vaccines is commercially available; it is used in routine vaccination which serves as a preventive measures to control Salmonella in Breeder and commercial farms.

Salmonella bacterins contain bacteria organisms that were inactivated and suspended in aluminium oxide or any other suitable solution,  after administration it stimulates high level of circulating antibodies in the birds. It’s cheaper to vaccinate than to treat, salmonella vaccine is usually included in Breeder and commercial farms vaccination programmes all over the world.

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