LSH hamster model of syphilitic infection.

The inbred LSH/Se LAK strain of hamster can be infected with Treponema pallidum Bosnia A, the causative agent of endemic syphilis. When infected, this strain consistently produced extensive chronic skin lesions that persisted for 6 to 9 months, even in the presence of peak antitreponemal antibody titers. The lymph nodes increased in weight and contained measurable numbers of treponemes. This infection also gave the hamster cross-immunity to T. pallidum Nichols and Treponema pertenue, the causative agents of venereal syphilis and frambesia, respectively. LSH hamsters are thus an excellent model to study the immune response mechanisms to syphilitic infection.