Typhoid infection causes considerable morbidity and mortality worldwide, particularly in settings where lack of clean water and inadequate sanitation facilitate disease spread through faecal-oral transmission. Improved understanding of the pathogenesis, immune control and microbiology of Salmonella Typhi infection can help accelerate the development of improved vaccines and diagnostic tests necessary for disease control. S. Typhi is a human-restricted pathogen; therefore animal models are limited in their relevance to human infection. During the latter half of the 20th century, induced human infection ("challenge") studies with S. Typhi were used effectively to assess quantitatively the human host response to challenge and to measure directly the efficacy of typhoid vaccines in preventing clinical illness. Here, the findings of these historic challenge studies are reviewed, highlighting the pivotal role that challenge studies have had in improving our understanding of the host-pathogen interaction, and illustrating issues relevant to modern typhoid challenge model design.

Original publication

DOI

10.1016/j.jinf.2014.01.006

Type

Journal article

Journal

J Infect

Publication Date

05/2014

Volume

68

Pages

405 - 418

Keywords

Controlled human infection, Enteric infection, Human challenge, Quailes strain, Salmonella Typhi, Typhoid fever, History, 20th Century, Humans, Salmonella typhi, Therapeutic Human Experimentation, Typhoid Fever, Typhoid-Paratyphoid Vaccines