Coinfection of a yaws patient with two closely related Treponema pallidum subsp. pertenue strains: A rare event with potential evolutionary implications.

The etiological agent of yaws is the spirochete Treponema pallidum (TP) subsp. pertenue (TPE) and infects the children of Papua New Guinea, causing ulcerative skin lesions that impairs normal growth and development. Closely related strains of Treponema pallidum subsp. pertenue, JE11, and TE13 were detected in an ulcer biospecimen derived from a 5-year-old yaws patient. Cloning experiments validated the presence of two distinct but similar genotypes, namely TE13 and JE11, co-occurring within a single host. While coinfection with highly related TPE strains has only limited epidemiological and clinical relevance, this is the first documented coinfection with genetically distinct TP strains in a single patient. Similar coinfections in the past were explained by the existence of over a dozen recombinant loci present in the TP genomes as a result of inter-strain or inter-subspecies recombination events following an anticipated scenario of TP coinfection, i.e., uptake of foreign DNA and DNA recombination.

Using 16s rRNA sequencing to characterize the microbiome of tropical cutaneous ulcer disease: insights into the microbial landscape and implications for diagnosis and treatment.

Cutaneous ulcers are common in yaws-endemic areas. Although often attributed to 'Treponema pallidum subsp. pertenue' and Haemophilus ducreyi, quantitative PCR has highlighted a significant proportion of these ulcers are negative for both pathogens and are considered idiopathic. This is a retrospective analysis utilising existing 16S rRNA sequencing data from two independent yaws studies that took place in Ghana and the Solomon Islands. We characterized bacterial diversity in 38 samples to identify potential causative agents for idiopathic cutaneous ulcers. We identified a diverse bacterial profile, including Arcanobacterium haemolyticum, Campylobacter concisus, Corynebacterium diphtheriae, Staphylococcus spp. and Streptococcus pyogenes, consistent with findings from previous cutaneous ulcer microbiome studies. No single bacterial species was universally present across all samples. The most prevalent bacterium, Campylobacter ureolyticus, appeared in 42% of samples, suggesting a multifactorial aetiology for cutaneous ulcers in yaws-endemic areas. This study emphasizes the need for a nuanced understanding of potential causative agents. The findings prompt further exploration into the intricate microbial interactions contributing to idiopathic yaw-like ulcers, guiding future research toward comprehensive diagnostic and therapeutic strategies.

Implementation of an integrated control programme for neglected tropical diseases of the skin in Ghana: The essential role of the laboratory.

Introduction: In this study, we report on findings from approaches used, the outcomes and the lessons learnt from the laboratory support provided for integrated control of skin NTDs including Buruli ulcer (BU), and yaws in seven selected districts in Ghana. Methods: Actions implemented from July 2018 to October 2022 included; training district-level health workers on specimen collection, storage, and transport to laboratories, integrated case searches, continual monitoring and supervision for trained health workers, laboratory confirmation of BU and yaws samples and providing results of the analysed samples to guide decision making. Descriptive analysis of data was performed. Results: A total of 18,683 (including suspected BU 976; suspected yaws 10,995) individuals were screened for BU and yaws. Of 976 suspected BU cases, 16.8% [median (IQR) age 24 (12.0-37.8) years] were confirmed positive by IS2404 PCR; BU mostly presented as ulcers (78.7%); category I (37.2%) and category II (36%). 480 individuals (4.4%) had DPP positive yaws. Multiplex PCR analysis of 75 selected DPP positive cases identified; 7 DPP positive yaws cases as Treponema pallidum, 28 as Haemophilus ducreyi and 7 as Treponema pallidum/Haemophilus ducreyi coinfection. Laboratory results were sent to the districts within a median (IQR) of 5 (3 - 9) days. Conclusion: The implementation of integrated diagnostic confirmation for skin NTDs is feasible with provision of timely results within a week. Multiplex diagnostic tools differentiated Treponema pallidum and Haemophilus ducreyi. There is a need to sustain active case search activities, enhance health worker training, and improve laboratory confirmation of cases as part of the overall strategy for the integrated control of skin neglected tropical diseases.

Prospecting for yaws in the Mbaïki Health District in the Central African Republic.

