Articles on Medical Diseases and Conditions

Entries Tagged ‘Rickettsial Infections’

Cardiolipin Tests

The first practical serologic test for syphilis (STS) was the complement fixation (CF) technique invented by Wassermann. He used extract from a syphilitic liver as the antigen that demonstrated the presence of antitreponemal antibodies. Subsequently it was found that the main ingredient of the substance he used actually had nothing to do with syphilitic infection […]

Immunologic Tests

Immunologic tests for syphilis depend on the fact that the diseases caused by infectious organisms are characterized by development of antibodies toward that organism. These antibodies may be specific or nonspecific (Table 15-1). Nonspecific antibodies may be either of the cross-reacting type (sharing a common antigen with another organism) or of the fortuitous type (provoked […]

Dark-Field Examination

Dark-field is a wet-preparation method for direct visualization of living T. pallidum spirochetes in material from syphilitic lesions. A microscope with a special dark-field condensor is required. This condensor prevents light from passing directly through the slide being viewed into the microscope viewing lenses but instead forces the light to pass to the periphery of […]


Syphilis is caused by the spirochete Treponema pallidum. Clinical syphilis usually is subdivided into primary, secondary, latent, and tertiary (late) stages. The primary stage begins after an average incubation period of 3-6 weeks (range, 1.5-13 weeks) and is manifested by the development of a primary stage shallow ulcer, or chancre, near the site of infection. […]