Background: Salmonella enterica subsp. enterica serovar Typhi (antigenic formula 9,12[Vi]:d:-) is a serovar of the O:9 (D1) serogroup. S. Typhi causes typhoid fever, a life-threatening disease characterized by sustained fever as high as 103° to 104° F (39° to 40° C). In developed countries, this serovar is considered rare; however, in developing countries in Africa, Asia, and Latin America is among the top ten Salmonella serovars causing disease in humans, where it kills approx. 600.000 people annually. A number of projects have sequenced the genome of S. Typhi strains; these studies have concluded that S. Typhi is a highly clonal serovar that emerged approx. 30,000-50,000 years ago. Horizontal gene transfer had played an important role in the evolution S. Typhi, including the acquisition of plasmids encoding multiple antibiotic resistant genes.
Animal reservoir: S. Typhi is a human-restricted serovar.
Geographical distribution: S. Typhi is widely distributed; however, the prevalence of this serovar varies considerable. In developed countries (U.S., Canada, Europe), S. Typhi isolations correspond to less than 1% of all Salmonella serovars isolated from humans. In developing countries, isolations correspond to approx. 30% in some countries in Latin America and Asia.
Outbreaks: Salmonella Typhi has caused multiple outbreaks and sporadic cases, including outbreaks in the U.S. and Europe. In developing countries with endemic presence of typhoidal Salmonella, outbreaks are mostly undetected.
Year |
Location |
Associated source |
Number of cases |
2010 |
US-multistate |
Frozen mamey fruit pulp |
9 |
2002 |
Nepal |
Drinking water |
5963 |
2000 |
US-New York |
Food handler |
7 |
1999 |
US-Florida |
Frozen mamey fruit pulp (imported) |
16 |
1998 |
France |
Chicken rice |
27 |
1997 |
France |
Pork, food handler |
26 |
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