Bejel, pinta, and yaws

[Justin Bieber]

Bejel, pinta, and yaws (endemic treponematoses) are chronic, tropical, nonvenereal spirochetal infections spread by body contact. Symptoms of bejel are mucous membrane and cutaneous lesions, followed by bone and skin gummas. Yaws causes periostitis and dermal lesions. Pinta lesions are confined to the dermis. Diagnosis is clinical and epidemiologic. Treatment is with penicillin.
Spirochetes are distinguished by the helical shape of the bacteria. Pathogenic spirochetes include Treponema, Leptospira, and Borrelia. Both Treponema and Leptospira are too thin to be seen using brightfield microscopy but are clearly seen using darkfield or phase microscopy. Borrelia are thicker and can also be stained and seen using brightfield microscopy.
For bejel, pinta, and yaws, the causative agents are

Bejel: Treponema pallidum subsp endemicum
Yaws: T. pallidum subsp pertenue
Pinta: T. carateum

These Treponema species are morphologically and serologically indistinguishable from the agent of syphilis, T. pallidum subsp pallidum. As in syphilis, the typical course is an initial mucocutaneous lesion followed by diffuse secondary lesions, a latent period, and late destructive disease.
Transmission is by close skin contact—sexual or not—primarily between children living in conditions of poor hygiene.
Bejel (endemic syphilis) occurs mainly in hot, dry regions of the eastern Mediterranean and Saharan West Africa. Transmission results from mouth-to-mouth contact or sharing eating and drinking utensils.
Yaws (frambesia) is the most prevalent of the endemic treponematoses and occurs in humid equatorial countries. Transmission requires direct skin contact and is favored by skin trauma.
Pinta, which is more limited in geographical distribution, occurs among the natives of Mexico, Central America, and South America and is not very contagious. Transmission probably requires contact with broken skin.
Unlike T. pallidum, other human treponemal subspecies are not transmitted via blood or transplacentally.