Yaws: a second (and maybe last?) chance for eradication

Yaws: The forgotten tropical skin disease

Yaws is a rare skin disease endemic to tropical countries caused by Treponema pertenue. It is highly infectious and spreads through physical contact. In Malaysia, it was presumably eradicated during the 1960s, with the last reported case published in 1985. Due to its rarity, the disease often goes unrecognised and misdiagnosed. Here, we report the case of a 5-year-old aboriginal boy diagnosed with secondary yaws who presented with fever and an incidental finding of chronic painless ulcerated nodules and plaques on his lower limbs and gluteal region. His diagnosis was confirmed serologically with a venereal disease research laboratory lab test and he was successfully treated with a single dose of intramuscular benzathine penicillin G. Primary care physicians should not ignore this disease since its early recognition and appropriate treatment is vital to its eradication, especially in high-risk communities.

Agricultural expansion as risk to endangered wildlife: Pesticide exposure in wild chimpanzees and baboons displaying facial dysplasia

Prenatal exposure to environmental endocrine disruptors can affect development and induce irreversible abnormalities in both humans and wildlife. The northern part of Kibale National Park, a mid-altitude rainforest in western Uganda, is largely surrounded by industrial tea plantations and wildlife using this area (Sebitoli) must cope with proximity to human populations and their activities. The chimpanzees and baboons in this area raid crops (primarily maize) in neighboring gardens. Sixteen young individuals of the 66 chimpanzees monitored (25%) exhibit abnormalities including reduced nostrils, cleft lip, limb deformities, reproductive problems and hypopigmentation. Each pathology could have a congenital component, potentially exacerbated by environmental factors. In addition, at least six of 35 photographed baboons from a Sebitoli troop (17%) have similar severe nasal deformities. Our inquiries in villages and tea factories near Sebitoli revealed use of eight pesticides (glyphosate, cypermethrin, profenofos, mancozeb, metalaxyl, dimethoate, chlorpyrifos and 2,4-D amine). Chemical analysis of samples collected from 2014 to 2016 showed that mean levels of pesticides in fresh maize stems and seeds, soils, and river sediments in the vicinity of the chimpanzee territory exceed recommended limits. Notably, excess levels were found for total DDT and its metabolite pp'-DDE and for chlorpyrifos in fresh maize seeds and in fish from Sebitoli. Imidacloprid was detected in coated maize seeds planted at the edge the forest and in fish samples from the Sebitoli area, while no pesticides were detected in fish from central park areas. Since some of these pesticides are thyroid hormone disruptors, we postulate that excessive pesticide use in the Sebitoli area may contribute to facial dysplasia in chimpanzees and baboons through this endocrine pathway. Chimpanzees are considered as endangered by IUCN and besides their intrinsic value and status as closely related to humans, they have major economic value in Uganda via ecotourism. Identifying and limiting potential threats to their survival such be a conservation priority.

Eradicating successfully yaws from India: The strategy & global lessons

Yaws, a non-venereal treponematosis, affecting primarily the tribal populations, has been considered historically as one of the most neglected tropical diseases in the world. In 1996, India piloted an initiative to eradicate yaws based on a strategy consisting of active case finding through house-to-house search and treatment of cases and their contacts with long acting penicillin. Thereafter, the campaign implemented in all 51 endemic districts in 10 States of the country led to the achievement of a yaws-free status in 2004. In the post-elimination phase, surveillance activities accompanied by serological surveys were continued in the erstwhile endemic districts. These surveys carried out among children between the age of 1-5 yr, further confirmed the absence of community transmission in the country. The experience of India demonstrates that yaws can be eradicated in all endemic countries of Africa and Asia, provided that political commitment can be mobilized and community level activities sustained until the goal is achieved.

Prevalence of serological markers and risk factors for bloodborne pathogens in Salvador, Bahia state, Brazil

This study aimed to determine the prevalence of serological markers for HIV-1/2, HBV, HCV, Treponema cruzi and T. pallidum infections. The association of these infections with risk factors in a population from Salvador, Bahia, Brazil was also analysed. Of the 780 enrolled individuals, 545 (70%) were female and 235 (30%) were male. Seroprevalence of 0·8% (6/702), 1·3% (9/678), 1·5% (10/684), 3·5% (23/663) and 11·5% (77/668) for HIV-1/2, HBV, HCV, T. cruzi and T. pallidum infections, respectively, was observed. The seroprevalence of T. pallidum was higher in males 20% (43/210) than in females 7% (34/458) (P < 0·01). An association between age and seroprevalence for T. cruzi (P = 0·02) and T. pallidum (P < 0·01) was observed. HBsAg was associated with having tattoos (3/37 vs. 6/623, P = 0·01) and not having a steady sexual partner (5/141 vs. 4/473, P = 0·04), while anti-HIV-1/2 was associated with having tattoos (2/39 vs. 4/647, P = 0·04); however, larger studies are needed to categorically state the relationship of these risk factors with infectious agents. The prevalence of serological markers for HIV-1/2, HBV, HCV and T. cruzi was consistent with other studies.

