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result(s) for
"Yaw"
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Yaws Circulating in Nonhuman Primates, Uganda and Rwanda
2025
The bacterium Treponema pallidum pertenue causes yaws in humans and nonhuman primates. We describe 33% T. pallidum pertenue seropositivity in 9 species of nonhuman primates in Uganda and Rwanda, seroconversion during a lethal outbreak and a novel bacterial genomic lineage. Yaws may threaten both public health and conservation in the region.
Journal Article
Yaws
by
Asiedu, Kingsley
,
Mabey, David
,
Mitjà, Oriol
in
Africa
,
Anti-Bacterial Agents - therapeutic use
,
Asia
2013
Yaws is an infectious disease caused by Treponema pallidum pertenue—a bacterium that closely resembles the causative agent of syphilis—and is spread by skin-to-skin contact in humid tropical regions. Yaws causes disfiguring, and sometimes painful lesions of the skin and bones. As with syphilis, clinical manifestations can be divided into three stages; however, unlike syphilis, mother-to-child transmission does not occur. A major campaign to eradicate yaws in the 1950s and 1960s, by mass treatment of affected communities with longacting, injectable penicillin, reduced the number of cases by 95% worldwide, but yaws has reappeared in recent years in Africa, Asia, and the western Pacific. In 2012, one oral dose of azithromycin was shown to be as effective as intramuscular penicillin in the treatment of the disease, and WHO launched a new initiative to eradicate yaws by 2020.
Journal Article
A dynamic model of wind turbine yaw for active farm control
by
Meneveau, Charles
,
Starke, Genevieve M.
,
King, Jennifer R.
in
controls oriented modeling
,
Deformation analysis
,
Dynamic models
2024
This paper presents a graph‐based dynamic yaw model to predict the dynamic response of the hub‐height velocities and the power of a wind farm to a change in yaw. The model builds on previous work where the turbines define the nodes of the graph and the edges represent the interactions between turbines. Advances associated with the dynamic yaw model include a novel analytical description of the deformation of wind turbine wakes under yaw to represent the velocity deficits and a more accurate representation of the interturbine travel time of wakes. The accuracy of the model is improved by coupling it with time‐ and space‐dependent estimates of the wind farm inflow based on real‐time data from the wind farm. The model is validated both statically and dynamically using large‐eddy simulations. An application of the model is presented that incorporates the model into an optimal control loop to control the farm power output.
Journal Article
Trial of Three Rounds of Mass Azithromycin Administration for Yaws Eradication
by
Vall-Mayans, Martí
,
Maika, Edward
,
Mooring, Eric Q
in
Adolescent
,
Anti-Bacterial Agents - administration & dosage
,
Antibiotics
2022
Treponema pallidum
subspecies
pertenue
causes yaws. In this cluster-randomized, community-based trial in Papua New Guinea, the reduction in the prevalence of yaws was greater with three rounds of mass administration of azithromycin than with a single round of mass administration of azithromycin followed by targeted treatment.
Journal Article
Multiplex Mediator Displacement Loop-Mediated Isothermal Amplification for Detection of Treponema pallidum and Haemophilus ducreyi
by
Asiedu, Kingsley
,
Adu-Sarkodie, Yaw
,
Knauf, Sascha
in
Bacterial infections
,
Chancroid - diagnosis
,
Chancroid - microbiology
2020
Yaws, a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue, manifests as ulcerative skin lesions. Nucleic acid amplification tests, like loop-mediated isothermal amplification (LAMP), are versatile tools to distinguish yaws from infections that cause similar skin lesions, primarily Haemophilus ducreyi. We developed a novel molecular test to simultaneously detect T. pallidum and H. ducreyi based on mediator displacement LAMP. We validated the T. pallidum and H. ducreyi LAMP (TPHD-LAMP) by testing 293 clinical samples from patients with yaws-like lesions. Compared with quantitative PCR, the TPHD-LAMP demonstrated high sensitivity and specificity for T. pallidum (84.7% sensitivity, 95.7% specificity) and H. ducreyi (91.6% sensitivity, 84.8% specificity). This novel assay provided rapid molecular confirmation of T. pallidum and H. ducreyi DNA and might be suitable for use at the point of care. TPHD-LAMP could support yaws eradication by improving access to molecular diagnostic tests at the district hospital level.
