Yaws

Yaws (synonym: tropical syphilis) is the most widespread highly contagious treponematosis, in which, in addition to the mucocutaneous integuments, the bone system is involved in the pathological process.

The name of the disease comes from the French word framboise ("Framboise") - "raspberry", since in typical cases the rashes externally resemble a raspberry berry. The prevalence of yaws in different countries of Southeast Asia, Africa and Latin America ranges from 2 to 30-40%. These figures relate to manifest forms, while the number of latent cases is about 3 times higher.

Epidemiology of yaws

Yaws have pronounced epidemiological features: it occurs usually in warm and humid climate and extremely rarely in mountainous and desert regions. Infection occurs as a result of direct contact, usually by the household way and very rarely indirectly - through home furnishings. Sexual transmission of infection in comparison with syphilis is negligible (no more than 2%). Ways of infection determine the age composition of the sick: up to 80% of them are children. The transmission of infection contributes to unsatisfactory living conditions (especially the crowded habitat), low overall cultural level of the population, impaired personal hygiene. The entrance gates of infection are damage to the skin and mucous membranes - bruises, scratches, insect bites. Susceptibility to infection is due to age factors: it is insignificant up to 1.5 years, reaches 50% by the age of 5 and is maximal (up to 90%) by 15 years. In adults, yaws are rare, and usually they are infected from sick children. It is allowed to carry the infection mechanically by insects (mites, flies, cockroaches). The possibility of an intrauterine route of transmission is denied (reliable cases of congenital yawing are not given). In experiments, infection of monkeys and rabbits was obtained.

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Causes of yaws

The causative agent is Treponema pertenue, discovered in 1905 by Castellani. By the way, in the same year, the causative agent of syphilis was pale treponema - Treponema pallidum, with which T. Pertenue has a complete morphological property (length, mobility, steepness and number of curls, corkscrew shape). When studying under a microscope in a dark field, both treponemes can not be distinguished from each other. Differences, very insignificant, were revealed only with electron microscopy.

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Symptoms of yaws

The yaws have a staged current. The incubation, primary, secondary and tertiary periods of the disease are distinguished.

The incubation period usually lasts 3-4 weeks. Sometimes at the end of it there are following symptoms of yaws: general weakness, headaches, arthralgia, morning fever. Prodromal phenomena are all the more pronounced, the younger a child is.

The primary period begins with the appearance on the site of the pathogen of the first clinical symptom - a small, usually single, pale pink, itchy papule, in the center of which a small yellow pustule is soon formed. Gradually increasing, the purulent foci is covered with grayish-pink vegetation, occupying its entire surface, which gives it a resemblance to the raspberry berry. The described primary element with the subsequent characteristic dynamics is called pianoma (from "pian" - one of the many synonyms of yaws). Soon, due to the process of neuroticism at the base of the pianoma, it is transformed into a superficial ulcer with a foul-smelling scanty serous-purulent discharge, gradually shrinking into the crust.

Unlike a solid chancre in syphilis, palpation of the base of the pianome reveals a soft consistency. In tissue juice from the ulcer, the causative agent T. Pertenue is easily detected .

Pianoma is most often localized in open areas of the skin - on the face (nose, lips, ear shells), brushes. Often around the primary ulceration appear small secondary sores pianomes - satellites, which, merging with the "maternal ulcer", form larger ulcer surfaces with polycyclic outlines over a vast common crust.

Regional lymph nodes are painful, moderately enlarged, and regional lymphangitis is sometimes clinically discerned in the form of a painful inflammatory tendon.

Pianoma is a very persistent formation and can persist for weeks and months. However, gradually it cicatrizes, the infiltrate dissolves, and in its place remains a portion of whitish atrophy.