Yaws in the Western pacific region: a review of the literature

Until the middle of the 20th century, yaws was highly endemic and considered a serious public health problem in the Western Pacific Region (WPR), leading to intensive control efforts in the 1950s–1960s. Since then, little attention has been paid to its reemergence. Its current burden is unknown. This paper presents the results of an extensive literature review, focusing on yaws in the South Pacific. Available records suggest that the region remains largely free of yaws except for Papua New Guinea, Solomon Islands, and Vanuatu. Many clinical cases reported recently were described as “attenuated”; advanced stages are rare. A single intramuscular injection of benzathine penicillin is still effective in curing yaws. In the Pacific, yaws may be amenable to elimination if adequate resources are provided and political commitment revived. A mapping of yaws prevalence in PNG, Solomon, and Vanuatu is needed before comprehensive country-tailored strategies towards yaws elimination can be developed.

Clinical outcome of skin yaws lesions after treatment with benzathinebenzylpenicillin in a pygmy population in Lobaye, Central African Republic

Background

Yaws is a bacterial skin and bone infectious disease caused by Treponema pallidum pertenue. It is endemic, particularly among pygmies in Central African Republic. To assess the clinical cure rate after treatment with benzathinepenicillin in this population, we conducted a cohort survey of 243 patients in the Lobaye region.

Findings and conclusion

The rate of healing of lesions after 5 months was 95.9%. This relatively satisfactory level of therapeutic response implies that yaws could be controlled in the Central African Republic. Thus, reinforcement of the management of new cases and of contacts is suggested.

Challenges in recognition and diagnosis of yaws in children in Papua New Guinea

A global resurgence of yaws in developing countries highlights the need for reliable diagnostic criteria for this neglected infection. We conducted a clinical and serologic survey of 233 children less than 15 years of age who had clinically suspected yaws. A total of 138 (59%) cases were confirmed serologically, and 10 of 12 primary stage cases showed positive results for Treponema pallidum by a polymerase chain reaction assay that has not yet been validated for identification of yaws. A high proportion of cases (46%) were in the secondary stage; 92% of them had osteoarticular involvement, and only 24% had a Venereal Disease Research Laboratory titer greater than 1:32.

Laboratory-confirmed case of yaws in a 10-year-old boy from the Republic of the Congo

We report a case of yaws in a patient with puritic cutaneous eruption who was initially suspected of infection with monkeypox. The diagnosis was established by real-time PCR and sequencing of specific treponemal DNA sequences. This is the first report describing the use of DNA sequencing to identify Treponema pallidum subsp. pertenue-specific sequences in a patient with active yaws.

Managing skin disease in resource-poor environments - the role of community-oriented training and control programs

Programs that have been devised to improve the lot of patients with skin disease, or disease presenting with skin signs and symptoms, in resource-poor regions have focused mainly on education and training or community-oriented control measures. However, both have in common an objective of managing disease at population level. Training has been delivered in different ways both by direct teaching for varying periods of time or by web-based and electronic communication; control measures have been less in evidence and there is a great need for more support from funding agencies. Despite this, there is now a growing number of successful initiatives in health improvement for skin conditions that cover many parts of the world. This report describes many of these schemes as an example of what can be done to help patients.

Outcome predictors in treatment of yaws

To estimate failure rates after treatment with benzathine penicillin and to identify determinants of failure that affected outcomes for yaws, we conducted a cohort study of 138 patients; treatment failed in 24 (17.4%). Having low initial titers on Venereal Disease Research Laboratory test and living in a village where yaws baseline incidence was high were associated with increased likelihood of treatment failure.

Secondary yaws: an endemic treponemal infection

Although yaws is rare in developed countries, as worldwide travel has become commonplace, it is essential to recognize this condition when evaluating patients who traveled from endemic regions. Herein, we discuss a case of secondary yaws presenting as extensive expanding annular lesions to raise awareness of this condition.

Prevalence study of yaws in the Democratic Republic of Congo using the lot quality assurance sampling method

BACKGROUND

Until the 1970s the prevalence of non-venereal trepanomatosis, including yaws, was greatly reduced after worldwide mass treatment. In 2005, cases were again reported in the Democratic Republic of the Congo. We carried out a survey to estimate the village-level prevalence of yaws in the region of Equator in the north of the country in order to define appropriate strategies to effectively treat the affected population.

METHODOLOGY/PRINCIPAL FINDINGS

We designed a community-based survey using the Lot Quality Assurance Sampling method to classify the prevalence of active yaws in 14 groups of villages (lots). The classification into high, moderate, or low yaws prevalence corresponded to World Health Organization prevalence thresholds for identifying appropriate operational treatment strategies. Active yaws cases were defined by suggestive clinical signs and positive rapid plasma reagin and Treponema pallidum hemagglutination serological tests. The overall prevalence in the study area was 4.7% (95% confidence interval: 3.4-6.0). Two of 14 lots had high prevalence (>10%), three moderate prevalence (5-10%) and nine low prevalence (<5%.).

CONCLUSIONS/SIGNIFICANCE

Although yaws is no longer a World Health Organization priority disease, the presence of yaws in a region where it was supposed to be eradicated demonstrates the importance of continued surveillance and control efforts. Yaws should remain a public health priority in countries where previously it was known to be endemic. The integration of sensitive surveillance systems together with free access to effective treatment is recommended. As a consequence of our study results, more than 16,000 people received free treatment against yaws.