Typhoid is caused by bacteria called Salmonella Typhi. Illness is usually characterised by fever, loss of appetite, lethargy and change in bowel habit. Constipation is common, but diarrhoea can also occur. Without treatment the illness can be fatal, with perforation of the gut producing peritonitis or severe bleeding. Transmission is by ingesting contaminated food and water. Contamination is most likely when cooked food is handled or left unrefrigerated.
Typhoid is prevalent in most tropical and subtropical countries in Asia, Africa, the Middle East, Oceania and Central and South America.