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PubMed2003

Efficacy of a targeted, oral penicillin-based yaws control program among children living in rural South America.

Yaws is endemic in rural Guyana. An observational study was conducted to determine the efficacy of oral penicillin V therapy in treating skin lesions of yaws in children. In 1999, inhabitants of 7 rural villages near Bartica, Guyana, were screened for skin lesions of yaws. Cases were confirmed by serological testing. A control program was implemented in 2000: children < or =14 years old were screened, and those with active lesions were treated with oral penicillin V for 7-10 days. In 2001, children were rescreened and active cases were treated. Prevalence of yaws skin lesions fell from 5.1% (52 of 1020 children screened in 2000) to 1.6% (8 of 516 in 2001), a 71% drop. Sixteen (94%) of 17 children treated in 2000 and reassessed in 2001 had complete resolution of lesions. A targeted, oral penicillin-based treatment regimen can successfully treat dermatologic yaws in individual children and can decrease the prevalence of skin yaws in a community in which it is endemic. This information may aid in the implementation of additional control efforts.

Administration, Oral↗

PubMedDate not supplied

Surveillance and control of resurgent yaws in the African region.

Yaws, once one of the most common infections in Africa, was expected to be eliminated in some countries and controlled in others after the mass treatment campaigns sponsored by the World Health Organization and the United Nations Children's Fund during the 1950s and 1960s and the implementation of improvements in education, sanitation, and other health-promoting activities. However, the curtailment of yaws control activity allowed the reservoir of untreated yaws to grow unchecked, and the number of reported cases of active yaws has increased in certain parts of Africa, especially in West Africa. In the Central African Republic, the prevalence of yaws is notably high among the Pygmies. Renewed programs for yaws control are under consideration. Mass campaigns are still necessary in some developing countries for the control of certain diseases but should be complementary to the development of general health services and should not be limited to the administrative borders of a given country.

Africa↗

PubMedDate not supplied

Feasibility of eradicating yaws.

The elimination of yaws from large geographic areas provides evidence that global elimination of person-to-person yaws transmission is feasible. The failure to reach that goal to date is the result of managerial rather than technical deficiencies. If the eradication of yaws can be accomplished, it should be done to reduce the suffering that is associated with the disease. In addition, a positive benefit-cost ratio is likely to be realized within a period of decades, and in areas endemic for yaws, its elimination could well provide a basis for the development of a strong system of primary health care. The decision to eliminate yaws must be made deliberately by the World Health Assembly with full knowledge of the implication of not making such a decision. A positive decision would result in enriched lives for countless potential victims of yaws and save the world money in the long term.

Humans↗

PubMed1956

An analysis of the results of the treatment of yaws with a single injection of procaine penicillin with 2% aluminium monostearate.

An extensive yaws eradication campaign has been in operation in Haiti since 1950; this paper deals with material from a special clinic set up at Bainet to evaluate the results of single injections of procaine penicillin with 2% aluminium monostearate (PAM) in various dosages. Treatment results in 862 patients with darkfield-positive secondary yaws and given 600 000 units of PAM are analysed according to age and sex; according to whether the patients lapsed from observation for relatively long periods during the first post-treatment year; and, since an unsatisfactory PAM preparation was used early in the campaign, according to the preparation received. Analyses are also made of results in patients with primary yaws receiving 600 000 units of PAM and in patients with secondary yaws receiving 300 000 units or 150 000 units.It is concluded that a schedule of 600 000 units in a single injection is the treatment method of choice for mass campaigns against yaws, being highly satisfactory in both the primary and secondary stages of disease, provided the PAM preparation conforms to certain minimum standards. The authors also point out that the criteria for the re-treatment of yaws patients after penicillin therapy must be different from those ordinarily adopted with syphilis patients.

Haiti↗

PubMed1960

Some epidemiological aspects of yaws eradication.

Much has been learnt of the epidemiology of yaws during eradication campaigns in populations in which the prevalence of active yaws was high, but not all has been published. The recognition of the importance of latent cases in the maintenance of yaws has contributed to the effectiveness of these campaigns. Yaws eradication activities are extending into populations where at present active yaws is often not high. Planning of effective and economical eradication measures, especially in such populations, needs as complete a picture of the disease as possible, from its transmission and the factors that favour this until the death of the infected person, before or after cure of the infection either after chemotherapy or spontaneously.By revealing the many gaps that still remain in our knowledge of yaws, this summary may encourage those who have gathered valuable material during field work to study and prepare it for publication.

