Yaws is mainly found in children who reside in endemic regions. Inoculation occurs when individuals are exposed to infected individuals [6] [7].

The following are the clinical stages:

Primary

The mother yaw, or primary lesion, forms at the contact site. This is usually a minor trauma on the skin, such as a cut, scratch, or bite on the lower extremities or buttocks. Specifically, the lesion appears as a non-tender, pruritic, reddish papule that grows in size and transforms into a papilloma. It contains central hypopigmentation and the healing process takes 3 to 6 months and is followed by the development of scars.

If bones are joints are affected, pain and swelling may ensue. Furthermore, associated symptoms at this stage are fever and lymphadenopathy.

Latency

This phase lasts between 6 to 16 weeks.

Secondary

Disseminated lesions of the skin and bones may form after a latency phase. The daughter yaws are commonly positioned close to the mouth and nose. They grow, ulcerate and produce an exudative fluid containing the organisms. Also, papules, macules and nodules may arise. Overall, secondary lesions may persist for weeks to months and may resolve without treatment. Scarring does not usually occur. This phase may also feature constitutional symptoms.

Complications include thickening of the skin, which manifests as painful hyperkeratotic plaques that form fissures. Consequently, these painful and uncomfortable skin manifestations make it difficult to walk and hence the patient develops a crablike gait referred to as crab yaws.

Bone sequelae include osteoperiostitis and fusiform swelling of the metatarsal and metacarpal joints.

Tertiary

This late stage occurs in 10% of infected patients. It presents with damage to the skin and bones after 5 to 15 years of latency. The nervous system and the eyes may also be affected. Furthermore, this phase is characterized by the formation of well-demarcated subcutaneous nodules, which go on to develop abscesses, necrosis and ulcerations.

Infection of the ulcers is typically followed by further destruction of the skin. If the ulcers coalesce, this results in the production of serpiginous channels that eventually heal with keloid formation. Consequently, these patients suffer from severe deformities and contractures.

Finally, bone complications such as osteomyelitis, hypertrophic periostitis, and others occur.

• Generalized Lymphadenopathy

  Primary stage Early yaws lesions include the following: Papilloma Serpiginous papilloma Ulceropapillomata Squamous macules Maculopapules Nodules Plaques Hyperkeratosis of palms and soles Bone and joint lesions Generalized lymphadenopathy (may occur) The [emedicine.medscape.com]

  Split papules at the labial commissures (angular stomatitis, as in yaws patients) ( Fig. 3C ), nonitchy skin eruptions, generalized lymphadenopathy, and laryngitis are common manifestations ( 54 ). [dx.doi.org]

• Disability

  Eradication would cost US$ 26 (4.2-78) for each year of life lived without disability or disfigurement due to yaws, or US$ 324 (47-936) per disability-adjusted life year (DALY). [ncbi.nlm.nih.gov]

  Yaws is usually not fatal though it does cause disfigurement and disability, which can lead to economic distress for the community as disabled individuals rarely can work to generate needed income, which further exacerbates the impoverishment of the community [reliawire.com]

  Late yaws appears after five years of the initial infection and is characterized by disabling consequences of the nose, bones and palmar/plantar hyperkeratosis. [allcountries.org]

• Weakness

  Many yaws control programs will be executed in areas where the public health infrastructure is weak and constrained by limited human and financial resources. [nejm.org]

  Physical examination showed slurred speech, generalized weakness, and limited lateral eye movement. Reflexes were globally absent, sensation testing was unreliable, and Romberg’s sign was positive. [omicsonline.org]

  These attempts were half-hearted and the goal of eradication remained elusive. 9 At this time, most of the yaws programmes had been integrated into primary health care which were generally too weak to implement the activities of a vertical programme. [who.int]

• Fatigue

  After weeks to years, joints and bones may become painful, fatigue may develop, and new skin lesions may appear. The skin of the palms of the hands and the soles of the feet may become thick and break open. [definitions.net]

  […] a round, hard swelling of the skin, 2 to 5 centimeters in diameter.[4] The center may break open and form an ulcer.[4] This initial skin lesion typically heals after three to six months.[5] After weeks to years, joints and bones may become painful, fatigue [educalingo.com]