Introduction: yaws is endemic in the Central African Republic. The last cases of yaws notified by CAR to WHO date back to 2012. The objective of this study was to measure the prevalence of yaws in the health district of Mbaïki and to describe its clinical and epidemiological characteristics. Methods: this is a descriptive cross-sectional study, conducted from April 10 to 18, 2020 in the Mbaïki health district. Yaws cases were sought in 570 households in the 38 selected villages of the district. Any consenting individual over the age of one year with yaws-like skin lesions was a suspected case of yaws and included in the study. Blood was taken from suspected cases for serological testing (TDR, RPR and TPHA). Any suspected case of yaws with positive RPR and TPHA was considered a confirmed case. Results: a total of 1967 people were examined, of whom 113 were considered suspected cases of yaws. All suspected cases were RPR-positive, 41 TPHA-positive and 13 RDT-positive. Forty-one cases of yaws were confirmed in 18 (47.37%) villages. The prevalence of yaws in the Mbaïki health district was 2.08%. Among the cases, 38.94% were children aged 1 to 14. The sex ratio was 1.69. Lesions clinically suggestive of yaws were papilloma-like in 77.00% of cases, followed by micropapules (8.00%) and ulcerations (5.00%). Conclusion: eight of the nine communes in the Mbaïki health district are yaws-endemic. This result suggests the need to implement the Morges strategy in the Mbaïki health district.

Rapid Serologic Test for Diagnosis of Yaws in Patients with Suspicious Skin Ulcers.

The Chembio DPP (Dual Path Platform) Syphilis Screen & Confirm kit (https://chembio.com) is a rapid serologic test that can be used to diagnose yaws. We evaluated its capacity to detect patients with ulcers that tested PCR positive for Treponema pallidum subsp. pertenue. DPP detected 84% of ulcers that were positive by PCR.

Yaws in Pygmy and Bantu children inhabiting the rural zones of Central Africa.

Introduction: Yaws, an infectious dermatosis is one of 17 neglected tropical diseases still present in the world despite the efforts aiming at the eradication of the disease undertaken in 2020. It is mainly found in populations living in poor hygiene conditions with a limited access to water and health care facilities. BaAka Pygmies and Bantu people inhabiting the rural areas of the Central African Republic (CAR) are still affected by yaws on a large scale. Aim: To assess the prevalence of yaws in Central Africa, treatment accessibility, and the need for implementing future health programs. Material and methods: Primary school BaAka Pygmy and Bantu children from the Dzanga Sangha region (CAR) were assessed in the context of yaws prevalence in years 2019-2020. The diagnosis was based on the clinical picture of the typical skin lesions and their location. Serologic tests were not performed. Results: Four hundred and ninety-four Pygmies and 235 Bantu children were examined, of whom 38.7% and 43.0%, respectively, presented primary yaws lesions. The mean age of Pygmy and Bantu children with lesions was 9.1 and 9.7 years old, respectively. In both ethnic groups boys predominated. The most common location of yaws lesions were lower legs, ankles, knees and feet. Conclusions: Yaws, like all other neglected tropical diseases, might become a cosmopolitan skin disease transferred from Africa to Europe and North America by tourists travelling to sub-Saharan destinations in Africa and migrants. The knowledge of tropical skin diseases and ability to make a differential diagnosis might become necessary for each dermatologist in the next 10-20 years.

Mathematical modelling Treponema infection in free-ranging Olive baboons (Papio anubis) in Tanzania.

Yaws is a chronic infection caused by the bacterium Treponema pallidum susp. pertenue (TPE) that was thought to be an exclusive human pathogen but was recently found and confirmed in nonhuman primates. In this paper, we develop the first compartmental ODE model for TPE infection with treatment of wild olive baboons. We solve for disease-free and endemic equilibria and give conditions on local and global stability of the disease-free equilibrium. We calibrate the model based on the data from Lake Manyara National Park in Tanzania. We use the model to help the park managers devise an effective strategy for treatment. We show that an increasing treatment rate yields a decrease in disease prevalence. This indicates that TPE can be eliminated through intense management in closed population. Specifically, we show that if the whole population is treated at least once every 5-6 years, a disease-free equilibrium can be reached. Furthermore, we demonstrate that to see a substantial decrease of TPE infection to near-elimination levels within 15 years, the whole population needs to be treated every 2-3 years.

