A contagious infectious disease caused by bacteria, syphilis is the most well-known of the treponematoses. However, there are other treponematoses that exist endemic in some poor regions of the world. What are these diseases? How to recognize them and treat them?

Treponematosis, or treponemosis, is a term designating a set of diseases which are responsible for treponemes, a genus of bacteria belonging to the spirochetes family.

Among the main treponematoses affecting humans, there are 4 different clinical forms: 

Venereal syphilis

Only syphilis venereal, caused by Treponema pallidum, or “pale treponema,” is a sexually transmitted infection. After having almost disappeared in the 1990s in France, it has been in full resurgence since 2000. It includes 3 stages which progressively worsen and lead to a chancre (button) at the point of transmission and skin lesions.

Endemic treponematoses

The other treponematoses are endemic and have in common that they are observed early in childhood and never cause neurological damage and give rise to the same serological reactions as syphilis. We distinguish :

• Endemic non-venereal syphilis or “bejel”, caused by Treponema pallidum endemicum, which occurs in the dry Sahelian regions of Africa;
• Le pian, caused by Treponema pallidum pertenue, now found exceptionally in foci in Central and South America;
• The pint or “mal del pinto” or “caraté”, caused by Treponema pallidum carateum, affecting children of humid tropical or equatorial zones on all continents in Central and South America, characterized by skin lesions.

Depending on the type of treponematosis, the mode of contamination is different. It is a mainly contagious disease, but which is rarely transmitted by accident (bite), through the blood (transfusion), or transplacental (mother to fetus).

Endemic treponematoses 

Their transmission occurs mainly during close, close contact between children and sometimes between children and adults in a context of promiscuity and unstable hygiene:

• The bejel: transmission takes place by oral contact or by sharing dishes;
• Yaws: the most widespread which requires direct contact with the skin and is favored by skin trauma;
• La pinta: Transmission probably requires contact with damaged skin but is not very contagious.

The venereal form of syphilis is believed to have emerged in Europe and the Middle East after a new mutation and a preferred mode of transmission through unprotected adult sex with a person with syphilis during the early stages of the disease. 

• All types of unprotected sex can be contaminating, including oral sex or, sometimes, deep kissing;
• Maternal-to-fetal transmission can also be transmitted during pregnancy.

Syphilis, like endemic treponematoses, evolves in the same way. An initial lesion followed by diffuse secondary lesions, then a waiting period and finally a late destructive disease.

Endemic treponematoses

• The bejel: mucosal lesions and skin lesions, followed by bone and skin lesions; 
• Yaws causes periostitis and skin lesions;
• The pinta lesions are confined to the dermis. 

Syphilis

After infection, the person will notice one or more red pimples on their genitals or at the back of their throat. This pimple changes to a painless ulcer that can persist for 1 to 2 months. A few weeks after the onset of the ulcer, a flu-like syndrome is felt. Pimples or redness may appear on the palms of the hands and the soles of the feet. Sometimes disorders such as meningitis, paralysis of part of the face, are present. In some cases, the eyes are affected.

Two years after contamination, the symptoms disappear. This phase can last for several decades.

It is a mild disease if it is treated in time, serious if it is ignored or neglected.

Syphilis, like endemic treponematoses, can be treated with a single injection of an antibiotic from the penicillin family. 

The WHO recommends the prescription of a single injection of benzathine benzylpenicillin (2,4 MU), intramuscularly (IM), or in case of allergy to this antibiotic, doxycycline, of the cyclin family. When this substance cannot be used, other antibiotic options exist. 

The effectiveness of antibiotic treatment can be assessed by regular blood tests.