What is Salmonella?

board of animal health

Reportable Disease of the Month


What is it?

Salmonella are bacteria that can affect the intestinal tract of people and animals. The illness caused from infection with Salmonella is called salmonellosis. The bacteria have been found in mammals, birds, reptiles and amphibians and these animals can carry the bacteria without developing any signs of illness. Salmonella has been found around the world and occurs most frequently where people and livestock reside. Salmonella Enteritidis is a particularly dangerous strain because it is easily transmitted to people if raw or undercooked eggs that contain the bacteria are handled or consumed. This is the reason why it is reportable to the Minnesota Board of Animal Health if identified in chicken egg-layers in Minnesota.

How is it transmitted?

Livestock typically become infected with Salmonella when they consume contaminated feed or water or come in contact with another animal shedding the bacteria. It can also be passed directly to baby animals before they are born or hatched; this is called vertical transmission. The bacteria can also be moved around mechanically by dirty tools, equipment or clothing. Salmonella bacteria are usually transmitted to humans by eating foods contaminated with animal feces. People can be infected by having direct contact with either sick or healthy animals. This usually happens when people have handled animals or have been in the animals’ environment and then accidentally touch their mouths or forget to wash their hands before eating or drinking. Salmonella bacteria survive best in warm and wet environments, but they are also extremely tolerant of many other adverse conditions and can remain infectious for long periods of time in soil and water.

Is there a risk to people?

Yes, according to the Minnesota Department of Health (MDH), up to 925 cases of salmonellosis are reported annually in Minnesota and over 40,000 cases nationwide. People are most commonly infected when they eat contaminated food including eggs, chicken, pork, fruits, sprouts and vegetables and even processed foods such as nut butters, chicken nuggets and frozen pot pies. People can also become sick if they come into contact with farm animals or pets (including reptiles, baby chicks and ducklings), animal feces or animal environments.

What are the clinical signs?

Salmonella bacteria are often carried by animals without any observable clinical signs of infection. Some animals with salmonellosis will become sick and can exhibit signs like diarrhea, dehydration and may even die of the infection before it’s discovered. People who have contracted salmonellosis may develop diarrhea, fever and abdominal cramps within 12 to 72 hours. Symptoms usually last for four to seven days. The elderly, infants, and those with impaired immune systems are more likely to have a severe illness.

How is it diagnosed?

Sick animals should be seen by a veterinarian who can determine the appropriate testing needed to get a diagnosis. The poultry industry in Minnesota conducts routine surveillance for Salmonella by sampling poultry barn environments and submitting samples to the Minnesota Poultry Testing Laboratory for testing. If a person is sick, they should contact their health care provider.

How can it be prevented?

Salmonellosis in animals can be prevented by practicing proper biosecurity. Click here to learn about biosecurity best-practices. Make sure to routinely clean and disinfect barns where livestock are kept and prevent wild birds from entering barns. To protect yourself and your family, you should:

  • Wash your hands thoroughly with soap and water after handling raw foods.
  • Keep your food preparation areas clean.
  • Avoid unpasteurized foods.
  • Cook and store food at appropriate temperatures.
  • Do not put your hands or other items that have come into contact with animals in your mouth after petting or playing with animals.
  • Wash your hands thoroughly with soap and water after touching animals or their environment.
  • Don’t let children younger than age 5, people with weakened immune systems, or older adults touch high-risk animals (like turtles, frogs, chickens, or ducks) or their belongings or habitats.

The MDH has many resources for preventing infection in people available on their website at this link.

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