Typhoid is an infection caused by the bacterium Salmonella typhimurium (S. typhi). The bacterium lives in the intestines and bloodstream of humans. It spreads between individuals by direct contact with the faeces of an infected person.  No animals carry this disease, so transmission is always human to human. If untreated, around 1 in 5 cases of typhoid can be fatal. With treatment, fewer than 4 in 100 cases are fatal. S. typhi enters through the mouth and spends 1 to 3 weeks in the intestine. After this, it makes its way through the intestinal wall and into the bloodstream.

From the bloodstream, it spreads into other tissues and organs. The immune system of the host can do little to fight back because S. typhi can live within the host’s cells, safe from the immune system. Typhoid is diagnosed by detecting the presence of S. typhi via blood, stool, urine, or bone marrow sample.

Fast facts on typhoid

• Typhoid is a common bacterial infection in countries with low incomes.
• Untreated, it is fatal in around 25 per cent of cases.
• Symptoms include a high fever and gastrointestinal problems.
• Some people carry the bacteria without developing symptoms
• Most cases reported in the United States are contracted overseas
• The only treatment for typhoid is antibiotics

Treatment

The only effective treatment for typhoid is antibiotics. The most commonly used are ciprofloxacin (for non-pregnant adults) and ceftriaxone. Other than antibiotics, it is important to rehydrate by drinking adequate water. In more severe cases, where the bowel has become perforated, surgery may be required