What is Yaws?

Yaws – anthroponotic non-venereal treponematosis with a contact mechanism of transmission of the pathogen. It is characterized by lesions of the skin, mucous membranes, bones and joints.

The term “frambesia” has a French origin (frambois – raspberry) and was proposed in 1768 by French dermatologist Boissierde Sauvage. The first descriptions of the clinical elements were published by Quiedo (1525), Bonitus (1642) and Piso (1648). After the end of the Second World War, yaws was the most common disease in tropical countries. According to the WHO, there are still more than 50 million patients with yaws or its varieties in equatorial Africa alone, because treponematosis of the yaw-like type — pint, bejel varies in its clinical manifestations and epidemiological peculiarities depending on natural, environmental conditions. For many tropical countries, frambesia, pint and bejel are not only medical, but also a social problem, because they are accompanied by severe systemic disorders with disability and end up with disability.

Causes of Yaws

The causative agent of the disease Treponema pertenue Castellani, (Treponema Variabilis), discovered in 1905, is a spiral treponema with a length of 8 to 20 microns and a diameter of 0.2 to 0.4 microns, very similar to the causative agent of syphilis. Filed N. M. and V. Ovchinnikov Delektorskaya (1974), Treponema pertenue Castellani differs only by the presence of Treponema pallidum bilayer membrane complex, but a monolayer cytoplasmic membrane and cysts with monolayer envelope (pale treponema has a three-layer membrane, the cytoplasmic membrane bilayer and cysts with a three-layer sheath).

The absence of a multi-layered cytoplasmic membrane in Treponema pertenue and in its cysts contributes to a more effective effect of antibiotics on it. The antigenic properties of Treponema pertenue and Treponema pallidum are very similar, especially in the concentration of lipid, immunofluorescent and immobilizing antibodies. Therefore, the reaction of Wasserman, RIF and RIBT during frambesia is positive, although the titer of lipid antibodies, as a rule, with yaws is somewhat lower than with syphilis. The antigenic community of both treponemas causes cross-immunity between syphilis and yaws.

Pathogenesis during Yaws

Great importance in the occurrence of the disease belongs to natural factors. Frambesia is especially common in countries with rich tropical vegetation, high annual temperatures of air and soil, and humidity due to the abundance of annual precipitation. Infection often occurs through contact with the soil. Entrance gates are microtrauma of the skin and mucous membranes. Infection is possible either directly, through direct contact with patients, or indirectly, through contact with household items, production tools, tools contaminated with purulent discharge. It is believed that in the spread of infection a significant role belongs to insects, which are the mechanical carriers of infectious agents. Susceptibility to Tr. pertenue Castellani is different. Due to passive immunity, the incidence among children under 2 years of age is practically absent. The greatest degree of damage to children is noted at the age of 3 to 16 years, as in these age groups passive immunity is gradually depleted, and the active production of protective antibodies is formed slowly. By puberty, the degree of active immunity increases, and therefore the number of diseases by the age of 16-18-20 is significantly reduced. Thus, children are the main reservoir of infection, and adults are more likely to become infected from sick children. Along with climatic conditions, a low cultural level, lack of sanitary and hygienic conditions, overcrowding, and malnutrition contribute to morbidity.

Analyzing epidemiological data, a number of domestic and foreign authors (Kassirsky, I. A., Plotnikov, I. N., 1964; Cockburn, T., 1961; Schofield, S., 1979, and others) tend to attribute frambesia to non-venereal treponematosis, since sexual contacts in the total amount of epidemiological factors have an insignificant share. Transplacental transmission of infection is not marked. Experimental yaws obtained by infecting rabbits, chimpanzees, orangutans and hamsters.

Symptoms of Yaws

According to the international nomenclature of clinical manifestations of yaws, proposed in 1955 by Hackett, who led the WHO expert group, during the course of the disease there are early and late stages. The early and secondary periods are related to the early phase of frambesia, and the tertiary period of the disease to the late stage. Early manifestations of frambesia are characterized by a multiplicity and dissemination of lesions, contagiousness, and damage not only to the skin, but also to the mucous membranes, bones and joints. Distinctive features of clinical manifestations, along with an abundance of efflorescences, their superficial location are benignity, the absence of necrotic evolutionary transformations and the tendency to spontaneous resolution. The late stage, on the contrary, is characterized by limiting, localized, deep inflammatory nodes that undergo disintegration, destruction involving not only the skin, but also the subcutaneous base, bones, tendons, and joints.

