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Typhoid Fever (Salmonella Typhi)

Salmonella Typhi bacteria 

Salmonella Typhi (S. Typhi) are bacteria that infect the intestinal tract and the blood. The disease is referred to as typhoid fever. S. Paratyphi bacteria cause a similar, but milder illness, which comes under the same title. Paratyphoid has a shorter duration, generally, than typhoid. S. Typhi and S. Paratyphi are common in many developing countries where sewage and water treatment systems are poor. Most cases reported in BC are among travelers returning from those areas.             

Information for Health Professionals

Salmonella Typhi (S. Typhi) are bacteria which infect the intestinal tract and the blood. The disease is referred to as typhoid fever. S. Paratyphi A, B and C bacteria cause a similar illness which is included under the typhoid heading. However, paratyphoid fever is generally milder and shorter in duration than typhoid fever.

S. Typhi and S. Paratyphi come from the same sources and are common in many developing countries where sewage and water treatment systems are poor. Most cases reported in BC are among travelers returning from those areas.


S. Typhi infection is serious and potentially life-threatening.

S. Typhi may cause:

  • Constipation, more common than diarrhea
  • High fever
  • Headache
  • Fatigue
  • Loss of appetite
  • Dizziness
  • Cough
  • A rash on the trunk

Symptoms start an average of 1 to 2 weeks (range: 3 to 60 days, or longer) after exposure to the bacteria.

If you think you have a S. Typhi infection, see your family doctor for testing, advice and treatment.


S. Typhi is spread by the fecal-oral route. Fecal material from infected humans can get into our mouths in a variety of ways:

  • Consuming contaminated food or drink, prepared by someone who is infected or a carrier (a carrier is someone who has recovered from illness, but continues to carry the bacteria in their body and can infect others)
  • Contact with the feces of infected humans that is not followed by proper hand washing
  • Consumption of ready-to-eat food that has been contaminated by sewage, such as fruit fertilized with night soil, or shellfish from an area contaminated by a sewer outfall

People who have recovered from illness may remain infectious to others (about ten per cent of those recovered may pass the bacteria in their stools or urine for up to three months). Two to five per cent of those ill with typhoid may become carriers (a smaller number with paratyphoid become carriers), passing the bacteria in their excreta for long periods.


The case fatality rate, with treatment, is less than one per cent. Fifteen to 20 per cent may experience a recurrence of illness.


Your doctor can test for an S. Typhi infection through a blood, stool or urine culture.


Antibiotic treatment is required for S. Typhi infections. Without antibiotic treatment, the symptoms may last for months and the fatality rate can be as high as 20%.

Your doctor will decide which treatment is right for you. If your symptoms have already gone away, antibiotics will help clear the bacteria from your system so that you do not pass the infection on to others.

Early treatment with antibiotics reduces the risk of serious illness or death.


If you are a food handler, health care worker or work in or attend a day care, it is possible for you to transmit S. Typhi or S. Paratyphi to others in these settings. You must not work while infected. A public health official will contact you to discuss when you can return to work or day care. See Exclusion of Enteric Cases and their Contacts from High Risk Settings.

Children in day care with fever or diarrhea can be cared for temporarily in an area separate from other children until picked up by their parents. To ensure proper hand washing, children should be supervised by an adult when washing their hands.

Workers and day care attendees can only return when three negative stool samples have been provided, and, if they have traveled to a schistosomiasis-endemic country, and could have been exposed to that, they must also provide a negative urine sample.



Before you travel to a country where S. Typhi is common, consult your doctor or a travel clinic to discuss vaccination against the disease. The vaccine will provide some protection against typhoid fever (it is about 50 to 55 per cent effective). The vaccine is recommended for the following people:

  • Travelers who will have prolonged exposure to contaminated food and water, especially in regions with higher rates of typhoid fever.
  • People living in the same house as a typhoid carrier, or who have sexual contact with a typhoid carrier
  • People who may be exposed to the bacteria at work, e.g. laboratory workers

Vaccination is not routinely recommended for short-term travel to resorts in these areas:

  • Asia
  • Africa
  • Central and South America
  • Middle Easttyphoid vaccination is not necessary for people living in Canada.

Routine Precautions during travel:

Anyone who travels to a country where typhoid fever is common, including Canadian immigrants returning to their country of origin, is at risk of becoming infected with S. Typhi. It is important to practice careful hand washing and be aware of the foods you eat and where you buy them.

The following tips can help you avoid infection:

  • Wash your hands with clean water after using the toilet, before preparing food or drink and before eating
  • Drinking water must be bottled (be careful to buy it from a reputable outlet) or boiled
  • Do not have drinks served with ice unless you are certain the ice was made from bottled or boiled water
  • Do no eat raw fruits and vegetables unless you can peel them yourself
  • Do not consume raw or undercooked fish or shellfish, especially oysters. You can tell food is safe when it is served hot and steaming
  • Do not eat food from street vendors
  • Do not consume unpasteurized dairy products (milk, cheese, yogurt)

Last Updated: March 15, 2012

SOURCE: Typhoid Fever (Salmonella Typhi) ( )
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