Microbiology and Epidemiology

The endemic treponematoses-yaws (Treponema pallidum subspecies pertenue), endemic syphilis (T. pallidum subspecies endemicum), and pinta (T. carateum)-are nonvenereal chronic diseases acquired during childhood and caused by organisms closely related to the agent of syphilis, T. pallidum subspecies pallidum.

• Disease is transmitted by direct contact.
• The most recent World Health Organization (WHO) estimate (1995) suggested that there are 460,000 new cases per year and a prevalence of 2.5 million infected persons.
• Disease is limited to people in rural areas of developing nations and recent émigrés from these regions.

Clinical Manifestations

The major clinical distinctions made between venereal syphilis and the nonvenereal treponematoses are the apparent lack of congenital transmission and of CNS involvement in the nonvenereal infections. However, these distinctions may not be entirely accurate.

• Yaws is characterized by the development of one or more primary lesions (“mother yaw”) followed by multiple disseminated skin lesions.
  • At 3-4 weeks after acquisition of the organism, the pt develops a papule that ultimately enlarges to become ulcerated, is associated with regional lymphadenopathy, and heals spontaneously within 6 months.
  • A large proportion of ulcerative lesions in yaws-endemic regions contain Haemophilus ducreyi, either as the sole etiologic agent or in combination with T. pallidum subspecies pertenue.
  • Late gummatous lesions of the skin and long bones affect 10% of untreated persons and are similar to the destructive lesions of leprosy and leishmaniasis.
• Endemic syphilis is initially localized to mucocutaneous and mucosal surfaces. Pts develop an intraoral papule, which is followed by mucous patches on the oral mucosa and mucocutaneous lesions resembling the condylomata lata of secondary syphilis. Destructive gummas, osteitis, and gangosa (destruction of the nose, maxilla, palate, and pharynx) are more common in endemic syphilis than in yaws.
• Pinta is the most benign of the treponemal infections in that it does not cause destructive lesions or involve tissues other than the skin. The disease has three stages that are characterized by marked changes in skin color.

Diagnosis

The diagnosis is based on clinical presentation, dark-field microscopy of scrapings from lesions, and serologic testing (as for venereal syphilis).