  Their bodies were tightly bandaged to enable them to endure the excessive fatigue of their great ride through Central Asia. [britannica.com]

  […] fascitises fashioners fashioning fashionist fastballer fastenings fastidious fastigiate fastigiums fastnesses fatalistic fatalities fatbrained fatherhood fatherings fatherland fatherless fatherlike fathership fathomable fathometer fathomless fatigating fatiguable [findmeaword.net]

  Chronic medical conditions include diabetes, epilepsy, and chronic fatigue syndrome. Disease Illness or sickness often characterized by typical patient problems (symptoms) and physical findings (signs). [healthdictionary.info]

• Collapse

  Other diseases are spreading because people have stopped being vaccinated, as happened with diphtheria after the collapse of the Soviet Union. [encyclopedia.com]

  […] untreated patients will develop tertiary yaws, characterized by subcutaneous gummatous nodules, chronic periostitis that can cause apparent bowing of the tibia (i.e., saber shin) ( Fig. 2F ), and destructive processes leading to saddle nose and perforation/collapse [dx.doi.org]

• Pediatric Disease

  Brand-new chapters and comprehensive revisions throughout ensure that you have the most recent information on diagnosis and treatment of pediatric diseases based on the latest recommendations and methodologies. [books.google.it]

• Cough

  Subsequent epidemics have not been attended by anything like this mortality, but there has, however, been a steady decrease, principally among young children, owing to whooping-cough, tuberculosis and croup. [yourdictionary.com]

• Flatulence

  flatulency flatwashes flauntiest flavanones flavonoids flavorings flavorists flavorless flavorsome flavouring flawlessly fleahopper flechettes fledglings fleeringly fleetingly flehmening flemishing fleshiness fleshliest fleshments fletchings flexitimes [findmeaword.net]

• Saber Shin

  Saber shin due to chronic untreated osteoperiostitis. [slideplayer.com]

  Chronic osteitis of the tibia can lead to saber shins. In about 1% of patients, there is occurrence of bilateral hypertrophic osteitis of the external aspects of the nasal processes of the maxillae with persistent swelling. [emedicine.medscape.com]

  For example, some patients develop destructive ulcerations of the nasopharynx, palate and nose (termed gangosa), painful skeletal deformities, especially in the legs (termed saber shins), and other soft-tissue changes (gummas, inflammatory cell infiltration [medicinenet.com]

• Arthralgia

  The symptoms of yaws are different from syphilis and include: the appearance of papillomatous lesions, arthralgia, malaise, bone and cardiovascular degradation. Of particular note, yaws is easily treatable using a single dosage of antibiotic. [jpoles1.github.io]

  […] antibiotics, hematogenous and lymphatic dissemination of the bacteria may occur and lead to the development of secondary yaws, a condition characterized by contagious, superficial patchy scaling of the skin and plaques of the palms and soles accompanied by arthralgia [nejm.org]

  Site Ano-genital Site Legs, ankles Secondary Incubation Weeks-24 months Incubation Weeks-24 months Clinical presentation Skin rash Lymphadenopathy Mucosal lesions Clinical presentation Arthralgia Malaise Skin lesions Polyosteitis of fingers, feet or long [ncbi.nlm.nih.gov]

  Arthralgias are well-recognized symptoms of secondary-stage yaws and usually affect the knees, ankles, elbows, and wrists. They do not in themselves constitute an indication for a radiological study. [cid.oxfordjournals.org]

  At this stage, regional lymphadenopathy and arthralgia may also occur ( 25, 29 ). [dx.doi.org]

• Skin Ulcer

  METHODS: We performed repeated clinical surveys for active yaws, serologic surveys for latent yaws, and molecular analyses to determine the cause of skin ulcers and identify macrolide-resistant mutations before and 6 and 12 months after mass treatment [ncbi.nlm.nih.gov]

  In both parks skin ulcerations caused by Treponema are common in wild baboons. In about 20 per cent of the wild-caught flies Treponema-DNA was found. [sciencedaily.com]

  Key terms Papule — A raised bump on the skin. Ulcer — A punched-out, irritated pit on the skin. yaws [ yawz ] a highly infectious disease caused by the spirochete Treponema pertenue. [medical-dictionary.thefreedictionary.com]

  Additional benefit would be derived if other common causes of ulcerative skin disease in children could be addressed in parallel. [rstmh.org]