Journal Article
Integrated approach in the control and management of skin neglected tropical diseases in three health districts of Côte d’Ivoire
2020
Background
Neglected tropical diseases (NTDs) comprise 20 communicable diseases that are prevalent in rural poor and remote communities with less access to the health system. For effective and efficient control, the WHO recommends that affected countries implement integrated control interventions that take into account the different co-endemic NTDs in the same community. However, implementing these integrated interventions involving several diseases with different etiologies, requiring different control approaches and driven by different vertical programs, remains a challenge. We report here the results and lessons learned from a pilot test of this integrated approach based on integrated screening of skin diseases in three co-endemic health districts of Côte d’Ivoire, a West African country endemic for Buruli ulcer, leprosy and yaw.
Method
This cross-sectional study took place from April 2016 to March 2017 in 3 districts of Côte d’Ivoire co-endemic for BU, leprosy and yaws. The study was carried out in 6 stages: identification of potentially co-endemic communities; stakeholder training; social mobilization; mobile medical consultations; case detection and management; and a review meeting.
Results
We included in the study all patients with skin signs and symptoms at the screening stage who voluntarily accepted screening.
In total, 2310 persons screened had skin lesions at the screening stage. Among them, 07 cases were diagnosed with Buruli ulcer. There were 30 leprosy cases and 15 yaws detected. Other types of ulcerations and skin conditions have been identified and represent the majority of cases detected. We learned from this pilot experience that integration can be successfully implemented in co-endemic communities in Côte d’Ivoire. Health workers are motivated and available to implement integrated interventions instead of interventions focused on a single disease. However, it is essential to provide capacity building, a minimum of drugs and consumables for the care of the patients identified, as well as follow-up of identified patients, including those with other skin conditions.
Conclusions
The results of this study show that the integration of activities can be successfully implemented in co-endemic communities under the condition of staff capacity building and minimal care of identified patients.
Journal Article
Whole-genome sequencing reveals evidence for inter-species transmission of the yaws bacterium among nonhuman primates in Tanzania
2025
Treponema pallidum subspecies pertenue (TPE) is the causative agent of human and nonhuman primate (NHP) yaws infection. The discovery of yaws bacterium in wild populations of NHPs opened the question of transmission mechanisms within NHPs, and this work aims to take a closer look at the transmission of the disease.
Our study determined eleven whole TPE genomes from NHP isolates collected from three national parks in Tanzania: Lake Manyara National Park (NP), Serengeti NP, and Ruaha NP. The bacteria were isolated from four species of NHPs: Chlorocebus pygerythrus (vervet monkey), Cercopithecus mitis (blue monkey), Papio anubis (olive baboon), and Papio cynocephalus (yellow baboon). Combined with previously generated genomes of TPE originating from NHPs in Tanzania (n = 11), 22 whole-genome TPE sequences have now been analyzed. Out of 231 possible combinations of genome-to-genome comparisons, five revealed an unexpectedly high degree of genetic similarity in samples collected from different NHP species, consistent with inter-species transmission of TPE among NHPs. We estimated a substitution rate of TPE of NHP origin, ranging between 1.77 × 10-7 and 3.43 × 10-7 per genomic site per year.
The model estimations predicted that the inter-species transmission happened recently, within decades, roughly in an order of magnitude shorter time compared to time needed for the natural diversification of all tested TPE of Tanzanian NHP origin. Moreover, the geographical separation of the sampling sites (NPs) does not preclude TPE transmission between and within NHP species.
Journal Article
Re-emergence of yaws after single mass azithromycin treatment followed by targeted treatment: a longitudinal study
by
González-Beiras, Camila
,
Barry, Alyssa E
,
Lukehart, Sheila A
in
Adolescent
,
Anti-Bacterial Agents - therapeutic use
,
Antibiotics
2018
Yaws is a substantial cause of chronic disfiguring ulcers in children in at least 14 countries in the tropics. WHO's newly adopted strategy for yaws eradication uses a single round of mass azithromycin treatment followed by targeted treatment programmes, and data from pilot studies have shown a short-term significant reduction of yaws. We assessed the long-term efficacy of the WHO strategy for yaws eradication.