Improved rapid diagnostic tests to detect syphilis and yaws: a systematic review and meta-analysis.

BACKGROUND: Current rapid tests for syphilis and yaws can detect treponemal and non-treponemal antibodies. We aimed to critically appraise the literature for rapid diagnostic tests (RDTs) which can better distinguish an active infection of syphilis or yaws. METHODS: We conducted a systematic review and meta-analysis, searching five databases between January 2010 and October 2021 (with an update in July 2022). A generalised linear mixed model was used to conduct a bivariate meta-analysis for the pooled sensitivity and specificity. Heterogeneity was assessed using the I2 statistic. We used the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) to assess the risk of bias and Grading of Recommendations, Assessment, Development and Evaluations (GRADE) to evaluate the certainty of evidence. RESULTS: We included 17 studies for meta-analyses. For syphilis, the pooled sensitivity and specificity of the treponemal component were 0.93 (95% CI: 0.86 to 0.97) and 0.98 (95% CI: 0.96 to 0.99), respectively. For the non-treponemal component, the pooled sensitivity and specificity were 0.90 (95% CI: 0.82 to 0.95) and 0.97 (95% CI: 0.92 to 0.99), respectively. For yaws, the pooled sensitivity and specificity of the treponemal component were 0.86 (95% CI: 0.66 to 0.95) and 0.97 (95% CI: 0.94 to 0.99), respectively. For the non-treponemal component, the pooled sensitivity and specificity were 0.80 (95% CI: 0.55 to 0.93) and 0.96 (95% CI: 0.92 to 0.98), respectively. CONCLUSIONS: RDTs that can differentiate between active and previously treated infections could optimise management by providing same-day treatment and reducing unnecessary treatment. PROSPERO REGISTRATION NUMBER: CRD42021279587.

Quantifying Population Burden and Effectiveness of Decentralized Surveillance Strategies for Skin-Presenting Neglected Tropical Diseases, Liberia.

We evaluated programmatic approaches for skin neglected tropical disease (NTD) surveillance and completed a robust estimation of the burden of skin NTDs endemic to West Africa (Buruli ulcer, leprosy, lymphatic filariasis morbidity, and yaws). In Maryland, Liberia, exhaustive case finding by community health workers of 56,285 persons across 92 clusters identified 3,241 suspected cases. A total of 236 skin NTDs (34.0 [95% CI 29.1-38.9]/10,000 persons) were confirmed by midlevel healthcare workers trained using a tailored program. Cases showed a focal and spatially heterogeneous distribution. This community health worker‒led approach showed a higher skin NTD burden than prevailing surveillance mechanisms, but also showed high (95.1%) and equitable population coverage. Specialized training and task-shifting of diagnoses to midlevel health workers led to reliable identification of skin NTDs, but reliability of individual diagnoses varied. This multifaceted evaluation of skin NTD surveillance strategies quantifies benefits and limitations of key approaches promoted by the 2030 NTD roadmap of the World Health Organization.

Stigma, psychosocial and economic effects of yaws in the Philippines: an exploratory, qualitative study.