  Ulcers caused by Haemophilus ducreyi is an important cause of skin ulcers (2) (mostly on the legs) which clinically mimic the ulcerative form of yaws complicates clinical diagnosis. [who.int]

• Initial Lesions of Yaws

  Most lesions occur on the limbs. The initial lesion of yaws is teemed with the bacteria. The incubation period is 9–90 days, with an average of 21 days. Without treatment, infection can lead to chronic disfigurement and disability. [who.int]

  Yaws is transmitted through direct (person-to-person) non-sexual contact with the fluid from the lesion of an infected person. Most lesions occur on the limbs. The initial lesion of yaws is teemed with the bacteria. [web.archive.org]

  Disease History, Characteristics, and Transmission The initial lesion of yaws appears where the bacteria enter the skin, and soon a red bump called a papule develops. The papule, measuring 0.8–2 in (2–5 cm) in diameter, is painless but often itchy. [encyclopedia.com]

• Tropical Ulcer

  Yaws simulates the lesions of scabies, impetigo, skin tuberculosis, tinea versicolor, tropical ulcer, leprosy and psoriasis. It may also accompany these diseases. [web.archive.org]

  […] sslid=330&subsublinkid=313 Yaws simulates the lesions of scabies, impetigo, skin tuberculosis, tinea versicolor, tropical ulcer, leprosy and psoriasis. It may also accompany these diseases. [nhp.gov.in]

  Yaws simulates the lesions of scabies, impetigo, skin tuberculosis, tinea versicolor, tropical ulcer, leprosy and psoriasis. The yaws may also coexist with any of these lesions. T here is no natural immunity. [ncdc.gov.in]

  In this region, a diagnosis of yaws can be differentiated from primary lesions of tropical ulcers [ 22, 23 ], hence, usefulness of serological tests to overcome this difficulty with diagnosis. [bmcresnotes.biomedcentral.com]

  Serological prevalence surveys of young children aged COADMINISTRATION WITH OTHER MASS DRUG ADMINISTRATIONS FOR NEGLECTED TROPICAL DISEASES As a future possibility, national yaws programs may explore synergistic collaboration with other neglected tropical [cid.oxfordjournals.org]

• Plantar Hyperkeratosis

  Late yaws appears after five years of the initial infection and is characterized by disabling consequences of the nose, bones and palmar/plantar hyperkeratosis. [allcountries.org]

  Symptoms of Yaws A painless ulcer that has a scab Papillomas A thickening palmar/plantar hyperkeratosis Treatment The treatment for Yaws is not expensive and is a single dose of an antibiotic called: Benzathine Penicillin. [reliawire.com]

  Late yaws appears after five years of the initial infection and is characterized by disfigurement of the nose and bones, and palmar/plantar hyperkeratosis (thickening of the palms of the hand and the soles of the feet). [web.archive.org]

  The operational definition of a case of yaws is "any person who lives in an endemic area and presents with one or more of the following signs: painless ulcer with scab, papilloma, palmar/plantar hyperkeratosis (thickening)" [ 2 ]. [bmcresnotes.biomedcentral.com]

• Eczema

  People with eczema often get skin infections because the breaks in their skin let germs in. If an eczema treatment doesn’t work, or if the rash gets worse, it could be an infection. [webmd.com]

  Contenuti: Skin: basic structure and function -- Cutaneous signs and diagnosis -- Dermatoses resulting from physical factors -- Pruritus and neurocutaneous dermatoses -- Atopic dermatitis, eczema, and noninfectious immunodeficiency disorders -- Erythema [worldcat.org]

  In addition, yaws might be confused with other skin conditions, such as eczema, psoriasis, idiopathic keratoderma calluses, infected bites, excoriated chronic scabies, tungiasis, sarcoidosis, verrucae, and vitamin deficiencies ( 4 ). [jcm.asm.org]

  Furthermore, diagnosis could be difficult in the presence of the dermatophytosis tinea corporis, pellagra, eczema, psoriasis, and leprosy ( 25, 225, 226 ). [dx.doi.org]

• Facial Ulceration

  ulcers, particularly around the nose (gangosa) Pinta lesions are confined to the dermis. [merckmanuals.com]

