Comparison of two approaches to measuring clean faces as part of the facial cleanliness component of the SAFE trachoma elimination strategy.

BACKGROUND: The Alliance for the Global Elimination of Trachoma (GET) endorses the full SAFE strategy to eliminate trachoma; Surgery (for trichiasis), Antibiotics (to reduce the community pool of infection, Facial cleanliness, and Environmental improvement (to decrease transmission). There is no accepted measure of facial cleanliness. This study compared two possible metrics for facial cleanliness. METHOD/FINDINGS: Metric one: Clean face was defined as observed absence of ocular and nasal discharge on the face. Metric two: observing a grade of dirtiness (scale 10 = lightest to 0 = darkest) on a standard facial wipe. The reliability of grading a child's face or grading a facial wipe was determined in children in Kongwa Tanzania. We also observed both measurements in a cohort of 202 children ages 1 to <7years prior to face cleaning, immediately afterwards, and 4 hours afterwards. Fifty of the children did not have face cleaning and were controls. Intra-and interobserver reliability was similar for both measures, the latter = 0.53 for observing a clean face and 0.52 for grading a facial wipe. There was no correlation between the two. Both measures detected facial cleaning, compared to control children who were not cleaned, immediately after cleaning; control children with 53% clean faces and wipe score of 6.7 compared to cleaned children with 88% clean faces and wipe score of 8 (p = .0001, p = < .0001, respectively). Both measures also detected face washing 4 hours previously compared to controls. CONCLUSIONS: The two metrics were equally reliable, and both measured the behavior of face washing. They measure different aspects of a clean face; one measures the amount of dirt on wiped area and the other measures ocular and nasal discharge. Both measurements appear to capture the behavior of facial cleaning, and the choice of metric would appear to rest on the measurement that captures the stated objective of the behavior, consideration of costs, training, logistics, and implementation.

District-Level Forecast of Achieving Trachoma Elimination as a Public Health Problem By 2030: An Ensemble Modelling Approach.

Assessing the feasibility of 2030 as a target date for global elimination of trachoma, and identification of districts that may require enhanced treatment to meet World Health Organization (WHO) elimination criteria by this date are key challenges in operational planning for trachoma programmes. Here we address these challenges by prospectively evaluating forecasting models of trachomatous inflammation-follicular (TF) prevalence, leveraging ensemble-based approaches. Seven candidate probabilistic models were developed to forecast district-wise TF prevalence in 11 760 districts, trained using district-level data on the population prevalence of TF in children aged 1-9 years from 2004 to 2022. Geographical location, history of mass drug administration treatment, and previously measured prevalence data were included in these models as key predictors. The best-performing models were included in an ensemble, using weights derived from their relative likelihood scores. To incorporate the inherent stochasticity of disease transmission and challenges of population-level surveillance, we forecasted probability distributions for the TF prevalence in each geographic district, rather than predicting a single value. Based on our probabilistic forecasts, 1.46% (95% confidence interval [CI]: 1.43-1.48%) of all districts in trachoma-endemic countries, equivalent to 172 districts, will exceed the 5% TF control threshold in 2030 with the current interventions. Global elimination of trachoma as a public health problem by 2030 may require enhanced intervention and/or surveillance of high-risk districts.

Unravelling Chlamydia trachomatis diversity in Amhara, Ethiopia: MLVA-ompA sequencing as a molecular typing tool for trachoma.

