Animal health: Salmonellosis

Salmonellosis causes diarrhea and blood poisoning in animals and is an important cause of infections in people.

Cause

There are several thousand types of Salmonella bacteria, but only a few types cause disease. Some animals can carry the bacteria without getting sick, making control of the disease difficult (Figure 1). The presence of stressors, such as transportation, pregnancy, changes in feed and the presence of other diseases, will influence whether an infected animal becomes ill or not. Very young and old animals are most susceptible to the disease.

Sources of human salmonella infection include infected animals, contaminated food and the environment. In the environment, the bacteria can survive and multiply for a long time.

Pets and reptiles, such as turtles, lizards or snakes, can also be a source of Salmonella infection in humans (Figure 2).

Clinical signs

Salmonellosis causes fever, diarrhea or bloody diarrhea, either as a sudden outbreak or an ongoing condition. The diarrhea may have a foul smell and can be severe enough to cause abdominal pain and dehydration in the animal. In younger animals, it usually causes a blood-borne infection that appears as depression, difficulty breathing and weakness followed by death. The skin on the tips of the ears, tails and limbs may turn a dark colour and die. Sometimes in pigs, the bacteria damage the lining of the intestine, and the pig will have difficulty passing manure. A cow may lose her pregnancy.

Treatment

Your veterinarian can diagnose and assist with a treatment plan. The earlier animals are treated, the better. However, use caution if using antibiotics to treat salmonellosis as this can alter the normal bacteria in the gut and can lead to the development of resistant strains of Salmonella. Severely dehydrated animals may need fluid replacement. Isolate sick animals and treat them separately from the rest of the herd.

Prevention and management

Good sanitation and disinfection are required to keep salmonellosis under control. Source animals from farms that are free of salmonellosis. On the farm, prevent manure contamination of feed and keep wildlife such as birds away from your animals.

Transmission to humans

Humans become infected through direct contact with infected animals and people, by eating contaminated food or drinking contaminated water. Symptoms include sudden onset of fever, headache, diarrhea, stomach cramps, nausea and sometimes vomiting. Always wash your hands after handling your animals or pets, and especially after cleaning out aquaria and terraria. Do not keep reptiles in the same household as the young, the elderly or people with weakened immune systems. Always handle and cook eggs, meat and dairy products properly.

Reporting

Veterinary laboratories in Ontario and veterinarians who use a laboratory outside of Ontario must report diagnoses of salmonellosis to the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). OMAFRA will monitor for trends in salmonellosis and will work with public health officials to control the disease.

For more information on animal health, go to Ontario.ca/animalhealth.