Tropical syphilis (yaws): causes, symptoms, diagnosis, treatment

Yaws is a tropical infectious disease characterized by high contagiousness, lesions of the skin, mucous membranes, as well as bones and joints. Typical skin papillomatous elements resemble raspberries (French: Framboise).

Causes of Yaws

The causative agent of yaws - Treponema pertenue - is close in morphological and biological properties to the causative agent of venereal syphilis (T. pallidum), but does not cause congenital lesions, since it does not penetrate the placenta. T. pertenue quickly dies under the influence of oxygen, drying and heating; it does not grow on nutrient media, and is visualized in a dark field microscope.

The reservoir of infection is children aged 2 to 15 years.

Epidemiology

Yaws is transmitted by direct non-sexual contact from person to person (with exudate or serum from infectious lesions). Patients in the latent and tertiary periods are practically

The spread of yaws is facilitated by overcrowding and low sanitary and hygienic standards of living.

Course of the disease

The incubation period is 3-4 weeks.

Primary period - up to 0.5 years.

Secondary period - 1.5-2 years.

The secondary period is characterized by a cyclical change of active manifestations and latent (hidden) periods of the disease. Throughout the secondary period (1.5-2 years), 2-3 clinical relapses may be observed, occurring after latent periods. In many patients, the disease ends at this point.

Tertiary period - occurs in 10-30% of untreated patients after 7-25 years against the background of a long latent period that occurs after the completion of the secondary stage of the disease.

Symptoms of Yaws

Primary period - a single papule, soft, itchy, pale pink, with papillomatous growths (raspberry appearance). On the surface of the papule, a shallow ulcer (frambesioma) often forms, which is covered with a crust and heals with a scar. Frambesiomas are usually located in children on open areas of the body, especially on the face (lips, ears, mouth, nose area), hands; in nursing mothers, they are often localized in the mammary glands, and in adult men - on the shins, feet, less often on the genitals.

Secondary yaws - satellite chancres - are possible.

The secondary period is characterized by the appearance of multiple itchy papules on the trunk and limbs - frambesides, which look like raspberries, as well as squamous and erythematous-squamous spots, rarely - papulo-tubercles, vesiculopustules with their ulceration. Often in this period, hyperkeratosis of the palms and soles is detected, which can be limited or diffuse.

The tertiary period is characterized by the formation of gummas, ulcers, scars, gangoses (mutilating nasopharyngitis), osteoperiostitis, saber-shaped shins, hyperostosis of the anterior nasal bone (gundu, gond), periarticular nodules.

Diagnosis of yaws

Diagnosis of yaws is based on:

• results of the epidemiological survey of the outbreak;
• typical clinical picture of the disease;
• detection of the pathogen in the discharge of primary yaws, exudate from the primary lesion, in secondary efflorescences under a dark field microscope;

Treatment of yaws

According to WHO recommendations, prolonged-release penicillin, benzathine benzylpenicillin (BBP), is preferable for treating yaws. In an outpatient setting, one intramuscular injection is given into the upper outer quadrant of the buttock at a dose of 2,400,000 U, which creates a treponemocidal level of the drug for more than 3 weeks. A single administration of BBP provides cure for treponemal diseases and protection against reinfection during this period.

Recommended prophylactic doses of BBP for persons who have been in contact with patients with endemic treponematoses:

• under 10 years of age - 600,000 IU of benzathine benzylpenicillin;
• for persons over 10 years of age - 1,200,000 IU of benzathine benzylpenicillin.

Depending on the prevalence of yaws in endemic areas, appropriate treatment tactics are used. In cases of allergy to penicillin, patients with yaws, endemic syphilis, and pinta are prescribed other antibiotics:

• tetracycline or erythromycin 500 mg orally before meals 4 times a day, the course of treatment is at least 15 days;
• children aged 8-15 years are prescribed half the dose of tetracycline or erythromycin;
• Children under 8 years of age are prescribed only erythromycin in doses corresponding to their body weight.

The drug should be administered in small doses every 4-6 hours for at least 15 days.

It is not recommended to prescribe tetracycline to pregnant women, as it causes kidney complications and affects the formation of the fetal skeleton.

Prevention

• Improving the economic, social and living conditions of the population of endemic areas.
• Timely identification of patients with active forms of yaws and all those who have been in contact with them.
• Identification of patients with latent forms of the disease who are likely to have relapses of contagious frambesides.
• Conducting appropriate treatment for these contingents in order to reduce and eliminate the incidence of this treponematosis;
• Conducting periodic examinations of residents of rural areas where patients with yaws have previously been identified.