- Zulfiqar A Bhutta, Husein Lalji Dewraj professor and chairman (email@example.com)1
- 1 Department of Paediatrics and Child Health, Aga Khan University, Karachi, Pakistan
- Accepted 5 June 2006
Although advances in public health and hygiene have led to the virtual disappearance of enteric fever (more commonly termed typhoid fever) from much of the developed world, the disease remains endemic in many developing countries. Typhoid fever is caused by Salmonella enterica serovar Typhi (S typhi), a Gram negative bacterium. A similar but often less severe disease is caused by S paratyphi A and, less commonly, by S paratyphi B (Schotmulleri) and S paratyphi C (Hirschfeldii). The common mode of infection is by ingestion of an infecting dose of the organism, usually through contaminated water or food. Although the source of infection may vary, person to person transmission through poor hygiene and sewage contamination of water supply are the most important.
Have the epidemiology and burden estimates of typhoid changed?
Few established surveillance systems for typhoid exist in the developing world, especially in community settings, so the true burden is difficult to estimate. This is shown by recent revisions in the global estimates of the true burden of typhoid. In contrast to previous estimates, which were 60% higher,1 investigators from the US Centers for Disease Control and Prevention estimate that there are 21.6 million typhoid cases annually, with the annual incidence varying from 100 to 1000 cases per 100 000 population.2 The global mortality estimates from typhoid have also been revised downwards from 600 000 to 200 000, largely on the basis of regional extrapolations.2 Recent population based studies from South Asia suggest that the incidence is highest in children aged less than 5 years, with higher rates of complications and hospitalisation, and may indicate risk of early exposure to relatively large infecting doses of the organisms in these populations.3–5 These findings contrast with previous studies from Latin Americaw1 and Africa,w2 which suggested that S typhi infection caused a mild disease …