BACKGROUND: Yaws is a chronic, non-venereal, highly contagious skin and bone infection affecting children living in impoverished, remote communities and caused by Treponema pallidum subspecie pertenue. Social stigma and economic losses due to yaws have been reported anecdotally in the Southern Philippines but have not been well-documented. OBJECTIVE: To describe and compare the psychological, social, and economic effects of yaws from the perspective of patients, contacts, and key informants in two areas of the Philippines. MATERIALS AND METHODS: Yaws and contacts were identified through clinicoseroprevalence surveys conducted in the Liguasan Marsh area, Mindanao, Southern Philippines in 2017 and among the Aetas, an indigenous people community in Quezon province, Luzon region in 2020. Skin examinations and serologic tests confirmed the diagnosis of active, latent, or past yaws among the children and adults. Trained health personnel conducted in-depth interviews of those affected by yaws and their guardians, household contacts, and key informants, such as health workers regarding their perceptions, feelings, health-seeking behaviors, and effects of yaws on their lives. RESULTS: A total of 26 participants were interviewed: 17 from Mindanao and 9 from Luzon. Aside from the physical discomforts and embarrassment, yaws was considered stigmatizing in Mindanao, because positive non-treponemal tests or treponemal antibody tests were associated with syphilis and promiscuity. These have led to loss of employment and income opportunities for adults with latent or past yaws. In contrast, the Aetas of Luzon did not perceive yaws as stigmatizing, because it was a common skin problem. Plantar yaws interfered with the Aeta's gold panning livelihood due to the pain of wounds. CONCLUSIONS: Yaws is not merely a chronic skin and bone disease. It can lead to significant psychosocial and economic problems as well. Yaws is a generally forgotten disease in the Philippines. There is no yaws surveillance and control program. Treatments are not readily available for the populations affected, thus perpetuating the infection and negative effects. SIGNIFICANCE OF STUDY: This is the first study to document the psychosocial and economic effects of yaws among Filipinos. Information campaigns about yaws and a yaws control program are needed to reduce stigma and discrimination.

A simple, high-throughput and validated LC-MS/MS method for the determination of azithromycin in human plasma and its application to a clinical pharmacokinetic study.

A sensitive, specific and rapid liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method was developed and validated to quantify azithromycin concentrations in human plasma. Azithromycin (AZI) is the most common outpatient prescribed antibiotic in the US and clinical studies have demonstrated the efficacy and safety of AZI in many bacterial infections. To support a clinical study, we developed a high-throughput LC-MS/MS method to process up to 250 samples per day to quantify AZI in human plasma. Samples were prepared by solid-phase extraction. Separation was achieved with an ACE C18 column (2.1 × 100 mm, 1.7 µm) equipped with a C18 guard column. The mobile phase consisted of 0.1% formic acid and methanol-acetonitrile (1:1, v/v) at a flow rate of 0.25 ml/min. The ionization was optimized with positive electrospray source using multiple reaction monitoring transition, m/z 749.50 > 591.45 for AZI and m/z 754.50 > 596.45 for AZI-d5. Extraction recoveries were approximately 90% for AZI. The assay was linear from 0.5 to 2,000 ng/ml and required only 100 µl of plasma with a total analysis time of 4.5 min. The method was successfully applied to pharmacokinetic studies of a weight-based dosing protocol for AZI.

An ODE model of yaws elimination in Lihir Island, Papua New Guinea.

Yaws is a chronic infection that affects mainly the skin, bone and cartilage and spreads mostly between children. The new approval of a medication as treatment in 2012 has revived eradication efforts and now only few known localized foci of infection remain. The World Health Organization strategy mandates an initial round of total community treatment (TCT) with single-dose azithromycin followed either by further TCT or by total targeted treatment (TTT), an active case-finding and treatment of cases and their contacts. We develop the compartmental ODE model of yaws transmission and treatment for these scenarios. We solve for disease-free and endemic equilibria and also perform the stability analysis. We calibrate the model and validate its predictions on the data from Lihir Island in Papua New Guinea. We demonstrate that TTT strategy is efficient in preventing outbreaks but, due to the presence of asymptomatic latent cases, TTT will not eliminate yaws within a reasonable time frame. To achieve the 2030 eradication target, TCT should be applied instead.

Safety of mass drug coadministration with ivermectin, diethylcarbamazine, albendazole, and azithromycin for the integrated treatment of neglected tropical diseases: a cluster randomized community trial.

