Typhoid Fever & Paratyphoid Fever

Definition
Typhoid fever is caused by the bacteria, Salmonella typhi, and is transmitted via ingestion of contaminated food and/or water. Paratyphoid fever produces a similar illness and is caused by Salmonella paratyphi. As indicated by its name, fever is most common symptom and the fever can be prolonged, lasting several weeks. Please note that typhoid fever is not typhus fever as these 2 infections are caused by different bacteria. 3-5% of patients who recover from typhoid and paratyphoid fever become chronic carriers of the bacteria, usually in the gastrointestinal tract. Such carriers may spread the disease through the faecal-oral route. Typhoid and paratyphoid fever are also called enteric fever.

Epidemiology
Enteric fever is endemic in areas of poor sanitation, crowding and social chaos such as developing countries. Worldwide, typhoid fever affects more than 21 million people annually with 200,000 people dying from it. In Singapore, 141 cases of typhoid fever were reported in 2012. The majority of the cases were in returning travellers who had acquired the infection overseas, mostly from the regional countries.

Common Pathogens
The primary pathogens of enteric fever are Salmonella typhi and Salmonella paratyphi (types A, B or C).

Clinical

  • Low grade fever in the 1st week which steadily increases in the 2nd week
  • Headache
  • Cough, loss of appetite, rash
  • Abdominal pain and discomfort
  • Diarrhoea or constipation (constipation is more common)
  • There may be transient improvement in symptoms in the 3rd and 4th week for those without complications but the symptoms will then recur
  • From the 3rd week, complications such as delirium, gastrointestinal bleeding and intestinal perforation may occur

Diagnostic Tests
Typhoid fever may be suspected based on your clinical symptoms and your travel history. Diagnosis is usually confirmed by culture of a blood, stool, urine sample. Rarely, a bone marrow sample is required.

Antibody tests and Widal Weil Felix test may be done but there are false positive and false negative test results.

Treatment
With prompt antibiotic treatment, most patients recover fully from typhoid and paratyphoid fever. If there is delay in treatment, there may be life threatening complications such as inflammation of multiple organs, gastrointestinal bleeding and intestinal perforation.

Prevention
You must have good personal hygiene habits to avoid spreading the disease. Another preventive measure to avoid typhoid fever is to get a typhoid vaccination 1 -2 weeks before you travel to high-risk areas. However, the vaccine is not 100% effective and they lose effectiveness after 3 years and require repeat immunisations. On top of the vaccination, you should avoid risky food and drinks. This will help protect from other illnesses like traveller’s diarrhoea, cholera and hepatitis A.

When travelling to high-risk areas, the golden rule is to:

BOIL IT, COOK IT, PEEL IT, OR FORGET IT.

  • If you drink water, buy it bottled or bring it to a boil for 1 minute before you drink it. Bottled carbonated water is safer than uncarbonated water.
  • Ask for drinks without ice unless the ice is made from bottled or boiled water. Avoid popsicles and flavoured ice that may have been made with contaminated water.
  • Choose hot foods and avoid food that has been stored or served at room temperature. Eat foods that have been thoroughly cooked and that are still hot and steaming.
  • Avoid raw vegetables and fruits that cannot be peeled. Vegetables like lettuce are easily contaminated and are very hard to wash well.
  • When you eat raw fruit or vegetables that can be peeled, peel them yourself. (Wash your hands with soap first.) Do not eat the peelings.
  • Avoid foods and beverages from street vendors. It is difficult for food to be kept clean on the street, and many travellers get sick from food bought from street vendors.

It is always a good idea to have good hygiene, especially if you are recovering from typhoid so you can keep others safe:

  • Wash your hands often and thoroughly, especially before eating and after using the toilet
  • Clean household items such as toilets, door handles, telephone receivers and water taps regularly
  • Avoid handling food when you are still recovering
  • Keep personal items such as towels, bed linen and utensils separate until you are fully recovered
 Click here for Appointment