Health Services Needs and Demand↗

PubMed1986

Papua New Guinea. Yaws problems assessed.

The present status of yaws in Papua New Guinea cannot be determined because of the lack of data. Because yaws was deemed under control as a result of the nationwide total mass treatment campaign in the late 1950s and limited regional effort in the late 1970s, the health department lost interest in yaws and pursued other diseases. Individual reports from certain areas of Papua New Guinea have provided the only information on yaws since 1978. These reports concentrated on outbreaks on Karkar Island in the Madang Province and indicated the possibility of a recurrence of yaws. It was not until early 1984, when further reports became available from other provinces in the country, that the national health department renewed its interest in yaws. Monthly reports are currently being collected from hospitals, health centres, and aid posts throughout the country. This effort was started in 1984, however, and no conclusions are available. The initiation of a nationwide survey seems inevitable at this stage. For this to be made possible, capital and appropriate manpower are needed.

Humans↗

PubMed1981

Yaws in rural Accra.

Thanks to a yaws control programme launched in Ghana in 1956, yaws morbidity decreased to below 0.2% in all the Regions of Ghana except the Eastern Region and some districts of the Western Region by 1962. However, there has since been progressive growth in yaws morbidity up to a present level of 0.6%, and this trend, should it continue, causes concern. Questionnaire forms were used to collect data on three most heavily affected villages and were completed for 20% of the adult population (above 15 years of age). Doubtful cases were referred to the author for verification directly, but the author also checked all evident cases detected by local examiners. Out of a total population of 1641, 443 persons were examined and given questionnaires. It was evident that the majority of the respondents (about 90%) were families with yaws; most of them had seen the disease but did not know its cause. Out of the 443 respondents, 235 (53%) said the cause was not known to them, 154 (34.7%) said it was dirt and 54 (12.2%) attributed yaws to a natural cause. The majority of the respondents were in agreement that, no matter what its cause, the disease can be transmitted by social contact. Yaws control programmes should be included in primary health programmes, so that the pertinent sanitary instruction, epidemiological surveillance and treatment could be freed of their heavy dependence on transport.

Adolescent↗

PubMed1999

The relationship between leg stepping pattern and yaw torque oscillations in curve walking of two crayfish species

Curve walking in two species of crayfish, Procambarus clarkii and Astacus leptodactylus, was investigated to test whether the mechanism underlying curve walking is the synchronous action of a centrally pre-programmed leg tripod or whether it is the action of one principal leg that produces the main body yaw torque. Curve walking was induced by an optomotor visual stimulus, and the yaw torque produced by the tethered animals was measured in open-loop conditions. Our main results suggest that the yaw torque oscillations in both P. clarkii and A. leptodactylus are related to the movement of outer leg 4 (i.e. leg 4 on the outside of the turn). That is, the peaks in the yaw torque occur, on average, in synchrony with the power stroke of outer leg 4. When comparing the results of this open-loop experiment on P. clarkii with results previously obtained for curve walking in untethered individuals of the same species, we found a much higher variability in leg coordination in the open-loop situation. Similarly, here we did not find the same level of synchrony in the tripod (formed by outer leg 4 and inner legs 2 and 5) observed during untethered free walking. Therefore, we suggest that tethered conditions may diminish the need for stability and thus allow outer leg 4 to produce a body rotation regardless of the leg stepping configuration. The characteristics of leg 4 are in line with its major role in turning. According to previous studies, legs 4 provide the largest force and the largest step amplitude during walking, and their force includes both a pulling and a pushing component which can facilitate the control of turning. Although it is apparent that outer leg 4 is not the only leg that can produce an inward yaw torque, its major role in modulating the yaw torque suggests that there may be a specific, centrally generated control of outer leg 4 during curve walking in crayfish.

Journal Article↗

PubMed1955

Serological study of yaws in Java.

