Who's affected?
Typhoid fever is most common in parts of the world that have poor sanitation and limited access to clean water.
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.
But children with typhoid fever tend to have milder symptoms than adults.
Typhoid fever is uncommon in the UK, with an estimated 500 cases occurring each year.
In most of these cases, the person developed the infection while visiting relatives in Bangladesh, India or Pakistan.
But you're also at risk of developing the infection if you visit Asia, Africa or South America.
Find out where typhoid fever is most common