The early stage of frambesia includes an incubation period, primary affect and secondary disseminated rashes. The incubation period varies from 3-6 weeks. up to 4 months In contrast to the incubation period for syphilis, which proceeds unnoticed, without prodroma, with yaws, pronounced prodromal phenomena are observed: chills, headaches, feverish state, pain in bones, joints, and gastrointestinal disorders. The prodroma in children is especially difficult.

Primary affect, or frambese chancre (frambesome, pianoma), is formed at the site of Tr introduction. pertenue Castellani in the form of a flat, doughy nodule or pustule with papillomatous growths covered with caseous yellowish-green discharge or abundant pus shrinking into massive crusts. Often, at the base of the element, ulceration occurs with the formation of a crater-shaped ulcer, the bottom of which is covered with granulations with multiple papillomatous outgrowths, which makes it resemble a cancer ulcer. The base of the ulcer, granulation and papillomatous growths are distinguished by juiciness, softness of the infiltrate, bleeding. The discharge contains a large number of pathogens that are easily detected by microscopy in the dark field of view.

Under the influence of the maceration of the epithelium purulent discharge and the introduction of the pathogen into the new entrance gate, daughter, so-called chancry satellites are formed around the primary form at different stages of development. Their subsequent expansion into the periphery and along the periphery with ulceration of the tissue and hyperplasia of the dermal papillae is completed by merging with the formation of large conglomerates of infiltrative-ulcerative character with papillomatous outgrowths and caseous discharge. Frambesomes are accompanied by lymphangitis and lymphadenitis – inflammatory, painful, often complicated by secondary infection. The healing of the primary affect occurs in different ways and depending on the depth of the lesion. Superficial frambezomas are resolved with the formation of hypopigmented or hyperpigmented spots with slight desquamation. Deep knotty-ulcerative primary affects leave scars. Most often, frambesomas are localized on the lower limbs, hands, mouth, red border of the lips, genitals.

After 3-6 weeks from the moment of occurrence of the primary focus, the first wave of hematogenically generalized early lesions on the skin and mucous membranes and infection of bones and joints begin. After 3-6 months these manifestations spontaneously disappear. There comes a latent period, which is then replaced by a relapse of early frambese lesions. Relapse may be several, and, the longer the infection, the latent period is longer, and the rash less abundant. Approximately 5 years later, a late stage begins with knotty-ulcerative elements, which, like early frambesia lesions, can undergo spontaneous resolution after several months or years, giving way to the latent phase of the disease.

Secondary lesions on the skin and mucous membranes are called frambesida. Early frambesides are represented by polymorphic morphological elements: erythemato-desquamative, papular-papillomatous, lichenoid, hyperkeratotic, erosive, and erosive-ulcerative. They are localized on any part of the skin and, as a rule, multiple, disseminated. Spotted frambesides are characterized by stagnant brown color, abundant small-plate peeling and a tendency to merge. They exist for a short time, are depigmented in the center, leaving a hyperpigmented border in a circle, then disappear without a trace after 2-4 weeks. Spotted frambesides are often combined with early papular and papillomatous forms. Papular elements are dense, brownish-red, scaly and cause a grater on palpation. The size of papules varies from miliary to nummular. Peaked papules or papillomatous growths are often observed. Being localized in large folds and in the genital area, they hypertrophy and erode, resembling widespread warts in patients with syphilis. Especially often spotty-squamous and papular rashes are located on the palms and soles, where pronounced hyperkeratosis, cracks, painful erosions, crater-like depressions with a dry bottom and undermined edges are formed. On the surface of cracks and erosion, papillomatous outgrowths are formed with purulent discharge, containing a large number of pathogens. Hyperkeratotic layers, interspersed with painful cracks and erosions on the soles, impede movement, which changes the patient’s gait, due to which this form of the disease is called “crab yaws” (“crab yaws”).