Secondary period. Yaws develop a few weeks on the background of a resolving pianome. In this period, generalization of infection is pronounced: numerous itchy eruptions appear on the trunk and extremities in the form of erythematous-squamous spots, papules, vulgar pustules, ulcers, most of which due to the presence of vegetation on the surface become similar to the raspberry berry. These rashes are called Frambazides. They are located in isolation or in groups, the elements of which, during fusion (especially in large folds) form extensive "condylomatous plaques" in the form of arches and rings.

The average lifetime of the Frambizides is about 2-3 months. After their resorption remain areas of superficial whitish atrophy.

In later periods of the secondary period, the appearance of "lupoid scrambids" is possible, which in fact are soft tubercles with subsequent ulceration and the formation of disfiguring scars in the outcome, often leading to elephantiasis and contractures.

Sometimes there are pronounced islet and diffuse keratoderma - hyperkeratoses on the palms and soles with deep, painful cracks, forcing patients to walk from foot to foot, leaning on the outer edges of the feet ("crab walking").

In later terms, the appearance of polyadenite.

In addition to the skin, thromboses can appear on the mucous membranes (in the sky, in the mouth). Sometimes the nails are involved in the process: they thicken, change color, are deformed and even torn away.

The secondary period usually lasts from a few months to two years. The course can be continuous (with the replacement of old rashes with new ones) or wave-like (with alternating seizures and hidden periods of the disease, when the symptoms of yaws for a period of time completely disappear).

Often in 20-30% of patients, the disease passes into its tertiary period (usually in 15-20 years). In the Tertiary period, skin, bones and joints are usually affected. Appear single or multiple soft knots (gum) in size from the walnut to the palm, opening with the formation of languid scarring almost painless ulcers, leading to the formation of scarring contractures. There are synovitis and hydrarthrosis of large joints. Perhaps the development of fibrous gumm ("periarticular knots"). Other organs and systems are not involved in the pathological process.

Among the relatively pathognomonic manifestations of the Tertiary period of the disease, the clinical symptoms of yaws are described: "gundu" and "gangos". Gundu (from the local "big nose") - the defeat of the bones of the face with increasing headaches, bloody-purulent discharge from the nose with the outcome in the tumor-like disfiguring hyperostosis in the region of the nose and cheeks. Gangoza - disfiguring rhinopharyngitis with the development of necrosis of soft tissues and bones in the frontal sinus and pharyngeal area with an outcome in the perforation of the soft and hard palate.

Diagnosis of yaws

Diagnostics of yaws is based on the endemicity of the disease, the characteristic clinical picture, the detection of the pathogen in the discharge vysypnyh elements, positive sero-reactions to syphilis (Wasserman's reaction, etc.). Serological diagnosis of yaws, in particular, of the reaction, in comparison with syphilis, is usually positive in a lower titer. In contrast to syphilis, yaws are endemic, the main affected contingent are children, infection occurs in the family household way (primary affect - pianoma - localized extragenital), rashes give vegetation ("raspberry"), mucous membranes are rarely affected, itching is typical at places of rashes, in late the stages of involvement of internal organs and the nervous system are not observed, there is no congenital transmission of infection.

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Laboratory diagnosis of yaws

Dark-field microscopy and direct RIF method are used to identify the pathogen in skin lesions. Confirmatory serological reactions used for the diagnosis of syphilis, based on a specific ultrasound treponemal antigen (ELISA, RPGA, RIF indirect method), are positive in patients with yaws and thrasher.

Treatment of yaws

Treatment of yaws is analogous to antisyphilitic drugs: penicillin preparations (soluble and durant), reserve antibiotics (tetracycline, erythromycin, sumamed, etc.), topical antiseptics (levomecol, miramistin, aniline dyes).

Prevention of yaws

In connection with the social nature of the infection, its prevention includes improving the sanitary culture of the population, improving living conditions, improving the overall welfare of the population, conducting general surveys in endemic areas, compulsory treatment of yaws for all identified patients and all persons who were in close contact with them. Yaws should be controlled by WHO bodies.