Trachoma is the leading infectious cause of blindness worldwide and is now largely confined to around 40 low- and middle-income countries. It is caused by Chlamydia trachomatis (Ct), a contagious intracellular bacterium. The World Health Organization recommends mass drug administration (MDA) with azithromycin for treatment and control of ocular Ct infections, alongside improving facial cleanliness and environmental conditions to reduce transmission. To understand the molecular epidemiology of trachoma, especially in the context of MDA and transmission dynamics, the identification of Ct genotypes could be useful. While many studies have used the Ct major outer membrane protein gene (ompA) for genotyping, it has limitations. Our study applies a typing system novel to trachoma, Multiple Loci Variable Number Tandem Repeat Analysis combined with ompA (MLVA-ompA). Ocular swabs were collected post-MDA from four trachoma-endemic zones in Ethiopia between 2011-2017. DNA from 300 children with high Ct polymerase chain reaction (PCR) loads was typed using MLVA-ompA, utilizing 3 variable number tandem repeat (VNTR) loci within the Ct genome. Results show that MLVA-ompA exhibited high discriminatory power (0.981) surpassing the recommended threshold for epidemiological studies. We identified 87 MLVA-ompA variants across 26 districts. No significant associations were found between variants and clinical signs or chlamydial load. Notably, overall Ct diversity significantly decreased after additional MDA rounds, with a higher proportion of serovar A post-MDA. Despite challenges in sequencing one VNTR locus (CT1299), MLVA-ompA demonstrated cost-effectiveness and efficiency relative to whole genome sequencing, providing valuable information for trachoma control programs on local epidemiology. The findings suggest the potential of MLVA-ompA as a reliable tool for typing ocular Ct and understanding transmission dynamics, aiding in the development of targeted interventions for trachoma control.

Prevalence of trachoma in indigenous and non-indigenous areas, Northeastern Brazil, 2019–2021 / Prevalencia del tracoma en zonas de población indígena y no indígena del nordeste de Brasil, 2019-2021 / Prevalência de tracoma em áreas indígenas e não indígenas, Nordeste do Brasil, 2019-2021

[ABSTRACT]. Objective. To estimate the prevalence of trachoma in indigenous and non-indigenous populations in selected areas of the state of Maranhão, in northeastern Brazil. Methods. This was a population-based survey with probabilistic sampling. For the diagnosis of trachoma, external ocular examination was performed using head magnifying loupes, at 2.5X magnification. The prevalence of trachomatous inflammation – follicular (TF) in children aged 1–9 years and the prevalence of trachomatous trichiasis (TT) in the population aged ≥15 years were estimated. Relative frequencies of sociodemographic and environmental characteristics were obtained. Results. The study included 7 971 individuals, 3 429 from non-indigenous populations and 4 542 from indigenous populations. The prevalence of TF in non-indigenous and indigenous populations was 0.1% and 2.9%, respectively, and the prevalence of TT among indigenous populations was 0.1%. Conclusions. The prevalence of TF and TT in the two evaluation units in the state of Maranhão were within the limits recommended for the elimination of trachoma as a public health problem. However, the prevalence of TF was higher in the indigenous evaluation unit, indicating a greater vulnerability of this population to the disease. The prevalence of TF of below 5.0% implies a reduction in transmission, which may have resulted from improved socioeconomic conditions and/or the implementation of the World Health Organization SAFE strategy.

[RESUMEN]. Objetivo. Estimar la prevalencia del tracoma en poblaciones indígenas y no indígenas en determinadas zonas del estado de Maranhão, en el nordeste de Brasil. Métodos. Se trató de una encuesta de ámbito poblacional con muestreo probabilístico. Para el diagnóstico del tracoma, se realizó un examen ocular externo con una lupa frontal de 2,5X aumentos. Se estimó la prevalencia de la inflamación tracomatosa folicular (TF) en la población infantil de 1 a 9 años y la prevalencia de la triquiasis tracomatosa (TT) en la población de 15 años o más. Se obtuvieron las frecuencias relativas de las características sociodemográficas y ambientales. Resultados. En el estudio participaron 7 971 personas, 3 429 de poblaciones no indígenas y 4 542 de poblaciones indígenas. La prevalencia de la TF en las poblaciones no indígenas e indígenas fue de 0,1% y 2,9%, respectivamente, en tanto que la de la TT en las poblaciones indígenas fue de 0,1%. Conclusiones. La prevalencia de la TF y la TT en las dos unidades de evaluación del estado de Maranhão estuvo dentro de los límites recomendados para la eliminación del tracoma como problema de salud pública. Sin embargo, la prevalencia de la TF fue mayor en la unidad de evaluación indígena, lo que indica una mayor vulnerabilidad de esta población a la enfermedad. La prevalencia de la TF inferior al 5,0% implica una reducción de la transmisión, que puede haber sido consecuencia tanto de la mejora de las condiciones socioeconómicas como de la aplicación de la estrategia SAFE de la Organización Mundial de la Salud.

