TABLE 1.
Presence of treponemes after intradermal challenge
| Challenge strain or isolate | Treponeme positive/totala (% positive)
|
|
|---|---|---|
| Immunized | Control | |
| Nichols | 5/32 (16)b,d,e | 28/32 (88) |
| Clonal Chicago | 11/32 (34)b,c | 24/32 (75) |
| Chicago | 13/32 (41)b,c | 26/32 (81) |
Values are the number of sites with treponemes/total number of sites. The presence of treponemes was detected by dark-field microscopy in aspirates taken from inoculation sites, and 32 inoculation sites were sampled for each group.
Significantly different (P < 0.001) from the value for unimmunized controls by the chi-square test with Bonferroni's correction.
Significantly different (P < 0.001) from the value for immunized rabbits challenged with the Nichols strain by the chi-square test with Bonferroni's correction.
Significantly different (P < 0.001) from the value for immunized rabbits challenged with the clonal Chicago strain by the chi-square test with Bonferroni's correction.
Significantly different (P < 0.001) from the value for immunized rabbits challenged with the Chicago isolate by the chi-square test with Bonferroni's correction.