TABLE 1

Incidence of diarrhea and clinical symptoms after oral challenge of Aotus nancymaae with escalating doses of S. flexneri 2a strain 2457T and homologous rechallengea

GroupTreatment (dose [CFU])Primary challengeHomologous rechallenge
No. of animalsIncidence (%) of diarrheabIncidence (%) of clinical symptomscP valuedNo. of animalsIncidence (%) of diarrheaIncidence (%) of clinical symptomsP value
1S. flexneri 2a 2457T (5 × 109)8e25500.5588e25380.145
2S. flexneri 2a 2457T (5 × 1010)956560.0577e,f43711.000
3S. flexneri 2a 2457T (5 × 1011)91001000.00018f38500.321
4PBS101010105080
  • a The groups of Aotus nancymaae monkeys were challenged with S. flexneri 2a strain 2457T, treated with 1 × 1011 CFU of S. flexneri 2a 2457T, and then rechallenged with a homologous strain.

  • b Diarrhea was defined as at least one loose-watery stool on at least two consecutive days during the observation period (10 days).

  • c Clinical symptoms of Shigella-induced gastroenteritis were defined as evidence of Shigella colonization (PCR or isolation) and either (i) an episode of diarrhea, (ii) blood in the stool (occult, gross, or melena) for two consecutive days, or (iii) death.

  • d The P values were calculated by Fisher's exact test compared to control group inoculated with PBS.

  • e One animal excluded from data analysis due to diarrhea for 2 days prior to challenge.

  • f One animal euthanized after the primary challenge.