INTRODUCTION: Neglected tropical diseases control programmes run separately. For settings with more than one endemic disease, combined mass drug administration (MDA) has potential practical advantages compared with separate programmes but needs confirmation of safety. We assessed the safety of combined MDA for multiple neglected tropical diseases using ivermectin, diethylcarbamazine, albendazole (IDA) and azithromycin (AZI). METHODS: We conducted an open-label, cluster-randomized trial involving individuals living in 34 wards (smaller administrative division) in two study sites, Namatanai District and Lihir Island, Papua New Guinea. We randomly assigned wards to the combined treatment arm (which received a single dose of the triple combination IDA and a single dose of AZI at the same visit) or the control arm (which received IDA separately followed by AZI separately one week after). All participants underwent safety assessments one day after drug administration. Methodology for collecting the adverse events (AEs) was a general question (in Namatanai) and individual questions about specific AEs (in Lihir). The primary endpoint was the prevalence of AEs. Safety of combined treatment was taken to be non-inferior to that of IDA if the upper limit of the two-sided CI for the difference in rates was equal or lower than 5%. FINDINGS: The study enrolled 15,656 participants. Of those enrolled, 7,281 (46.3%) received the combined regimen and 8,375 (53.3%) received standard treatment with IDA for lymphatic filariasis between Nov 1, 2018, and Apr 15, 2019. Of the individuals in the control group, 4,228 (50.5%) attended a second visit one week apart to receive AZI for yaws. In Namatanai, the proportion of AEs was similar in the combined group (0.8%) compared to the IDA group (1.3%, difference 0.5% [95CI -2.5% to 1.4%]) or the AZI group (3.6%, d -2.8% [95CI -8.6% to 2.8%]). In Lihir, the proportion of AEs was higher in the combined group (23.0%) compared to the IDA group (12.2%, d 10.8% [95% CI 1.5% to 20.2%]) or the AZI group (11.1%, d 11.9% [95% CI 2.7% to 21.1%]).We observed 21 (0.3%) grade-2 AEs in the combined treatment group, 33 (0.4%) in the IDA separately group, and 18 (0.2%) in the AZI separately group. No participants required treatment for any AE. We observed no deaths, serious AEs, or AEs of special interest. INTERPRETATION: In the largest trial so far involving coadministration of regimens based on IDA and AZI, the combination was safe and feasible in a population of more than 15,000 people. Combined MDA based on these two regimens opens up new potential for the control of neglected tropical diseases in the Western Pacific region.

Conformity of yaws clinical features to combined rapid diagnostic test in children aged 2-15 years in an endemic area.

INTRODUCTION: The diagnosis of yaws is established by clinical examination and confirmed through a laboratory test. Unrecognized lesions may lead to a missed opportunity for diagnosis and complete eradication of yaws. The use of Dual Path Platform (DPP® RDT) Syphilis Screen and Confirm RDT (Chembio, Medford, New York) has been recommended by the World Health Organization (WHO) for endemic areas with limited laboratory facilities. To date, there have not been any studies assessing the conformity of clinical features based on the WHO guidelines with DPP® RDT. METHODOLOGY: A cross-sectional study was conducted to evaluate the conformity of yaws clinical features based on the WHO guidelines to the DPP® RDT. We recruited children aged 2-15 years old in Alor, Indonesia. All subjects underwent clinical examination and were tested with DPP® RDT. Fisher's exact test was used to analyze the overall agreement between the clinical features and the DPP® RDT results. RESULTS: A total of 197 study subjects (mean age 9 years) were enrolled. The most frequent skin lesion was a yaws scar (79.7%). Eight subjects (3%) were diagnosed with yaws based on the DPP® RDT examination. The overall agreement between clinical features and DPP® RDT was 26.9% (p = 0.202). CONCLUSIONS: The conformity of clinical features in suspected yaws to DPP® RDT is low; thus, clinical features should not be used as a sole initial reference in establishing yaws diagnosis, even in endemic areas.

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.

The Depiction of Smallpox and Other Dermatologic Lesions on the Surfaces of Ancient Terracotta Statues from Mali, West Africa.

Between 1100 A.D. and 1700 A.D., terracotta statues were created in the Interior Delta of the Niger River in what is now the Republic of Mali. They are known as Djenné-Jeno terracottas because of their geographic proximity to an ancient town of that name. Some of these statues possess surface excrescences that have long perplexed archaeologists, art historians, curators, and others. This study of these surface excrescences employed clinical, diagnostic, and epidemiological methodologies to elucidate their possible meanings. It has not been possible to ascribe these excrescences to a single cause. However, examination of all the evidence permitted consideration of several possibilities. These include diseases such as smallpox, onchocerciasis, and the secondary stage of venereal syphilis. On certain statues, the anatomic placement of excrescences possibly symbolizes intentional cicatrization that resulted in keloid formation which may have been a form of beautification.

