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.

Gender differences in the surgical management of trachomatous trichiasis: an exploratory analysis of global trachoma survey data, 2015-2019.

BACKGROUND: Trachomatous trichiasis (TT) is a painful, potentially blinding eye condition that can be managed through epilation or surgery. Women are affected by TT approximately twice as often as men and are believed to face gendered barriers to receiving surgical care to prevent vision loss. METHODS: We used data from 817 cross-sectional surveys conducted during 2015-2019 in 20 African countries to estimate the prevalence difference (PD) between female and male eyes for four outcomes potentially indicating gender-related differences in TT management: (1) received surgery and developed postoperative TT (PTT), (2) never offered surgery, (3) offered surgery but declined it, and (4) offered epilation but never offered surgery. RESULTS: The prevalence was modestly elevated among female eyes compared with male eyes for having PTT (PD:1.8 [95% confidence limits (CL): 0.6, 3.0]) and having declined surgery for the eye (PD: 6.2 [95% CL: 1.8, 10.7]). The proportion offered epilation was similar by gender (PD:0.5 [95% CL: -0.4, 1.3]), while never having been offered surgery was somewhat more prevalent among male eyes (PD: -2.1 [95% CL: -3.5, -0.7]). CONCLUSIONS: Our results suggest potential gender differences in TT management. More research is needed to determine the causes and implications of the observed differences.

Changes in trachoma indicators in Kiribati with two rounds of azithromycin mass drug administration, measured in serial population-based surveys.

Baseline mapping in the two major population centers of Kiribati showed that trachoma was a public health problem in need of programmatic interventions. After conducting two annual rounds of antibiotic mass drug administration (MDA), Kiribati undertook trachoma impact surveys in 2019, using standardized two-stage cluster surveys in the evaluation units of Kiritimati Island and Tarawa. In Kiritimati, 516 households were visited and in Tarawa, 772 households were visited. Nearly all households had a drinking water source and access to an improved latrine. The prevalence of trachomatous trichiasis remained above the elimination threshold (0.2% in ≥15-year-olds) and was virtually unchanged from baseline. The prevalence of trachomatous inflammation-follicular (TF) in 1-9-year-olds decreased by approximately 40% from baseline in both evaluation units but remained above the 5% TF prevalence threshold for stopping MDA. TF prevalence at impact survey was 11.5% in Kiritimati and 17.9% in Tarawa. Infection prevalence in 1-9-year-olds by PCR was 0.96% in Kiritimati and 3.3% in Tarawa. Using a multiplex bead assay to measure antibodies to the C. trachomatis antigen Pgp3, seroprevalence in 1-9-year-olds was 30.2% in Kiritimati and 31.4% in Tarawa. The seroconversion rate, in seroconversion events/100 children/year, was 9.0 in Kiritimati and 9.2 in Tarawa. Seroprevalence and seroconversion rates were both assessed by four different assays, with strong agreement between tests. These results show that, despite decreases in indicators associated with infection at impact survey, trachoma remains a public health problem in Kiribati, and provide additional information about changes in serological indicators after MDA.

Patient Perspectives of Diabetes and Diabetic Retinopathy Services in Kiribati: A Qualitative Study.

Diabetes mellitus is an increasing global health problem affecting millions of people worldwide, especially true in the Republic of Kiribati, with >20% of adults suffering from type 2 diabetes, and the prevalence is rising. Information on I-Kiribati patients' understanding of diabetes and perception of access to relevant services is sparse. This study explores patient perspectives on their condition and its management using Talanga and Kakala Pacific research methodologies. Data were collected from Kiribati patients in four focus group interviews. Key themes to emerge were knowledge about diabetes, understanding and accessing the health care system, making lifestyle changes, and suggestions for improvement. Health system failures to meet the complex health care needs of these patients and health care services gaps are apparent. Improvements suggested include a comprehensive village-based health promotion and community development program focusing on youth and schools from early childhood and onward, increase in the skilled workforce, and an integrated approach to service delivery.

The simplified trachoma grading system, amended.

A simplified grading system for trachoma was published by the World Health Organization (WHO) in 1987. Intended for use by non-specialist personnel working at community level, the system includes five signs, each of which can be present or absent in any eye: (i) trachomatous trichiasis; (ii) corneal opacity; (iii) trachomatous inflammation-follicular; (iv) trachomatous inflammation-intense; and (v) trachomatous scarring. Though neither perfectly sensitive nor perfectly specific for trachoma, these signs have been essential tools for identifying populations that need interventions to eliminate trachoma as a public health problem. In 2018, at WHO's 4th global scientific meeting on trachoma, the definition of one of the signs, trachomatous trichiasis, was amended to exclude trichiasis that affects only the lower eyelid. This paper presents the amended system, updates its presentation, offers notes on its use and identifies areas of ongoing debate.