The lesion of bones and joints in the early stage of frambesia is manifested by a painful swelling, swelling of the soft tissues over the affected bone sites. The phenomena of periostitis, osteitis or osteoperiostitis of the long tubular bones (tibial, radial, etc.) are short-lived, not accompanied by ulceration and necrosis, and after 2-3 weeks. disappear without a trace. Due to the hypertrophic osteoperiosteum of the tibial and radial bones, saber drumsticks and an arcuate curvature of the forearm are often formed. Later, in the later period of the early stage of yaws, hydrartosis, tendovaginitis, and synovitis occur. In children, phalangeal osteoperiosteitis of the hands (polydactylitis) with edema and sharp soreness that impede movements are often observed. In the same period a peculiar lesion of the bones of the nose, the Gundu, is formed. As a result of osteoperiosteitis of the bones of the nose and upper jaw, followed by edematous infiltration of the skin, dense rounded tumor-like projections form on both sides of the nose, on the cheeks, on the forehead. Tumor formations deform the bones of the nose, hard palate, grow into the orbit, make it difficult to nasal breathing. The skin over the tumor is not soldered to the underlying tissues, not ulcerated, painless. The disease is accompanied by intense headache and sumicular-purulent discharge from the nose.

Late frambesid skin, represented by deep gummy tumor nodes and diffuse infiltration, are subjected to expression, destruction, scarring. Gummy-ulcerative foci are characterized by testoval density, bluish-brown or brown-red color, severe pain and red papillomatous granulations. Ulcers with sharp, crater-like edges are accompanied by pain.

Their bottom is uneven with scant discharge among papillomatous granulations. The ulcers scar with the formation of coarse keloid protrusions and contractures.

The defeat of the bones in the late stage of frambesia is the development of gummy periostitis, osteitis and osteoperiostitis with necrosis and destruction of bone tissue, spontaneous fractures, false joints and disability of patients. Often affects the bones of the legs, forearms, hands. However, often the process involves ribs, sternum. The lesion of the joints occurs in the form of gummous arthritis with damage to the intra-articular part of the epiphysis, cartilage, articular capsule and the formation of hydrartosis, synovitis, bursitis with deformities, ankylosis. When the gummous process spreads to the periarticular tissue, deeply penetrating, nonhealing ulcers occur, leading to disability of patients. This phase of frambesia is characterized by mutilating rhinopharyngitis – gangosa (gangosa), which is a gummy lesion of nasopharyngeal structures with partial or complete destruction of the cartilage and bones of the nose, hard and soft palate, and adjacent soft tissues of the face. Gangoses are accompanied by pain in the frontal region and succinic nasal secretions containing inclusions of destroyed bone parts. Gummy infiltration extends to the wings of the nose, cheeks, upper lip, where deforming infiltrates and ulcerations are visible. The process ends with scarring and disfiguring destructive destruction of the soft and hard palate, nose, frontal bone with the formation of cerebral hernia. Fibrous periarticular nodularities characterized by pronounced density and painlessness are also characteristic of the late stage of frambesia.

Without treatment, approximately 10% of people suffering from yaws after 5 years develop complications leading to disfigurement and disability, as the disease can cause significant destruction of the skin and bones. It can also cause deformities of the legs, nose, palate and upper jaw.

Diagnosis of Yaws

The diagnosis is based on the endemic nature of the spread of the disease, detection of the pathogen in the discharge of early and late manifestations of frambesia, the presence of characteristic papillomatous growths resembling raspberries, positive results of serological reactions with lipid antigens and successful results of treatment with penicillin, tetracycline.

Treatment of Yaws

In the early stage of frambesia, penicillin preparations are prescribed (bitsillina, PAM, extensillin) in the amount of 1,200,000-2,400,000 IU per 1-2 injections. In later forms, 4,800,000 IU are administered as 2-4 injections at intervals of 5-10 days. Already after 24-28 hours, the pathogen of the disease disappears, but resolution of manifestations occurs after 1-1.5 months. Late forms are also subject to regression, but not earlier than 1.5-3 months. Tetracyclines, chloramphenicol, cephalosporin, erythromycin 1 g per day for 14 days are also used. For preventive treatment, in case of contact with patients, 1 injection of durant penicillin is given (for adults in the amount of 600,000 IU, for children under 15 years old – 300,000 IU).

Yaws Prevention

Prevention of yaws is carried out in two directions. The first is the routine identification of patients with active and latent forms in endemic areas, and preventive penicillin therapy. So, after the mass prophylactic penicillin therapy in Haiti in 1962, the incidence decreased 40 times. Many agricultural laborers who were disabled returned to work. The second direction in the prevention of yaws is to increase sanitation and hygiene literacy, sanitary culture. Great importance is attached to the prevention and treatment of minor injuries in children and adults in domestic and industrial conditions.