[RESUMO]. Objetivo. Estimar a prevalência do tracoma em populações indígenas e não indígenas em áreas selecionadas do estado do Maranhão, na região Nordeste do Brasil. Métodos. Inquérito de base populacional com amostragem probabilística. Para o diagnóstico de tracoma, foi realizado exame ocular externo com o auxílio de lupas binoculares com ampliação de 2,5×. Foram estimadas a prevalência de inflamação tracomatosa folicular (TF) em crianças de 1 a 9 anos de idade e a prevalência de triquíase tracomatosa (TT) na população com idade ≥15 anos. Foram obtidas as frequências relativas das características sociodemográficas e ambientais. Resultados. O estudo incluiu 7 971 indivíduos (3 429 de populações não indígenas e 4 542 de populações indígenas). A prevalência de TF nas populações não indígenas e indígenas foi de 0,1% e 2,9%, respectiva- mente, e a prevalência de TT entre as populações indígenas foi de 0,1%. Conclusões. A prevalência de TF e TT nas duas unidades de avaliação no estado do Maranhão ficou dentro dos limites recomendados para a eliminação do tracoma como problema de saúde pública. No entanto, a prevalência de TF foi maior na unidade de avaliação indígena, indicando uma maior vulnerabilidade dessa população à doença. A prevalência de TF abaixo de 5,0% implica uma redução na transmissão, que pode ter sido resultado de melhores condições socioeconômicas e da implementação da estratégia SAFE da Organização Mundial da Saúde.

Efficacy of Single-Dose Azithromycin for Ocular Chlamydial Infection: A Longitudinal Study.

Millions of doses of azithromycin are distributed each year for trachoma, yet the treatment efficacy of a single dose of azithromycin for ocular Chlamydia infection has not been well characterized. In this study, four villages in Niger received a mass azithromycin distribution for trachoma. All 426 children aged 0-5 years residing in the study villages were offered conjunctival swabbing every 6 months to test for ocular Chlamydia trachomatis. Among the children infected with ocular Chlamydia before treatment, 6% (95% CI: 2-15%) tested positive for ocular Chlamydia infection 6 months later, and 15% (95% CI: 7-28%) tested positive 12 months later. The most important predictor of post-treatment ocular Chlamydia infection was pretreatment ocular Chlamydia infection (relative risk: 3.5, 95% CI: 1.3-9.4). Although the 6-monthly monitoring schedule was suboptimal for testing the treatment efficacy of an antibiotic, these findings are nonetheless consistent with high treatment efficacy of a single dose of azithromycin and suggest that additional interventions might be most effective if targeted to those children infected prior to treatment.

Genomic insights into local-scale evolution of ocular Chlamydia trachomatis strains within and between individuals in Gambian trachoma-endemic villages.