  Gangosa or rhinopharyngitis mutilans denotes mutilating facial ulceration of the palate and nasopharynx secondary to osteitis. [ncbi.nlm.nih.gov]

• Headache

  Nervous symptoms have never been noticed, if indefinite findings such as headache, backache and pain in the calves may be excluded. Minor changes in the spinal fluid have been found, but this work has only been begun. [jamanetwork.com]

  If there is swelling around the nose, a person with late yaws can have headaches, nasal discharge. The faces of people with late yaws can develop an appearance called goundou. [drugs.com]

  Not only do we have to worry about the regular three headaches such as deforestation, poaching and fatal pathogens like Ebola; but now conservation efforts are impacted because this new pathogen is affecting reproduction and gorilla social group cohesivity [primatology.net]

One component of the patient assessment is the history of the individual which includes any contacts or exposures. Additionally, healthcare workers should consult the WHO clinical pictorial guide to help identify the infection. Further workup includes laboratory studies.

Laboratory tests

Serological tests are commonly used to confirm treponemal infection, however, they do do not differentiate yaws from syphilis. Hence, the clinician should correlate the clinical picture, the epidemiology, and the laboratory findings to arrive at the diagnosis.

The studies include: 1) rapid plasma reagent (RPR), 2) Venereal Disease Research Laboratory (VDRL), 3) fluorescent treponemal antibody absorption (FTA-ABS), 4) T. pallidum immobilization (TPI), and 5) T. pallidum hemagglutination assay (TPHA).

The RPR and VDRL tests are persistently reactive through all the stages. Specifically, they generate positive results as early as 2 to 3 weeks following the presentation of the mother lesion.

There two types of rapid tests that produce the point-of-care (POC) diagnosis [8]. The rapid treponemal tests are widely utilized for the diagnosis of syphilis cases while the rapid dual treponemal and non-treponemal POC test distinguishes the antibodies of yaws from syphilis. It is used in various countries including Ghana, Papua New Guinea, Solomon Islands and Vanuatu to eliminate the disease.

Polymerase chain reaction (PCR) [9] is used to confirm the disease and also to identify resistance to azithromycin.

Other

A biopsy of the lesions can be obtained for histopathologic analysis [10].

The therapy of this infection includes antibiotic treatment. One option is azithromycin, which is prescribed as a single oral dose at 30mg/kg. The maximum is 2 g. Additionally, the drug of choice is benzathine penicillin, which is administered intramuscularly as a single dose of 600, 000 units in children. This dose is doubled in adults. The lesions become non-contagious 24 hours after penicillin treatment. Furthermore, healing occurs within 1 to 2 weeks.

There are alternatives for penicillin-allergic patients such as tetracycline, erythromycin, or doxycycline [11]. If benzathine penicillin is not available, then oral penicillin can be given for a duration of 7 to 10 days [12].

There are treatment guidelines depending on the epidemiologic profile. For example, in communities where more than half of the children are seropositive, then the entire population warrants treatment. When 10% to 50% are seropositive, then all children of ages 15 or under should be treated in addition to the affected individuals and their contacts. Finally, if below 10% of children are seropositive, then treatment is indicated for household members, contacts and infected individuals.

Approximately 10% of untreated patients suffer from disfigurement of the nose and legs in the late stage. This destruction phase results in disabilities that affect their quality of life. Furthermore, some patients will have neurologic and ophthalmologic manifestations.

Untreated patients may have relapses even after 5 to 15 years. During these relapses, the infection targets the skin, bones, and joints.

Note that while the lesions can spontaneously resolve, secondary bacterial infections and scarring are frequently observed.

The organism responsible for yaws is Treponema pallidum subspecies pertenue. This spirochete bacterium is serologically identical to T pallidum, which causes syphilis.

The mode of transmission of yaws is through person-to-person contact, particularly in children who spread the infection through the contact of skin-to-skin or skin- to-mucous membrane.

Note that yaws is not a sexually transmitted infection, nor is it congenital. It is not observed in the urban setting either.

Geographical distribution

Six decades ago, yaws was found in all tropical areas and Africa demonstrated the highest prevalence according to reports by the World Health Organization (WHO) in the 1990s. India announced the eradication of the infection in 2006.