This report presents the results of serological analyses made by the laboratory of the Treponematoses Control Project, Indonesia, from its establishment in April 1951 until April 1953. All sera were tested quantitatively with the VDRL and Kline slide-tests or the Kahn test, or with all three.A study of the mean reagin titre in untreated yaws cases showed that the percentage of seronegative reactors among clinically positive cases was low. Less seronegativity was observed among females than males.EXAMINATION OF DECREASE IN MEAN REAGIN TITRE AFTER TREATMENT BY CLINICAL GROUP SHOWED MAXIMUM TO MINIMUM DECREASE IN THE FOLLOWING SEQUENCE: early contagious, early contagious plus hyperkeratosis, ulcerative plus osteo-articular, ulcerative, hyperkeratosis, and osteo-articular lesions. The decrease tended to be greater in females than males and in patients with high than with low titre; it also varied with the age of the patient. No significant variation in decrease was noted when four different PAM treatment schedules were tested comparatively. The percentage of serological cure and improvement with all schedules was highest in the cases with early lesions, and in the younger age-groups.A study of patients requiring re-treatment at the time of resurvey showed no important difference in mean reagin titre between clinically cured and uncured patients suffering from palmar or plantar hyperkeratosis and ulcerative or osteo-articular lesions.Serological testing of sera from clinically negative household contacts and non-contacts, with or without previous history of yaws, gave the following results: Among the household contacts, the number of seronegative reactors, while not affected by age-distribution, was significantly higher in the history-positive than in the history-negative groups. The percentage of seropositive reactors was in direct proportion to the prevalence of yaws, the seropositivity-rate being high in villages with a yaws incidence of 11%-30%.The report also contains suggestions for improving the conduct of the anti-yaws campaign.

Age Distribution↗

PubMed2026

Effect of repeated mass drug administration on the transmission of yaws: a retrospective genomic epidemiology study.

BACKGROUND: Yaws, a neglected tropical disease caused by Treponema pallidum subspecies pertenue (T p pertenue), has evaded eradication, in part due to a high proportion of asymptomatic cases. Repeated mass drug administration (MDA), whereby an entire population is repeatedly treated irrespective of disease, could provide a solution. Here, we aimed to investigate the effect of MDA on the genomic epidemiology of T p pertenue. METHODS: We conducted a retrospective genomic epidemiology study on samples collected during a cluster-randomised trial of mass administration of azithromycin for yaws eradication in the Namatanai District of Papua New Guinea. Participants were in 38 wards (administrative units encompassing several villages) in three local-level government areas (LLGs). The experimental group received an initial round of MDA followed by two further rounds 6 months and 12 months after the first round. The control group received one round of MDA followed by two rounds of treatment targeting clinical cases and contacts only, on the same schedule as the MDA in the experimental group. A follow-up survey on both groups was done 18 months after the first MDA round. Swab samples were collected at each round from ulcerative and nodular skin lesions, and blood was collected by finger-prick for serological testing at 18 months. Metadata on ulcer size (cm) and duration (days) were recorded at each round, and treponemal and non-treponemal antibodies were recorded at 18 months. Samples from swabs positive for T p pertenue underwent library preparation and whole-genome sequencing. We examined the phylogenetic relationships between genomes, linking them with geospatial and patient metadata to understand the impact of MDA on T p pertenue diversity and transmission. FINDINGS: Swabs collected from 297 individuals with active yaws from April 30, 2018, to Nov 2, 2019, yielded 222 good-quality Tp pertenue genomes. We identified 20 sublineages of T p pertenue in the control group and 21 in the experimental group at the beginning of the study. At the end of the study, there were 13 sublineages in the control group and three in the experimental group, of which two persisted in both groups. Three sublineages not detected at baseline were observed in the control group after commencing MDA. The two sublineages that persisted in both groups had non-synonymous mutations in penicillin-binding proteins. One of these sublineages evolved macrolide resistance in three individuals and was associated with lowered treponemal antibody (p=0·0036) and longer ulcer duration (p=0·015). Despite the study taking place within a small island, sublineages were geographically clustered, with pairs of samples from the same ward (odds ratio 7·1, 95% CI 5·7-8·8; p<0·0001) or neighbouring wards (4·3, 3·3-5·4; p<0·0001) more likely to share the same sublineages compared with pairs from different LLGs. Additionally, older individuals were more likely to share sublineages than were younger individuals (1·5, 1·2-1·9; p<0·0001). INTERPRETATION: Repeated MDA was successful in reducing and maintaining the genetic diversity of T p pertenue at a low level but was associated with the development of macrolide resistance. Yaws re-emergence after MDA was attributed to multiple sublineages, of which the majority were detected in the population before MDA. Participants within the same ward were more likely to share sublineages than those that were more widely geographically separated, suggesting that re-emergence was driven by local transmission. These findings could inform future yaws elimination strategies. FUNDING: European Research Council, EU, Provincial Deputation of Barcelona, Barberà Solidària Foundation, Wellcome, and Fundació "la Caixa".

