TABLE 15.

Human challenge models for Salmonella Typhi and Salmonella Paratyphi A serovars^a

Organism	Strain	Method of production and administration
Salmonella Typhi	Quailes	Isolated from the gallbladder of a chronic carrier in 1958. A challenge dose of 103 to 104 CFU in bicarbonate buffer solution is ingested.
Salmonella Paratyphi A	NVGH308	Ingestion of 1 × 10³ to 5 × 10³ CFU of the challenge strain in bicarbonate buffer solution.

^aBoth human challenge models have been conducted at the University of Oxford, Oxford, United Kingdom.