Typhoid, or typhoid fever, is a systemic infectious disease caused by a bacterium (Salmonella typhi). This pathology mainly affects children.
The transmission of the bacterium takes place from person to person via the faeco-oral route or through the ingestion of contaminated food or water. Contamination occurs when there are poor sanitary conditions. Two to five percent of untreated patients can become chronic carriers, i.e. they eliminate the bacterium in urine and faeces for a period longer than 12 months following the infection. Chronic carriers are the main source of infection.
Symptoms and complications
Typhoid is characterised by severe systemic symptoms. These generally appear 5 to 21 days after ingestion of contaminated food or water. During the first week of illness, fever appears and the bacterium reproduces inside the body. During the second week, abdominal pains begin and small salmon-pink specks may appear on the trunk and abdomen. During the third week, more serious complications can begin, including the appearance of hepatomegaly, intestinal bleeding, intestinal perforation along with bacteremia and peritonitis. These can lead to septic shock with loss of consciousness. These acute complications develop in about 15% of cases. If major complications do not arise, the symptoms gradually subside over a period of about a month.
Impact on the population
Typhoid is an ubiquitous disease, widespread in all countries where sanitary conditions are poor. Each year, there are about 16 million cases globally, causing approximately 600,000 deaths (incidence of 0.3%). In some African and Asian countries, the incidence can reach 1%. In the United States about 300 cases of typhoid fever are reported each year and most of these are in travellers who have visited countries with poor sanitary conditions. In Italy, the incidence equals 2 cases per 100,000 inhabitants per year. It is found more often in the southern regions and in coastal areas, while in other regions the cases are exceptional and usually linked to trips to endemic countries with poor sanitary levels.
If antibiotics are not administered, mortality can reach 10% of cases and is linked to bleeding or intestinal perforation.
Sources / Bibliography
- Parry CM, Hien TT, Dougan G, et al. Typhoid fever. N Engl J Med 2002
- Connor BA, Schwartz E. Typhoid and paratyphoid fever in travellers. Lancet Infect Dis 2005
- Crump JA, Luby SP, Mintz ED. The global burden of typhoid fever. Bull World Health Organ 2004
- CDC Health Information for International Travel 2008 http://wwwn.cdc.gov/travel/yellowBookCh4-Typhoid.aspx
- Organizzazione Mondiale della Sanità – Vaccinazione contro il tifo - Position paper (August 2000) Original English and French versions