eMedicine Specialties > Infectious Diseases > Bacterial Infections

Treponematosis (Endemic Syphilis)

Author: Steven Fine, MD, PhD, Assistant Professor, Department of Internal Medicine, Division of Infectious Diseases, University of Rochester School of Medicine
Coauthor(s): Lynn S Fine, PhD, MPH, Manager of Clinical Microbiology Laboratory, ACM Medical Laboratories; Adjunct Professor, Department of Biology, St John Fisher College and Nazareth College
Contributor Information and Disclosures

Updated: Apr 30, 2009

Introduction

Background

Treponematosis, also known as treponemiasis, traditionally refers to the group of nonvenereal diseases (including endemic syphilis [nonvenereal syphilis]) caused by Treponema species that are morphologically and serologically identical to each other and to Treponema pallidum subspecies pallidum, the cause of syphilis. They differ only in their clinical manifestations. All Treponema species typically associated with nonvenereal disease are transmitted among children living in tropical and subtropical climates, chiefly by direct contact. In humans, the pathogenic treponemes include T pallidum pallidum, Treponema pertenue (yaws), Treponema endemicum (bejel or endemic syphilis), and Treponema carateum (pinta).

Pathophysiology

Treponemes usually invade traumatized cutaneous or mucosal surfaces that come in contact with a draining open sore of the index case. A primary cutaneous lesion appears at the site of inoculation following an incubation period of a few weeks. Treponema may be spread from this site either topically (by scratching) or hematogenously. These lesions often heal. Treponematosis can remain latent or it may recur.

The secondary stage of any of these diseases follows the dissemination of the treponemes. It may begin while the primary lesion is still present or after a variable latent period. It may also resolve spontaneously, recur, or persist. The long-term effects of these infections include multiple cutaneous lesions and destruction of bones or cartilage.

Frequency

United States

Although treponematosis does not occur in the United States, imported cases have been documented.

International

In 1997, the World Health Organization (WHO) estimated that 460,000 new cases of endemic treponematosis occurred worldwide. Currently, more than 2.5 million people may be infected.

Endemic syphilis (bejel) (T pallidum endemicum) is typically spread among children, most commonly in the Middle East and the southern regions of the Sahara Desert. In Europe, cases have been diagnosed in children who have moved from endemic areas. In one study, 12% of children younger than 5 years in Niger were seropositive.¹ High rates of seropositivity are also observed in Mali, Burkina Faso, and Senegal. Pinta (T carateum), which occurs in the Caribbean and in Central and South America, is more common in young adults.

Yaws (T pallidum pertenue) occurs mainly in equatorial regions and can be found in South America, Central America, the Caribbean, Africa, and Southeast Asia. It is associated with high humidity and rainfall. Fifty years ago, the WHO recognized that endemic treponematoses—yaws in particular—were a major cause of disfigurement and disability and a significant economic burden in poor countries.

In Haiti and the Dominican Republic, a pilot project was initiated to eradicate the disease with mass applications of penicillin. This project was so successful that it was extended to 46 other countries. Overall, the incidence of yaws was reduced to isolated foci of endemicity. As public health priorities changed and support for the eradication programs lapsed, the disease saw a resurgence in the 1970s and 1980s. The introduction of mass treatment has been necessary in some areas.

Mortality/Morbidity

Untreated treponematosis may cause disfiguring cutaneous lesions and deformities of the bone and cartilage, potentially leading to significant disfigurement, pain, and disability. Treponematoses can extract a significant economic toll on already disadvantaged populations. Fortunately, with penicillin therapy, cure rates of 95%-97% are possible.

Race

Treponematosis has no reported racial predilection in terms of frequency or severity.

Sex

Treponematosis has no reported sexual predilection in terms of frequency or severity.

