An isolate is confirmed as Salmonella when the specific O serogroup has been determined and biochemical identification has been completed

Taxonomy
Family: Enterobacteriaceae

Natural habitats
Humans are the only reservoir for Salmonella typhi, indicating that they are adapted to the human host; healthy carriers have been noted.

Clinical significance
Strains of Salmonella are categorized as typhoidal and nontyphoidal.

S. typhi ► typhoidal infection

Typhoid fever
Caused by Salmonella typhi, is a serious bloodstream infection, common in the developing world. Typhoid fever typically presents which a sustained debilitating high fever and headache.

Adults characteristically present without diarrhea. Illness is milder in young children, where it may manifest as nonspecific fever.

This fever has a low infectious dose (<103), and a long high variable incubation period (1 to 6 weeks)

It is transmitted through person-to-person contact or fecally contaminated food or water.

Fatal complications of typhoid most commonly occur in the second or third week of the illness.