How should Indonesia consider its neglected tropical diseases in the COVID-19 era? Hopes and challenges (Review).

During the coronavirus disease 2019 (COVID-19) pandemic, some countries, including Indonesia, have faced a double burden with regards to disease control. As Indonesia is a tropical country, it serves as a suitable host for disease vectors and multiple microorganisms of causative agents of disease. In total, five of the neglected tropical diseases (NTDs) should be a consideration in Indonesia during the COVID-19 pandemic, including leprosy, yaws, filariasis, soil-transmitted helminths and schistosomiasis. The present review summarises the preparedness of Indonesia in facing NTDs during the COVID-19 pandemic. Strengthening government leadership will be a valuable factor for combating NTDs in Indonesia. For instance, strong leadership can lead to precise management, by increasing the number of health facilities, engaging in active case identification, conducting health campaigns and instituting new regulations to prevent the stigmatization faced by patients. Preventive medicine in the first level of health facilities can be prioritized and presented to the community via health campaigns, health advocacy and improvement in follow-up after active case surveillance. Government-supported integrated management is also a key component in eliminating NTD. Moreover, healthy lifestyle campaigns that include social distancing, wearing a mask and regularly washing hands should be promoted continuously to reduce the transmission of COVID-19, which is potentially associated with a poor outcome in individuals with NTDs. This review concluded that the Indonesian government should strengthen their efforts toward NTD control using alternative methods, such as involving key citizens in the collaboration of the detection of new cases and introducing mobile health as a means of detecting health problems or following up on patient progress. To reduce the transmission of COVID-19, testing, tracing and treatment must be improved, so that the gap between suspected cases and confirmed cases of COVID-19 can be closed. If the transmission of COVID-19 can be decreased, case detection and efforts toward NTD control can be conducted effectively.

Prediction of sulfamerazine and sulfamethazine solubility in some cosolvent mixtures using non-ideal solution models / Predicción de la solubilidad de sulfamerazina y sulfametazina en algunas mezclas cosolventes utilizando modelos de solución no ideales / Predição da solubilidade de sulfamerazina e sulfametazina em algumas misturas de cosolventes usando modelos de solução não ideais

SUMMARY Introduction: Experimental Solubilities of sulfamerazine (SMR) and sulfamethazine (SMT) in some (methanol + water), (ethanol + water) and (1-propanol + water) cosolvent mixtures were collected from the literature at five temperatures from 293.15 to 313.15 K. Methodology: The results were analyzed with the van't Hoff, Apelblat modified, Buchowski-Ksiazaczak λh, van't Hoff-Yaws model, two-parameter Weibull function model. It was determined that the models that best describe the solubility of these sulfonamides in (alcohol + water) mixtures were the van't Hoff and Apelblat models, obtaining correlation indices greater than 0.99 in all cases. Results: The results obtained with the Modified Apelblat equation presents a high correlation index for the solubility of SMR and SMT in cosolvent mixtures, followed by the van't Hoff-Yaws model that presents a high fit of the estimated data with respect to the theoretical ones. According to the two-parameter Weibull function model, the solubility ofSMR and SMT in the co-solvent mixtures shows important deviations from ideality, which is consistent with the literature. The results are discussed in terms of the solute-solvent interactions that occur in this system.

RESUMEN Introducción: Las solubilidades experimentales de la sulfamerazina (SMR) y la sulfametazina (SMT) en algunas mezclas cosolvents (metanol + agua), (etanol + agua) y (1-propanol + agua), se revisaron en la literatura a cinco temperaturas de 293,15 a 313,15 K. Metodología: Los resultados se analizaron con el modelo van't Hoff, Apelblat modificado, Buchowski-Ksiazaczak λh, van't Hoff-Yaws, y el modelo de la función Weibull de dos parámetros. Se determinó que los modelos que mejor describen la solubilidad de estas sulfonamidas en mezclas (alcohol + agua) son los modelos de van't Hoffy Apelblat, obteniendo índices de correlación superiores a 0,99 en todos los casos. Resultados: Los resultados obtenidos con la ecuación de Apelblat modiicada presentan un alto índice de correlación para la solubilidad de SMR y SMT en mezclas de cosolventes, seguido del modelo van't Hoff-Yaws que presenta un alto ajuste de los datos calculados con respecto a los teóricos. Según el modelo de la función de Weibull de dos parámetros, la solubilidad de la SMR y la SMT en las mezclas de cosolventes muestra importantes desviaciones de las ideales, lo que es coherente con la literatura. Los resultados se discuten en términos de las interacciones soluto-solvente que se producen en este sistema.

