Animal models are often used to satisfy Koch’s postulates, yet mice and other laboratory animals sometimes react differently than humans to infectious agents. For example, S. enterica serovar Typhi,...

Animal models are often used to satisfy Koch’s postulates, yet mice and other laboratory animals sometimes react differently than humans to infectious agents. For example, S. enterica serovar Typhi, the cause of typhoid fever in humans, a very serious disease, does not cause disease in mice. In other cases, the bacteria localize differently in humans and mice. S. enterica serovar Typhimurium causes a fatal bloodstream infection in mice but causes only diarrhea in most humans. What features of an animal model need to be evaluated before the model is used to satisfy Koch’s postulates?