Animals, humans, environment

Salmonella can be introduced into the poultry production chain, processing plant or feed mill at any point by animals (e.g wild birds), humans and the environment. Vaccinating chickens will protect them against infection.

Rodents, wild birds and insects

  • Rodents carry Salmonella between flocks and contaminate feed stores.
  • Wild birds may be infected or carry Salmonella bacteria on their feet.
  • Domestic flies and beetles can transmit SalmonellaSalmonella can also be transmitted vertically to the larvae. Infection can thus be carried to subsequent flocks.

Vaccinating poultry will protect against infection at all points during production.

Control measures

  • Adequate rodent control at all stages of poultry production and feed manufacture.
  • Feed stores and houses should be proofed against wild birds and rodents.


  • Salmonella can be carried on clothing and equipment.
  • People may also be asymptomatic carriers and shed the bacteria. This may cause infection of the chickens, contamination of feed or contamination of poultry products.

Control measures

  • Monitoring of personnel for the presence of Salmonella carriers may be necessary.
  • Strict biosecurity on the farm.
    • shower and changing room facilities.
    • restriction on the number of people allowed to enter poultry houses.
  • Staff attending poultry should not attend other animals.
  • Education of personnel at all stages of poultry production (to include hand washing).
  • Vaccinating the chickens against Salmonella can prevent infection.


An environment contaminated with Salmonella bacteria is a continuous source for infection and cross-contamination. The bacteria are able to survive for a long time in the environment. Subsequent flocks may be infected if a previous flock was Salmonella-positive.

Control measures

  • Buildings, surfaces and equipment should allow for easy cleaning and disinfection.
  • Swabs should be taken after cleaning and disinfection to check for the persistence of Salmonella.
  • Adequate time should be allowed between flocks if previous flock was Salmonella-positive.

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