Adolescent↗

PubMed1999

Yaws and syphilis in the Garkida area of Nigeria.

Sixty-four (4.2%) cases of yaws and forty-one (2.7%) cases of syphilis were encountered during an epidemiological survey for filariasis in the mid-Hawal river valley. This finding is despite the official position that yaws has been eradicated in Nigeria. The focus of the disease was localised in four of the six villages that were surveyed in the Garkida area of the valley. The disease was more common among farmers than among occupational groups. Aspart from yaws, syphilis (2.7%) which is another treponematoid infection was also encountered during the filariasis survey. The present findings imply that there still exists a benign transmission of the disease in the area and unless an immediate and effective control programme is initiated, yaws may still become a very important disease in Nigeria. The epidemiological aspects and public health implication of treponematosis especially of yaws, in this area are discussed.

Adult↗

PubMedDate not supplied

Some epidemiologic aspects of yaws in the Ivory Coast.

Because of the prevailing high levels of yaws, a mass treatment campaign was conducted in the Ivory Coast from 1956 to 1970. In 1970, at the end of the mass campaign, less than 30,000 cases of yaws were reported. After 1970, a program of detection and treatment of remaining foci of infection was carried out to control the disease. The number of cases reported annually continued to decline until 1974, when the number of reported cases began to rise. Since 1980, the annual reported incidence of yaws has declined. It is concluded that the mass campaign of 1956-1970 reduced the endemicity of yaws in the Ivory Coast. However, significant foci of the disease remain, and efforts to detect and treat yaws must be continued to prevent a resurgence of this infection in the Ivory Coast.

Cote d'Ivoire↗

PubMedDate not supplied

Yaws in Suriname.

Frambesia tropica, or yaws, is still prevalent in the urban population of some of the districts in Suriname. In 1911 a campaign against yaws, probably the first such campaign in the world involving treatment with salvarsan, was organized. It resulted in the rapid cure of all hospitalized patients. As a consequence of this success, the disease became less important to the medical authorities in the country. After introduction of penicillin (1945) for the treatment of yaws, the disease almost disappeared in Suriname. After 1970 new cases were diagnosed, and the resurgence of yaws in Suriname became apparent. The symptoms in these cases were attenuated in comparison to those described in standard handbooks. A survey of yaws in the different districts of Suriname was undertaken to determine the prevalence of the disease and its spread through the country in order to plan a new treatment campaign.

Adolescent↗

PubMed1977

Pinta, yaws, and venereal syphilis in Colombia.

Three treponemal infections of man have coexisted in Colombia, South America for centuries. In former years, Colombia and Mexico were the world's most highly endemic countries for pinta. Within Colombia, highest rates of infection with pinta occurred among the mestizo and Indian populations in the Andean and Caribbean departments of Huila, Tolima, Antiochia, Magdalena and Cesar. Yaws occurred primarily in rural areas along the Pacific coast among descendants of African slaves. Infectious syphilis is most often reported from the three largest urban areas, and from three other densely populated departments in the Andean region. During the 21-year period from 1954 to 1974, almost four times as many cases of pinta as yaws were reported. The incidence rates of yaws and pinta have declined almost in parallel in Colombia, even though there has been a national campaign against yaws, but not against pinta. The incidence of primary and secondary syphilis increased only slightly during the same period. The total burden of reported treponematoses (excluding tertiary and congenital syphilis) declinded by over 40 per cent, while the ratios of reported yaws, pinta and infectious syphilis rose from 1:3:4 in 1954 to 1:7:975 in 1974.

Colombia↗

PubMed1992

A small yaws survey on the island of Sumatra, Indonesia.

