1. Basic Facts About Salmonella
What Is Salmonella?
Salmonellosis, or salmonella, is an illness caused by rod-shaped, gram-negative bacteria of the genus Salmonella. The species most often responsible for illness in people is Salmonella enterica (S. enterica), which is found in warm-blooded mammals and the environment. The most common form of salmonellosis is a foodborne illness that results from an infection of the gastrointestinal tract. However, in some parts of the world, the S. enterica serotype Typhi can invade the bloodstream and cause a severe and occasionally life-threatening infection known as typhoid fever.
Symptoms of a foodborne salmonella infection include vomiting, diarrhea, abdominal cramps and fever. They can appear within 12 to 72 hours after infection. In most people, the illness lasts anywhere from four to seven days and usually resolves without treatment. However, the very young, the elderly and those with chronic health conditions or compromised immune systems are more susceptible to infection, and the illness may be more severe, leaving them at risk of dehydration.¹
Symptoms of typhoid fever may not appear until six to 30 days after infection and include weakness, a very high and persistent fever, constipation, headaches and, in some people, a skin rash. Diarrhea is uncommon and vomiting not severe. Symptoms may last for several months if left untreated. It is most common in people who have traveled in countries where hygiene standards are low and where food and drinking water may be contaminated.²
Who Is at Risk?
Anyone is at risk of a foodborne illness caused by salmonella. You are most at risk for salmonellosis if you:3
- are a pregnant woman
- are 60 years of age or older
- are a child under 5 years of age
- have a weakened immune system (cannot easily fight disease)
How Are Salmonella Infections Diagnosed?
Salmonellosis is diagnosed by a health care provider through laboratory testing, usually of a stool sample. If testing shows that you have salmonellosis, further testing can determine the:4
- type of Salmonella bacteria causing the infection
- appropriate treatment
Salmonellosis is a nationally notifiable disease in all provinces and territories. Cases are reported to:5
- provincial or territorial departments of health
- the federal government, if they meet the national case definition
Canada uses different surveillance systems to monitor cases of food-borne illness. These include:5