Trachoma, a neglected tropical disease caused by Chlamydia trachomatis (Ct) serovars A-C, is the leading infectious cause of blindness worldwide. Africa bears the highest burden, accounting for over 86 % of global trachoma cases. We investigated Ct serovar A (SvA) and B (SvB) whole genome sequences prior to the induction of mass antibiotic drug administration in The Gambia. Here, we explore the factors contributing to Ct strain diversification and the implications for Ct evolution within the context of ocular infection. A cohort study in 2002-2003 collected ocular swabs across nine Gambian villages during a 6 month follow-up study. To explore the genetic diversity of Ct within and between individuals, we conducted whole-genome sequencing (WGS) on a limited number (n=43) of Ct-positive samples with an omcB load ≥10 from four villages. WGS was performed using target enrichment with SureSelect and Illumina paired-end sequencing. Out of 43 WGS samples, 41 provided sufficient quality for further analysis. ompA analysis revealed that 11 samples had highest identity to ompA from strain A/HAR13 (NC_007429) and 30 had highest identity to ompA from strain B/Jali20 (NC_012686). While SvB genome sequences formed two distinct village-driven subclades, the heterogeneity of SvA sequences led to the formation of many individual branches within the Gambian SvA subclade. Comparing the Gambian SvA and SvB sequences with their reference strains, Ct A/HAR13 and Ct B/Jali20, indicated an single nucleotide polymorphism accumulation rate of 2.4×10-5 per site per year for the Gambian SvA and 1.3×10-5 per site per year for SvB variants (P<0.0001). Variant calling resulted in a total of 1371 single nucleotide variants (SNVs) with a frequency >25 % in SvA sequences, and 438 SNVs in SvB sequences. Of note, in SvA variants, highest evolutionary pressure was recorded on genes responsible for host cell modulation and intracellular survival mechanisms, whereas in SvB variants this pressure was mainly on genes essential for DNA replication/repair mechanisms and protein synthesis. A comparison of the sequences between observed separate infection events (4-20 weeks between infections) suggested that the majority of the variations accumulated in genes responsible for host-pathogen interaction such as CTA_0166 (phospholipase D-like protein), CTA_0498 (TarP) and CTA_0948 (deubiquitinase). This comparison of Ct SvA and SvB variants within a trachoma endemic population focused on their local evolutionary adaptation. We found a different variation accumulation pattern in the Gambian SvA chromosomal genes compared with SvB, hinting at the potential of Ct serovar-specific variation in diversification and evolutionary fitness. These findings may have implications for optimizing trachoma control and prevention strategies.

Wait and watch: A trachoma surveillance strategy from Amhara region, Ethiopia.

BACKGROUND: Trachoma recrudescence after elimination as a public health problem has been reached is a concern for control programs globally. Programs typically conduct district-level trachoma surveillance surveys (TSS) ≥ 2 years after the elimination threshold is achieved to determine whether the prevalence of trachomatous inflammation-follicular (TF) among children ages 1 to 9 years remains <5%. Many TSS are resulting in a TF prevalence ≥5%. Once a district returns to TF ≥5%, a program typically restarts costly mass drug administration (MDA) campaigns and surveys at least twice, for impact and another TSS. In Amhara, Ethiopia, most TSS which result in a TF ≥5% have a prevalence close to 5%, making it difficult to determine whether the result is due to true recrudescence or to statistical variability. This study's aim was to monitor recrudescence within Amhara by waiting to restart MDA within 2 districts with a TF prevalence ≥5% at TSS, Metema = 5.2% and Woreta Town = 5.1%. The districts were resurveyed 1 year later using traditional and alternative indicators, such as measures of infection and serology, a "wait and watch" approach. METHODS/PRINCIPAL FINDINGS: These post-surveillance surveys, conducted in 2021, were multi-stage cluster surveys whereby certified graders assessed trachoma signs. Children ages 1 to 9 years provided a dried blood spot and children ages 1 to 5 years provided a conjunctival swab. TF prevalence in Metema and Woreta Town were 3.6% (95% Confidence Interval [CI]:1.4-6.4) and 2.5% (95% CI:0.8-4.5) respectively. Infection prevalence was 1.2% in Woreta Town and 0% in Metema. Seroconversion rates to Pgp3 in Metema and Woreta Town were 0.4 (95% CI:0.2-0.7) seroconversions per 100 child-years and 0.9 (95% CI:0.6-1.5) respectively. CONCLUSIONS/SIGNIFICANCE: Both study districts had a TF prevalence <5% with low levels of Chlamydia trachomatis infection and transmission, and thus MDA interventions are no longer warranted. The wait and watch approach represents a surveillance strategy which could lead to fewer MDA campaigns and surveys and thus cost savings with reduced antibiotic usage.

Prevalence of trachomatous inflammation-follicular and associated factors among children aged 1-9 years in northeastern Ethiopia.