Yaws (framboesia tropica), caused by Treponema pallidum subspecies pertenue, is a chronic infectious disease, found in tropical rural regions. As a result of mass treatment campaigns conducted in the 1950s and 1960s the prevalence of yaws and the other endemic treponematoses (pinta and endemic syphilis) has decreased greatly. However, in several tropical regions in the world resurgence of yaws was reported in the 1980s. In this article we present the results of a small survey on yaws in six health centres in the Pariaman region in West Sumatra, Indonesia. A general conclusion from this small survey is that yaws is far from being eradicated and that in this region the disease is on the increase again. Some major findings of T. pertenue research are presented here.

Adolescent↗

PubMed1985

[Extent of endemic yaws in Upper Volta in 1981].

This yaws investigation has been realized in the South West of Upper-Volta, in 1981, in areas around Gaoua, Niangoloko, N'Dorola; this investigation concerns 15 villages, chosen at random, and a sample of 1540 persons older than 4 years. The clinical prevalence (infectious cases) is 0.6%; the higher prevalence is observed around Gaoua (1.5%). Infectious contagious lesions are found especially in the 5-14 years old group. This investigation shows a low prevalence (under 5%) of active yaws. The serological prevalence (Kline-test) is 5.8% and we observe also around Gaoua the highest prevalence (8%). Periodical screening surveys of the population, during years 1952-1957, had shown a low prevalence of yaws, with a medium prevalence of yaws around Gaoua. Yaws treatment campaigns had been realized from 1957 to 1960 in South-West of Upper-Volta with very good results (prevalence: 0.06% - 1960). Now, in 1981, we note a resurgence of endemic foci, especially around Gaoua, from where the infection is spreading again, this, threatening the gains made by previous mass treatment campaigns. Taking in account the present result, it is necessary to treat contagious cases and contact sick persons (selective mass treatment or S.M.T., recommended in areas of low prevalence, by the WHO scientific group on treponemal infections).

Adolescent↗

PubMed1994

Recurrence of yaws outbreak in Thailand, 1990.

In November 1990, an outbreak of yaws was reported in a rural village of southern Thailand. A survey consisting of history taking, physical examination and blood tests for VDRL and TPHA was undertaken in the whole village and in the primary school of the village. A yaws case was defined as a person who had a positive VDRL confirmed by TPHA without history of other treponemal infection or post-treatment of yaws. Fifty-four cases, an attack rate of 23%, were found in the age range from 2 to 79 years old. The epidemic curve started with a few cases in 1989 and early 1990 with an increasing number of cases from June, and reached its peak in November. Half of the cases (53.7%) were children under 15 years. Male cases were higher than female (1.5:1). A survey of 105 primary school students found an attack rate of 32% (34/105) and the prevalence was higher in younger classes. Benzathine penicillin injection was given to cases for treatment. From this investigation, the Ministry of Public Health was alerted about the recurrence of yaws. Strengthening health education and surveillance activities was recommended in adjacent districts and provinces. The extent of the problem was assessed through surveys among school children and expanded to their family members if cases of yaws were found.

Adolescent↗

PubMed2006

Localization of the subjective vertical during roll, pitch, and recumbent yaw body tilt.

Localization of the subjective vertical during body tilt in pitch and in roll has been extensively studied because of the relevance of these axes for aviation and control of posture. Studies of yaw orientation relative to gravity are lacking. Our goal was to perform the first thorough evaluation of static orientation in recumbent yaw and to collect as efficiently as possible roll and pitch orientation data which would be consistent with the literature, using the same technique as our yaw tests. This would create the first comprehensive, coherent data set for all three axes suitable for quantitative tri-dimensional modeling of spatial orientation. We tested localization of the vertical for subjects tilted in pitch (-100 degrees to +130 degrees ), in roll (-90 degrees to +90 degrees ), and in yaw while recumbent (-80 degrees to +80 degrees ). We had subjects point a gravity-neutral probe to the gravitational vertical (haptically indicated vertical) and report verbally their perceived tilt. Subjects underestimated their body tilts in recumbent yaw and pitch and overestimated their tilts in roll. The haptic settings for pitch and roll were consistent with data in the literature obtained with haptic and visual indications. Our data constitute the first tri-dimensional assessment of the subjective vertical using a common measurement procedure and provide the basis for the tri-axial modeling of vestibular function presented in the companion paper.

Adult↗