Overview

Typhoid fever is a bacterial infection that can spread throughout the body, affecting many organs. Without prompt treatment, it can cause serious complications and can be fatal.

It's caused by a bacterium called Salmonella typhi, which is related to the bacteria that cause salmonella food poisoning.

Typhoid fever is highly contagious. An infected person can pass the bacteria out of their body in their stools (faeces) or, less commonly, in their urine.

If someone else eats food or drinks water that's been contaminated with a small amount of infected faeces or urine, they can become infected with the bacteria and develop typhoid fever.

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Typhoid fever

Symptoms

Common symptoms of typhoid fever include:

If typhoid fever isn't treated, the symptoms will continue to get worse over the following weeks and the risk of developing potentially fatal complications will increase.

Read more about the symptoms of typhoid fever and the complications of typhoid fever.

Causes

Typhoid fever is caused by a type of bacteria called Salmonella typhi.

This isn't the same bacteria that cause salmonella food poisoning, but the two are related.

The Salmonella typhi bacteria will be in the stools (poo) of an infected person after they've been to the toilet. If they don't wash their hands properly afterwards, they can contaminate any food they touch. Anyone else who eats this food may also become infected.

Less commonly, the Salmonella typhi bacteria can be passed out in an infected person's urine. Again, if an infected person handles food without washing their hands properly after urinating, they can spread the infection to someone else who eats the contaminated food.

In parts of the world with poor sanitation, infected human waste can contaminate the water supply. People who drink contaminated water or eat food washed in contaminated water can develop typhoid fever.

Other ways typhoid fever can be contracted include:

  • using a toilet contaminated with bacteria and touching your mouth before washing your hands
  • eating seafood from a water source contaminated by infected faeces or urine
  • eating raw vegetables that have been fertilised with human waste
  • contaminated milk products
  • having oral or anal sex with a person who's a carrier of Salmonella typhi bacteria
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Diagnosis

A diagnosis of typhoid fever can usually be confirmed by analysing samples of blood, stools or urine. These will be examined under a microscope for the Salmonella typhi bacteria that cause the condition.

The bacteria aren't always detected the first time, so you may need to have a series of tests.

Testing a sample of bone marrow is a more accurate way of diagnosing typhoid fever. However, getting the sample is both time-consuming and painful, so it's usually only used if other tests are inconclusive.

If typhoid fever is confirmed, other members of your household may also need to be tested, in case you've passed the infection on to them.

Complications

Complications caused by typhoid fever usually only occur in people who haven't been treated with appropriate antibiotics or who weren't treated straight away.

In such cases, about 1 in 10 people experience complications, which usually develop during the third week of infection.

The two most common complications in untreated typhoid fever are:

  • internal bleeding in the digestive system
  • splitting (perforation) of a section of the digestive system or bowel, which spreads the infection to nearby tissue

These are described in more detail below.

Internal bleeding

Most internal bleeding that occurs in typhoid fever isn't life-threatening, but can make you feel very unwell.

Symptoms include:

  • feeling tired all the time
  • breathlessness
  • pale skin
  • irregular heartbeat
  • vomiting blood
  • passing stools that are very dark or tar-like

A blood transfusion may be required to replace lost blood, and surgery can be used to repair the site of the bleeding.

Perforation

Perforation is potentially a very serious complication. This is because bacteria that live in your digestive system can move into your stomach and infect the lining of your abdomen (the peritoneum). This is known as peritonitis.

Peritonitis is a medical emergency, because the tissue of the peritoneum is usually sterile (germ-free). Unlike other parts of the body, such as the skin, the peritoneum doesn't have an inbuilt defence mechanism for fighting infection.

In peritonitis, the infection can rapidly spread into the blood (sepsis), before spreading to other organs. This carries the risk of multiple organ failure. If it isn't treated properly, it may result in death. The most common symptom of peritonitis is sudden abdominal pain that gets progressively worse.

If you have peritonitis, you'll be admitted to hospital, where you'll be treated with antibiotic injections. Surgery will then be used to seal the hole in your intestinal wall.

Risks

Typhoid fever is most common in parts of the world that have poor sanitation and limited access to clean water (at the bottom of this page is a list of high-risk areas).

Worldwide, children are thought to be most at risk of developing typhoid fever. This may be because their immune system (the body's natural defence against infection and illness) is still developing. However, children with typhoid fever tend to have milder symptoms than adults.

The areas with the highest rates of typhoid fever are:

  • the Indian subcontinent
  • Africa
  • South and South East Asia
  • South America
  • the Middle East
  • Europe
  • Central America
Self-help

In the UK, two vaccines are available that can provide some protection against typhoid fever. These involve either having a single injection or taking three capsules over alternate days.

Vaccination is recommended for anyone planning to travel to parts of the world where typhoid fever is widespread (see below). It's particularly important if you're planning to live or work closely with local people.

However, as neither vaccine offers 100% protection, it's also important to follow some precautions when travelling. For example, you should only drink bottled or boiled water, and avoid foods that could potentially be contaminated.