BACKGROUND: Trachoma is the most prevalent eye disease in Ethiopia, especially among children aged 1-9 years and continues to be a public health concern. Nevertheless, in Ethiopia's rural Jamma district in South Wollo Zone of Amhara Regional State, factors associated with trachomatous inflammation-follicular (TF) among children aged 1-9 years have not yet been studied. METHODS: A community-based cross-sectional study was conducted among 616 children aged 1-9 years in rural Jamma district in Ethiopia from January-March, 2019. Data were collected using a pre-tested structured questionnaire, an observation checklist and clinical examination of study participants for active trachoma. The presence of TF and trachomatous inflammation-intense (TI) was clinically assessed by integrated eye care workers using the World Health Organization simplified grading system. Data were analysed using SPSS (Statistical Package for Social Sciences) Version 25.0. A logistic regression model with 95% CI was used. From the multivariable analysis, variables with p-value < 0.05 were declared as associated factors of TF. RESULT: The prevalence of TF was 10.9% (95% CI [8.6 - 13.6%]) among the rural children aged 1-9 years. The mean family size was 5.5 ± 1.9 persons. About one-fifth (20.6%) of households kept domestic animals overnight in the same room as family. Almost one-sixth (17.5%) of the children involved in this study had an ocular discharge. Two-thirds of the children (68.8%) washed their hands once per day and just over half (55.8%) washed their faces once per day. From multivariable analysis, we found that the presence of domestic animals kept overnight in the same room as the family (adjusted odds ratio [AOR] = 4.32; 95%CI [2.49-9.52]), mother's/caregiver's illiteracy (AOR = 2.01; 95%CI [1.11-4.67]), household size (> 7 persons) (AOR = 3.50; 95%CI [1.66-8.50]), washing of children's hands and face without soap (AOR = 2.41; 95%CI [1.29-5.18]), feces observed in the compound (AOR = 5.10; 95%CI [2.01-10.14]), presence of ocular discharge (AOR = 7.23, 95%CI [4.10-12.51]) and nasal discharge (AOR = 4.54, 95%CI [1.95-9.26]) were significantly associated with TF. CONCLUSION: The prevalence of TF among rural children aged 1-9 years in this study was almost two times higher than the WHO-recommended threshold (TF < 5%) for trachoma elimination and beyond the trachoma control target (TF < 10%). Presence of domestic animals kept overnight in the same room as the family, mother's/caregiver's illiteracy, household size (> 7 persons), washing of children's hands and face without soap, feces observed in the compound, presence of ocular and nasal discharge were significantly associated with TF. We recommended interventions that will help household income to be improved to enable families to be able to construct separate rooms in which to keep animals overnight. Furthermore, we also recommend to policy makers to design mechanisms for enhancement of behavioural change among householders to keep household compounds clean and creating awareness among mothers/caregivers about prevention of trachoma.

Gender differences in trachomatous scarring prevalence in a formerly trachoma hyperendemic district in Tanzania.

BACKGROUND: Trachoma is a chronic conjunctivitis caused by the bacterium Chlamydia trachomatis. Repeated infections lead to trachomatous conjunctival scarring which can progress to potentially blinding trachomatous trichiasis (TT). In trachoma hyperendemic conditions, women compared to men have an increased risk of scarring and TT, which can progress to blinding corneal opacification. This study determined if there were gender differences in scarring prevalence and severity when trachoma prevalence approaches elimination, in a formerly trachoma hyperendemic region. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional prevalence study was conducted amongst adults age 15 years and older in Kongwa district, Tanzania in 2019. 3168 persons over age 15 years agreed to be examined and had at least one eye with a gradable image. Ocular photographs were graded for scarring according to a published four-step severity scale. Overall, about half of all study participants had scarring. However, more females (52.3%) had any scarring compared to males (47.2%), OR = 1.22 (95% CI = 1.05-1.43). For every year increase in age, there was a 6.5% increase in the odds of having more severe scarring (95% CI: 5.8%, 7.2%). Women were more likely than men to have severe scarring, OR 2.36 (95% CI: 1.84-3.02). Residence in a community with TF≥10% was associated with a 1.6-fold increased odds of any scarring. CONCLUSIONS/SIGNIFICANCE: Overall scarring prevalence and more severe scarring prevalence was higher in females compared to males, even adjusting for age and community TF prevalence. The data suggest that processes occur that lead to women preferentially progressing towards more severe scarring compared to men.

