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Reporting Obligations

Individuals who have or may have salmonellosis shall be reported to the local Health Unit.

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Aetiologic Agent

Salmonellosis is caused by the bacterium, Salmonella, a Gram-negative, non-spore forming bacillus that has over 2,500 serotypes, belonging to the Enterobacteriaceae family.

The new nomenclature for Salmonella is Salmonella enterica subsp enterica. Serovars include Typhimurium, Enteriditis, etc.

Clinical Presentation

Salmonellosis commonly manifests as sudden onset of diarrhea, which may be bloody, abdominal pain, fever, nausea, and vomiting. The illness usually lasts 4 to 7 days, and most individuals recover without treatment. Diarrhea may lead to dehydration, which can be severe among the young, the elderly and those with impaired immune systems. Severity of the disease is related to serotype, number of organisms ingested and host factors; severity can be increased when the organism is resistant to antimicrobial agents used to treat the patient.

Salmonella infections can spread to urine, blood, bones, joints, the brain, or the nervous system, or other internal organs causing symptoms related to that part of the body or system. These extra-intestinal infections can have long-term effects, may be severe, and are potentially fatal. Death is uncommon, except among the very young, the frail elderly, and the immunosuppressed.

Modes of Transmission

Salmonella live in the intestines of humans and other animals (swine, cattle, rodents, dogs, cats, hedgehogs), including reptiles, amphibians, poultry and other birds. Infection is acquired by direct or indirect contact with infected animals or their environment.

The predominant mode of transmission is through the ingestion of contaminated food, often times of animal origin. The most common food sources include raw and undercooked poultry and poultry products (e.g. frozen breaded chicken products), unpasteurized/raw milk and milk products, eggs, meat and meat products, processed foods and produce.

Salmonella has also been found in pet food and treats.

Contaminated water is also an important mode of transmission, especially in areas where drinking water supplies are not disinfected.

Fecal-oral transmission from person-to-person has also been observed when diarrhea is present, especially in institutional settings. Infants and stool incontinent adults pose a greater risk of transmission than do asymptomatic carriers.

Incubation Period

From 6–72 hours, usually about 12–36 hours. Longer incubation periods of up to 16 days have been documented, and may not be uncommon following low-dose ingestion.

Period of Communicability

The period of communicability extends throughout the course of infection and carriage. A temporary carrier state may continue for months, especially in infants. Depending on the serotype, approximately 1% of infected adults and 5% of children younger than 5 years, may excrete the organism for up to 1 year. Antimicrobial therapy can prolong excretion.

Risk Factors/Susceptibility

Susceptibility is general and usually increased by achlorhydria, antacid treatment, gastrointestinal surgery, prior or current broad-spectrum antibiotic therapy, neoplastic disease, and other immunosuppressive conditions including malnutrition. Immunosuppressed patients, infants and the elderly are at increased risk for invasive infection.

Diagnosis and Laboratory Testing

Diagnosis is made through the isolation of Salmonella organisms from stool, rectal swabs, urine, blood or any other sterile site.

Specimens are accepted only from health units at the Public Health Lab. If you are a clinician, please use a community laboratory to perform your testing. Confirmation and speciation performed at Public Health Lab.

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Treatment and Case Management

Decisions regarding treatment of individual cases are at the discretion of the attending clinician. For uncomplicated enterocolitis, treatment is generally supportive (e.g., rehydration and electrolyte replacement as needed). Evidence suggests that antibiotic therapy does not shorten the duration of disease, can prolong the duration of fecal excretion, may not eliminate the carrier state, and may lead to resistant strains or more severe infections. Antibiotic treatment may be considered for certain groups, including infants up to 2 months, the elderly, the debilitated, those with sickle cell disease, persons with HIV, or patients with continued high fever or manifestations of extraintestinal infection.

Inform patients that symptomatic cases will be excluded from food handling, from attending or working in day nurseries, from direct care of infants, elderly, immunocompromised and institutionalized patients until symptom free for 24 hours, or symptom free for 48 hours after discontinuing use of anti-diarrheal medication.

Patient Information

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Additional Resources

Public Health Agency of Canada. “Salmonella Fact Sheet”. 22 Nov 2012.

Ministry of Health and Long-Term Care, Public Health Division. “Did you know that contact with amphibians, reptiles, and feeder rodents can make you sick with Salmonella?”


Ministry of Health and Long-Term Care. Infectious Diseases Protocol, 2022.