Age

Although individuals of any age can acquire treponematosis, endemic syphilis and yaws are more common in children younger than 10 years, whereas pinta is more common in young adults. Yaws most often infects children and peaks in those aged 2-10 years. Of new cases, 75% arise in children younger than 15 years. Congenital infections with the endemic treponemes are unusual because most primary infections occur in children. Primary treponematosis during pregnancy is rare.

Clinical

History

• Patients with treponematosis may present with a characteristic rash or lesions that either do not heal or that continue to spread.
• Patients often have a history of living in or extended travel to endemic areas.
• Patients in later stages may present with various skin, bone, and joint manifestations.

Physical

• Endemic syphilis (bejel) (T pallidum endemicum)
  • The primary lesions are painless, white, mucinous ulcers within the oral cavity, where they may be overlooked.
  • Secondary lesions may be in the mouth or widely disseminated. The secondary lesions may be papules, macules, or various other rashes.
  • The organism may infect the periosteal space, which leads to bone deformities.
  • Late in the disease course, a condition known as gangosa (destruction of nasopharyngeal cartilage) may occur.
  • Ocular manifestations include uveitis, optic atrophy, and chorioretinitis.²
• Pinta (T carateum)
  • Pinta, which occurs in the Caribbean and Central and South America, is more common in young adults. It is favored by an arid rather than humid climate. Over the past 2 decades, the incidence of pinta has been reduced to only several hundred reported cases annually.
  • The primary lesions appear 1-3 weeks after inoculation as slowly enlarging copper-colored papules, which may become hyperkeratotic and blue. Smaller satellite lesions may be observed and may coalesce with the larger ones. The lymph draining this area may be swollen. Lesions may persist for years and may heal, leaving hypopigmentation.
  • Secondary lesions may develop within 3-12 months as small papules, which are often located at the site of primary lesions. The lesions may be numerous and are called pintids. They are initially red but can become pigmented and appear blue over time. Lesions may later become depigmented to varying degrees, leading to a mottled appearance. Later manifestations are limited to cutaneous involvement. The deeper tissues or viscera are not involved.
• Yaws (T pallidum pertenue)
  • The primary lesion occurs 2 weeks to 6 months after inoculation. It begins as a papule that typically becomes a large papilloma. This may persist for several months and then may resolve spontaneously, often with scarring. During this stage, the treponeme may disseminate via the bloodstream or the lymphatics or topically through excoriation by the individual.
  • Secondary disease can involve multiple cutaneous lesions, including macules, papules, nodules, hyperkeratoses, and ulcerations. Lymphadenitis with swollen and tender lymph nodes may occur proximal to lesions. Periosteal infection and destruction of cartilage occur later in the course of the disease.
    
    

    

    Nigerian boy with ulcerative skin lesions characteristic of yaws. Courtesy of the CDC/Dr. Lyle Conrad.

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    Nigerian boy with ulcerative skin lesions characteristic of yaws. Courtesy of the CDC/Dr. Lyle Conrad.

  • The initial lesions characteristically resolve spontaneously by 6 months but then recur after a latent period. Relapses often occur for up to 5 years, after which they diminish in severity and frequency.
  • Approximately 10% of patients with untreated yaws develop late disease, including periosteal lesions that damage bone.
  • Deformities are also observed, including saber shins caused by chronic periosteal infection of the tibia and gangosa, as well as destruction of the cartilage in the nose.
  • Other late-stage manifestations include hyperkeratoses of the palms and soles, which may fissure, predisposing to painful secondary bacterial infections, and gummas of the skull, sternum tibia, and other bones.

Causes

Direct contact with lesions, or in the case of endemic syphilis, fomites, spreads treponematoses.

• Endemic syphilis (bejel) (T pallidum endemicum)
  • The organism can be indirectly transmitted onto objects and by direct contact with lesions.
  • Much of the transmission is thought to be from mouth-to-mouth contact or from shared eating utensils or drinking cups.
• Yaws is transmitted by direct exposure to skin lesions that shed the treponemes.

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