Trachoma: an underdiagnosed disease revealed by a survey carried out at Jaú, São Paulo.

BACKGROUND: Trachoma is a notifiable disease in the state of São Paulo- Brazil. However, in Jaú, a municipality located in this state, in the last 10 years there are no records of cases. This study purpose is to assess if there are cases of inflammatory trachoma in schoolchildren aged 1 to 9 years in the municipality of Jaú as well if it is possible to detect clusters areas of the disease to establish elimination programs. METHODS: An epidemiological study was performed in 2018, involving a stratified random sample of schoolchildren aged 1- to 9-year-old, from public day care centers and elementary schools in the municipality of Jaú. A trachoma screening following the criteria of the World Health Organization (WHO) and the distribution of cases was assessed using geoprocessing. RESULTS: Four thousand-six hundred-nineteen children from 44 elementary schools were examined, and 126 children with active trachoma were detected, with an adjusted prevalence rate of 2.65%. The prevalence was higher (3.01%) in children aged 6- to 9-year-old compared to children aged 1-to 5-year-old (2.42%). There were clusters with a higher concentration of positive cases of the disease in three schools located in the neighborhoods with lower socioeconomic conditions. CONCLUSION: Inflammatory trachoma still present in children aged 1- to 9-year-old in the city of Jaú. The positive cases were located mainly in areas with low socioeconomic conditions. Health promotion with active search and periodical treatment must be planned to fight this important blinding cause, that persists in our municipality.

Water, Sanitation, and Hygiene (WASH) Factors Influencing the Effectiveness of Mass Drug Administration to Eliminate Trachoma as a Public Health Problem in Malawi.

PURPOSE: Following a national population-based trachoma survey in Malawi one round of azithromycin mass drug administration (MDA) was carried out, with a post-MDA impact survey showing TF prevalence below 5% and considered eliminated as a public health problem. However, active trachoma was still present in over 200 children. We assessed whether water, sanitation, and hygiene (WASH) factors were associated with ongoing presence of TF in children aged 1-9 years following MDA. METHODS: A secondary analysis was performed on a sub-set of the post-MDA impact survey data for children aged 1-9 years. We used a logistic regression analysis, adjusted for clustering at the household and village level. RESULTS: Among 16,142 children aged 1-9 years, 209 (1.3%) had TF after MDA. Factors associated with a significantly lower odds of TF after MDA were living in a household with a handwashing facility (aOR: 0.37) and living in a household where water for washing is located further away from the home (30 min away aOR: 0.39, p = .034, or more than 1 h away aOR: 0.31, p = .018) compared with water in the yard. CONCLUSION: The inverse association between a domestic handwashing facility and TF is consistent with previous findings, but the association of increasing distance to collect water for washing with a reduced risk of TF was unexpected and may reflect the impact of drought and unmeasured behavioural factors related to water usage. A more comprehensive collection of sociodemographic and WASH factor information in population-based trachoma surveys will provide insight into achieving and maintaining low levels of trachoma.

Spatial and network mapping of comorbidity with trachoma and visual-impairing NCDs in a pastoralist community in Kenya: implications for SDGs and UHC.