Yaws occurs in tropical forest regions in Africa, Asia, Latin America and the Pacific. Specifically, it is observed in impoverished and overpopulated communities in hot and humid areas.

In 2010, the WHO highlighted that yaws is still common in poor communities and populations. Moreover, it is endemic in Indonesia, Timor-Leste, Papua New Guinea, the Solomon Islands, as well as the African countries of Cameroon, Central Africa Republic, Congo, the Democratic Republic of the Congo, Ghana, Sierra Leone, and others as well.

Patient demographics

Approximately three quarters of infected individuals are younger than 15 years of age and especially in the ages of 6 to 10. In fact, it is believed that there are 34 million people at risk for infection, in which 23 million are less than 15 years of age and the remaining are between 16 and 24 years old.

With regards to gender, there is no preference.

This infection is transmitted when minor skin cuts or abrasions on an unaffected person come into contact with fluid from skin lesions of affected patients. Furthermore, yaws is seen frequently on the extremities.

The incubation period ranges from 9 to 90 days. T. pallidum pertenue enters the subcutaneous lymphatic system and disseminates throughout the body. Yaws occurs in two stages: infectious and non-infectious.

Infectious

This is the early phase, in which the lesion appears as a papilloma that marks the entry site of the organism. This circular, swollen lesion is filled with the spirochetes. Due to hematogenous dissemination, lesions can present everywhere. They typically remain for 3 to 6 months and heal spontaneously. Early yaws may be associated with bone pain and lesions.

Non-infectious

The late stage occurs 5 years after the primary infection. The main features are deformities of the nose and bones, as well as thickening of the palms and soles. Due to the latter, patients experience difficulty when walking.

The key preventative strategies for yaws is health education and implementation of good hygiene.

Note that measures are being undertaken to eradicate the disease, especially through early diagnosis and prompt treatment of active cases. Furthermore, there is targeteted therapy of communities and populations. 

Yaws is the most common infection in the group referred to as endemic treponematoses, which also includes bejel and pinta. The agent responsible for yaws is Treponema pallidum subspecies pertenue, which is transmitted through skin-to-skin contact in individuals typically less than 15 years of age. Furthermore, the disease is frequently observed in poor, unsanitary conditions in tropical areas with hot and humid climates, as well as frequent rainfalls [1].

This infection typically presents as a skin lesion that may disseminate if left untreated. In advanced disease states, yaws affects the skin, bones, and joints; untreated patients may develop physical handicaps and disfigurement [2]. Overall, yaws is a chronic disease that may relapse [3] [4] [5].

Diagnosis is based on a full evaluation including the patient's history and any exposures or contact risks. There are various serologic tests, although certain techniques may not differentiate between yaws and syphilis. Therefore, the diagnosis is determined through assessment of the clinical findings, epidemiology of yaws, and positive laboratory testing.

Therapy consists of either benzathine penicillin or azithromycin. Furthermore, there are guidelines regarding the treatment of the community and population in addition to infected individuals.

The ultimate therapeutic goal is to eradicate yaws, which can be accomplished with early diagnosis and treatment. Other preventative measures include education and practicing good hygiene.

Yaws is a long-term bacterial infection involving the skin, bones, and joints. The bacterium responsible for this disease is called Treponema pallidum pertenue, which is in the same family as the bacteria that causes syphilis. However, yaws is not transmitted sexually. It is transmitted when a scratch, abrasion, or bite comes into contact with a lesion or fluid from a lesion of an affected patient.

This disease primarily infects children under 15 years old in impoverished and overcrowded hot and humid tropical regions in Asia, Africa, Latin America, and the Western Pacific islands.

Approximately 2 to 4 weeks after infection, the patient develops a skin lesion known as "mother yaw" typically on the leg. It may be itchy and, if scratched, the infection may spread to other sites of the body.

The healthcare worker will assess the history and any possible exposures to the disease such as household members, classmates, etc. Also, the healthcare worker will examine and evaluate the lesion. Finally, there are blood tests that will help the medical team to make the diagnosis.

The treatment for this infection is penicillin. Additionally, the clinician will determine who else will need treatment including all exposures (household members, classmates, etc). Early diagnosis and treatment are necessary to finally eliminate this disease.

One of the key ways to prevent this disease is through health education and practicing good hygiene.

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