Some strains produce H2s gas and necrotizing ulcerative gingivitis
Antibody Responses Elicited against the Treponema pallidum Repeat Proteins Differ during Infection with
Different Isolates of Treponema pallidum subsp. pallidum

Syphilis is a chronic disease caused by Treponema pallidum subsp. pallidum. During the early stages of infection, the
host mounts a vigorous immune response that is able to clear the majority of the treponemes from early lesions but is
unable to completely eradicate the infection. Phagocytosis of opsonized treponemes by macrophages is the primary
mechanism by which the host immune system clears treponemes from early lesions (1, 13, 15). While T. pallidum has
been shown to be susceptible to bactericidal and opsonic antibodies (2-5, 15), the inability to culture the organism,
combined with the fragile nature of its outer membrane, have made the positive identification of outer surface
molecules that may be antibody targets difficult and often inconclusive (8).

Infection and Immunity, October 2003, p. 6054-6057, Vol. 71, No. 10

Pathophysiology: Three genera of spirochetes cause human infection: (1) Treponema, which causes syphilis,
yaws, and pinta; (2) Borrelia, which causes Lyme disease and relapsing fever; and (3) Leptospira, which causes

The organism can cross the placenta and infect the unborn child.

Transmission occurs by penetration of the spirochetes through mucosal membranes and abrasions on epithelial
surfaces. Incubation time from exposure to development of primary lesions averages 3 weeks but can range from
10-90 days. Lesions develop at the primary site of inoculation. Pathologically, the primary lesion of syphilis is a focal
endarteritis and periarteritis. Rabbit studies show that spirochetes can be found in the lymphatic system as early as
30 minutes after primary inoculation, suggesting that syphilis is a systemic disease from the outset.