BACKGROUND: We explore the spatial distribution of comorbidity with trachoma and potentially visual-impairing non-communicable diseases (NCDs) and their risk factors among Kenyan pastoralists. METHODS: Using a cross-sectional study design, we recruited and clinically examined 262 study participants for NCDs (hypertension or diabetes) and trachoma using the World Health Organization grading system. Network models estimated interactions and risks linked with trachoma and NCDs while the Poisson point process determined their spatial distribution. RESULTS: Of the 262 participants, 140 (53%) had trachoma, with >71% of these cases identified among females and those >60 y of age. A total of 36 trachoma cases co-occurred with hypertension (26%) and diabetes (0.01%). NCDs were frequent among those with recurring trachoma (21%) and trachomatous trichiasis (14.3%). Trachoma and NCDs clustered together in <1 km distances (R=0.18, p=0.02). In network analysis, age was strongly associated with trachoma and NCDs. Trachoma was linked with geographic location while diabetes was linked with water source distances. Education level became the central risk factor. CONCLUSIONS: We demonstrate a twin trachoma-NCD burden that is higher among elderly pastoralists in southern Kenya. Attenuating adverse population-level visual impairment, including integrating the trachoma SAFE strategy with NCD comprehensive care, amplifies the benefits from economies of scale, accelerating realization of Sustainable Development Goal 3 and universal health coverage in hard-to-reach areas.

The prevention and management of postoperative trachomatous trichiasis: A systematic review.

Among ocular infections, trachoma is the main cause of blindness. Repeated conjunctival Chlamydia trachomatis infections lead to trichiasis, corneal opacification, and visual impairment. Surgery is often needed to relieve discomfort and preserve vision; however, a high postoperative trachomatous trichiasis (PTT) rate has been observed in various settings. We wanted to know why, whether PTT rates could be reduced, and how to manage the PTT that occurs. We performed a search of the literature. Of 217 papers screened, 59 studies were identified for inclusion as potentially relevant, the majority having been excluded for not directly concerning PTT in humans. Preventing PTT is a major challenge. Only one published trial, the STAR trial in Ethiopia, has reported a cumulative PTT rate <10% one year after surgery. The literature on the management of PTT is sparse. Though no PTT management guidelines are available, high-quality surgery with a low rate of unfavorable outcomes for PTT patients is likely to require enhanced training of a smaller group of highly-skilled surgeons. Based on the surgical complexity and the authors' own experience, the pathway for patients suffering from PTT should be studied further for improvement.

Tropical Data: Approach and Methodology as Applied to Trachoma Prevalence Surveys.

PURPOSE: Population-based prevalence surveys are essential for decision-making on interventions to achieve trachoma elimination as a public health problem. This paper outlines the methodologies of Tropical Data, which supports work to undertake those surveys. METHODS: Tropical Data is a consortium of partners that supports health ministries worldwide to conduct globally standardised prevalence surveys that conform to World Health Organization recommendations. Founding principles are health ministry ownership, partnership and collaboration, and quality assurance and quality control at every step of the survey process. Support covers survey planning, survey design, training, electronic data collection and fieldwork, and data management, analysis and dissemination. Methods are adapted to meet local context and needs. Customisations, operational research and integration of other diseases into routine trachoma surveys have also been supported. RESULTS: Between 29th February 2016 and 24th April 2023, 3373 trachoma surveys across 50 countries have been supported, resulting in 10,818,502 people being examined for trachoma. CONCLUSION: This health ministry-led, standardised approach, with support from the start to the end of the survey process, has helped all trachoma elimination stakeholders to know where interventions are needed, where interventions can be stopped, and when elimination as a public health problem has been achieved. Flexibility to meet specific country contexts, adaptation to changes in global guidance and adjustments in response to user feedback have facilitated innovation in evidence-based methodologies, and supported health ministries to strive for global disease control targets.

'Follow the cattle': a joint cross-border trachoma MDA perspective.

Trachoma, a disease caused by Chlamydia trachomatis, is the leading infectious cause of blindness. To fight it, endemic East African countries adopted the World Health Organization's SAFE Strategy, targeting surgery, antibiotics through mass drug administration (MDA), facial cleanliness and environmental improvement. Trachoma persists among nomadic communities along the Kenya-Uganda and Kenya-Tanzania borders. To address this, Kenya, Tanzania and Uganda launched synchronized MDA campaigns, simultaneously treating populations across borders. Successes included joint planning, community involvement and intergovernmental cooperation, although challenges remained in resourcing MDA cross-border focal points and in addressing coverage and funding. Novel strategies like synchronized joint cross-border MDA with community engagement are vital for sustainable trachoma elimination in these nomadic settings.