RESUMO Introdução: As solubilidades experimentais de sulfamerazina (SMR e sulfametazina (SMT) em algumas misturas de cossolventes (metanol + água), (etanol + água) e (1-propanol + água), foram revisadas na literatura em cinco temperaturas de 293,15 a 313,15 K. Metodologia: Os resultados foram analisados com o modelo van't Hoff, Apelblat modificado, Buchowski-Ksiazaczak λh, van't Hoff-Yaws e o modelo de função Weibull de dois parâmetros. Determinou-se que os modelos que melhor descrevem a solubilidade dessas sulfonamidas em misturas (álcool + água) são os modelos van't Hoff e Apelblat, obtendo índices de correlação superiores a 0,99 em todos os casos. Resultados: Os resultados obtidos com a equação de Apelblat modi-icada apresentam um alto índice de correlação para a solubilidade de SMR e SMT em misturas de cosolventes, seguido pelo modelo de van't Hoff-Yaws que apresenta um alto ajuste dos dados calculados em relação a teóricos. De acordo com o modelo de função Weibull de dois parâmetros, a solubilidade de SMR e SMT em misturas de cosolventes apresenta desvios signiicativos dos ideais, o que é consistente com a literatura. Os resultados são discutidos em termos das interações soluto-solvente que ocorrem neste sistema.

Epidemiologic and Genomic Reidentification of Yaws, Liberia.

We confirmed endemicity and autochthonous transmission of yaws in Liberia after a population-based, community-led burden estimation (56,825 participants). Serologically confirmed yaws was rare and focal at population level (24 cases; 2.6 [95% CI 1.4-3.9] cases/10,000 population) with similar clinical epidemiology to other endemic countries in West Africa. Unsupervised classification of spatially referenced case finding data indicated that yaws was more likely to occur in hard-to-reach communities; healthcare-seeking was low among communities, and clinical awareness of yaws was low among healthcare workers. We recovered whole bacterial genomes from 12 cases and describe a monophyletic clade of Treponema pallidum subspecies pertenue, phylogenetically distinct from known TPE lineages, including those affecting neighboring nonhuman primate populations (Taï Forest, Côte d'Ivoire). Yaws is endemic in Liberia but exhibits low focal population prevalence with evidence of a historical genetic bottleneck and subsequent local expansion. Reporting gaps appear attributable to challenging epidemiology and low disease awareness.

Rethinking disease eradication: putting countries first.

There have been various infectious disease eradication programs implemented in various parts of the world with varying degrees of success since the early 1900s. Of all those programs, the one that achieved monumental success was the Smallpox Eradication Program (SEP). Most of the global health leaders and authorities that came up with the new idea of disease eradication in the 1980s tried to design and shape the new programs based on their experience in the SEP. The SEP had a very effective tool, vaccine, that did not require a cold chain system, and a relatively simple way of administration. The total cost of the eradication program was about US$300 million and the entire campaign took about 10 y. However, the Guinea worm and polio eradication programs that followed in the footsteps of SEP attained varying levels of success, consuming a huge amount of resources and taking a much longer time (>30 y each). This paper reviews the factors that played major roles in hindering the attainment of eradication goals and outlines possible recommendations for the way forward. Among other things, this paper strongly emphasizes that endemic countries should take the lead in all matters pertaining to making decisions for disease elimination and/or eradication initiatives and that 'elimination as a public health problem' is the preferred option rather than going for complete eradication at the expense of other health programs and thereby contributing to weakening of already fragile health systems, mainly in Africa.