The endemic treponematoses are infectious diseases caused by microorganisms that are closely related to Treponema pallidum, the causative agent of syphilis. This group of entities includes (1) pinta, caused by Treponema carateum; (2) yaws, caused by T. pallidum ssp. pertenue; and (3) bejel, caused by T. pallidum ssp. endemicum. Although all these entities are caused by Treponema species, there are important differences between the endemic treponematoses and syphilis, including a nonvenereal form of transmission, an endemic occurrence in very specific geographic areas, a tendency to affect children rather than sexually active adults, and a less likely risk for congenital transmission to occur. In common with syphilis, every endemic treponematosis goes through an early stage (including primary and secondary), a period of latency, and a late stage. Significant morbidity is associated with progression of the disease, mainly affecting the skin, bone, and cartilage, leading to significant disfigurement, pain, disability, and social isolation, causing more suffering to already disadvantaged populations living in poverty.
From an epidemiologic point of view, global efforts commanded by the World Health Organization (WHO) from 1952 through 1964 resulted in more than 50 million individuals who were treated for endemic treponematosis, with special attention to yaws. The global incidence of endemic treponematoses was reduced significantly, by 95%, from 50 million cases worldwide to a merely 2.5 million cases.1 However, after all the efforts of such campaign, the sustainability of the control program was transferred to local primary care systems in endemic areas. Because of waning and poor commitment in such surveillance programs, there has been a resurgence in the incidence of the endemic treponematoses. A recent study estimates that at least 89 million people are living in yaws-endemic areas.2 The WHO now recognizes all endemic treponematosis as neglected tropical diseases.3 The current WHO goal is to eliminate yaws by 2020; stricter and more sensitive surveillance programs are required to reach such goal. Table 171-1 shows a quick comparison among the three diseases.
TABLE 171-1Clinical Aspect of the Endemic Treponematosis ||Download (.pdf) TABLE 171-1 Clinical Aspect of the Endemic Treponematosis
|FEATURE ||PINTA ||YAWS ||BEJEL |
|Etiology ||Treponema carateum ||Treponema pallidum ssp. pertenue ||Treponema pallidum ssp. endemicum |
|World distribution, main areas ||Probably present focally in Brazilian and Venezuelan green forest ||Papua New Guinea, Solomon Islands, and Ghana ||African Sahel and Saudi Arabia |
|Climate conditions ||Tropical green forest ||Tropical humid ||Hot and dry climate |
|Population affected ||Children and adults ||Mostly children ||Mostly children |
|Transmission ||Close contact ||Close contact ||Close contact and fomites |
|Primary lesion ||Evident, can be multiple, several locations ||One to several, lower extremities ||Rarely evident |
|Predominant lesion ||Vitiligo-like and hyperchromic lesions ||Exudative, papillomatous or papulosquamous lesions ||Moist lesions near mucosal surface or intertriginous areas |
|Nonskin involvement ||None ||Periositis, osteitis ||Periositis, osteitis |