Incubation period of syphilis is

Ans. a (9-90 days). (Ref. Harrison, Medicine, 18th/Ch. 169; Table 170-1)SYPHILIS# L Pallidum enters foetal circulation after 20th week of gestation with disappearance of cytotrophoblast in villi (Kerala-2001).# Basic pathology is obliterative endarteritis, in congenital syphilis.# Placenta becomes bulky and spirochaete can hardly be found in placenta.# Spirochaete can however be detected from maculopapular rash in baby.# Irrespective of the serology, treatment should be repeated in subsequent pregnancies.# Incubation period of syphilis is 9-90 days# In blood transfusion and in congenital syphilis, no chancre occurs.# Dark ground microscopic examination is useful but negative results do not exclude diagnosis of syphilis.# Diagnosis by microscopy is applicable in primary and secondary stages and congenital syphilis.# Wet film prepared with exudates is seen under dark ground microscope.# T. pallidum shows slow movement with slender spiral structure# However, serology remains the best diagnostic test for syphilis.# Serological tests for syphilis are:- Tests for antibodies reacting with cardiolipin antigen (Non-specific reagin test, standard tests for syphilis)* VDRL is std test for syphilis- Tests for antibodies reacting with group specific treponemal antigens.- Tests for specific antibodies to pathologic T. pallidum.Comparison of the Treponemes and Associated DiseasesFeatureVenereal SyphilisYawsEndemic SyphilisPintaOrganismT. pallidum subsp. pallidumT. pallidum subsp. pertenueT. pallidum subsp. endemicumT. carateumModes of transmissionSexual, transplacentalSkin-to-skinHousehold contacts: mouth-to-mouth or via shared drinking/ eating utensilsSkin-to-skinUsual age of acquisitionAdulthood or in uteroEarly childhoodEarly childhoodLate childhoodPrimary lesionCutaneous ulcer (chancre)Papilloma, often ulcerativeRarely seenNonulcerating papule with satellites, pruriticLocationGenital, oral, analExtremitiesOralExtremities, faceSecondary lesionsMucocutaneous lesions; condylomata lataCutaneous papul osquamous lesions; osteoperiostitisFlorid mucocutaneous lesions (mucous patch, split papule, condyloma latum); osteoperiostitisPintides, pigmented, pruriticInfectious relapses25%CommonUnknownNoneLate complicationsGummas, cardiovascular and CNS involve- mentaDestructive gummas of skin, bone, cartilageDestructive gummas of skin, bone, cartilageNondestructive, dyschromic, achromic macules