Between April 15, 2013, and Oct 24, 2016, we did a longitudinal study on a Papua New Guinea island (Lihir; 16 092 population) in which yaws was endemic. In the initial study, the participants were followed for 12 months; in this extended follow-up study, clinical, serological, and PCR surveys were continued every 6 months for 42 months. We used genotyping and travel history to identify importation events. Active yaws confirmed by PCR specific for Treponema pallidum was the primary outcome indicator. The study is registered with ClinicalTrials.gov, number NCT01955252.
Mass azithromycin treatment (coverage rate of 84%) followed by targeted treatment programmes reduced the prevalence of active yaws from 1·8% to a minimum of 0·1% at 18 months (difference from baseline −1·7%, 95% CI, −1·9 to −1·4; p<0·0001), but the infection began to re-emerge after 24 months with a significant increase to 0·4% at 42 months (difference from 18 months 0·3%, 95% CI 0·1 to 0·4; p<0·0001). At each timepoint after baseline, more than 70% of the total community burden of yaws was found in individuals who had not had the mass treatment or as new infections in non-travelling residents. At months 36 and 42, five cases of active yaws, all from the same village, showed clinical failure following azithromycin treatment, with PCR-detected mutations in the 23S ribosomal RNA genes conferring resistance to azithromycin. A sustained decrease in the prevalence of high-titre latent yaws from 13·7% to <1·5% in asymptomatic children aged 1–5 years old and of genetic diversity of yaws strains from 0·139 to less than 0·046 between months 24 and 42 indicated a reduction in transmission of infection.
The implementation of the WHO strategy did not, in the long-term, achieve elimination in a high-endemic community mainly due to the individuals who were absent at the time of mass treatment in whom yaws reactivated; repeated mass treatment might be necessary to eliminate yaws. To our knowledge, this is the first report of the emergence of azithromycin-resistant T p pertenue and spread within one village. Communities' surveillance should be strengthened to detect any possible treatment failure and biological markers of resistance.
ISDIN laboratories, Newcrest Mining Limited, and US Public Health Service National Institutes of Health.
Journal Article
Review of control strategy of large horizontal‐axis wind turbines yaw system
by
Huang, Lingxiang
,
Yang, Jian
,
Joo, Young Hoon
in
Algorithms
,
Control algorithms
,
Control methods
2021
In order to meet the increasing demand of wind energy utilization, wind turbines (WTs) are developing toward the trend of large size and large capacity. In such a trend, various advanced yaw control strategies have been proposed to improve large WTs' comprehensive performance, but the analysis and summary of these strategies are still lacking. Therefore, it is necessary to have a review of yaw control, which not only enables readers to understand the current status of yaw control research but also promotes the development of wind energy technology. This paper presents a review of the current situation of yaw control for WTs, focusing on the mechanical/aerodynamic parts. The mechanical part is concerned with the WT yaw system and its effect on the fatigue load of the WT, and the aerodynamic part involves the wind energy capture and wake redirection to reduce the impact on adjacent WTs. In this review, the existing yaw control methods are classified in term of three control objectives: (1) increasing the wind energy capture of a single WT, (2) reducing the fatigue load of a single WT, and (3) maximizing the total power production of the whole wind farm and optimizing the wind farm fatigue load. On this basis, the control mechanism, the control algorithm, and the results are presented and analyzed in detail. Meanwhile, the advantages and disadvantages of the existing achievements are discussed. In addition, in a conclusion of the review, the future research direction has been identified.
Journal Article
A New Analytical Wake Model for Yawed Wind Turbines
by
Qian, Guo-Wei
,
Ishihara, Takeshi
in
added turbulence intensity
,
ambient turbulence
,
Boundary layer
2018
A new analytical wake model for wind turbines, considering ambient turbulence intensity, thrust coefficient and yaw angle effects, is proposed from numerical and analytical studies. First, eight simulations by the Reynolds Stress Model are conducted for different thrust coefficients, yaw angles and ambient turbulence intensities. The wake deflection, mean velocity and turbulence intensity in the wakes are systematically investigated. A new wake deflection model is then proposed to analytically predict the wake center trajectory in the yawed condition. Finally, the effects of yaw angle are incorporated in the Gaussian-based wake model. The wake deflection, velocity deficit and added turbulence intensity in the wake predicted by the proposed model show good agreement with the numerical results. The model parameters are determined as the function of ambient turbulence intensity and thrust coefficient, which enables the model to have good applicability under various conditions.
Journal Article