En 1987, l'Organisation mondiale de la Santé a publié un système de codage simplifié du trachome. Destiné au personnel non qualifié travaillant au sein des communautés, il comporte cinq signes, chacun pouvant être présent ou absent dans l'un ou l'autre œil: (i) le trichiasis trachomateux; (ii) l'opacité cornéenne; (iii) l'inflammation trachomateuse ­ folliculaire; (iv) l'inflammation trachomateuse ­ intense; et enfin, (v) la cicatrice trachomateuse. Bien qu'ils ne soient ni parfaitement précis, ni totalement spécifiques au trachome, ces signes constituent des outils essentiels pour identifier les populations qui nécessitent une intervention afin d'éliminer le trachome en tant que problème de santé publique. En 2018, lors de la quatrième réunion scientifique mondiale sur le trachome, la définition de l'un des signes, le trichiasis trachomateux, a été modifiée pour exclure du système de codage le trichiasis qui n'affecte que la paupière inférieure. Ce document expose le nouveau système, actualise sa présentation, formule des remarques sur son utilisation et identifie les domaines qui font encore l'objet de débats.

En 1987, la Organización Mundial de la Salud (OMS) publicó un sistema de clasificación simplificado para el tracoma. Este sistema fue diseñado para que lo utilice el personal no especializado que trabaja a nivel comunitario e incluye cinco signos, cada uno de los cuales puede estar presente o ausente en los ojos: i) la triquiasis tracomatosa; ii) la opacidad corneal; iii) la inflamación tracomatosa-folicular; iv) la inflamación tracomatosa-intensa; y v) la cicatrización tracomatosa. Si bien no son perfectamente sensibles ni muy específicos del tracoma, estos signos han sido herramientas esenciales para identificar a las poblaciones que requieren intervenciones para eliminar el tracoma como problema de salud pública. En 2018, se modificó la definición de uno de los signos, la triquiasis tracomatosa, en la 4.ª Reunión Científica Mundial sobre el Tracoma de la OMS, para descartar la triquiasis que solo afecta al párpado inferior. En el presente documento se describe el sistema modificado, se actualiza su presentación, se ofrecen observaciones sobre su aplicación y se identifican los ámbitos de debate en curso.

Ocular Chlamydia trachomatis infection, anti-Pgp3 antibodies and conjunctival scarring in Vanuatu and Tarawa, Kiribati before antibiotic treatment for trachoma.

INTRODUCTION: In the peri-elimination setting, the positive predictive value of trachomatous inflammation-follicular (TF), the primary marker used to determine need for antibiotics for trachoma, is suboptimal. Here, three non-TF measures are used to compare two regions where TF prevalence exceeds the threshold for intervention, but where the Chlamydia trachomatis (Ct) prevalence is different. METHODS: Population prevalence of trachoma was measured in Vanuatu (n = 3470) and Kiribati (n = 2922). Dried blood spots (DBS) and conjunctival photographs were collected from every survey participant, and conjunctival swabs were collected from those aged 1-9 years. Individuals were tested for blood anti-Pgp3 antibodies, Ct DNA at the conjunctiva and severity of conjunctival scarring. RESULTS: The prevalence of TF in 1-9-year-olds was 16.5% in Vanuatu and 38.2% in Tarawa. 7% of people aged ≥1 year in Vanuatu had conjunctival scarring compared to 27% in Tarawa. The prevalence of ocular Ct infection in 1-9-year-olds was 1.5% in Vanuatu and 27.4% in Tarawa. The seroconversion rate amongst 1-9-year-old children in Vanuatu and Tarawa was 0.018 and 0.197 events per child per year, respectively. CONCLUSIONS: Comparing Vanuatu to Tarawa demonstrates several markers that could be used to differentiate the trachoma status of populations in these (and other) locations.

Absence of Serological Evidence of Exposure to Treponema pallidum among Children Suggests Yaws Is No Longer Endemic in Kiribati.

Yaws is a neglected tropical disease targeted for eradication by 2020. Kiribati, a Pacific Island nation, was previously endemic for yaws but lacks recent data from which its current endemicity status could be determined. This study tested antibody responses to Treponema pallidum to determine if transmission of yaws is taking place among children in Kiribati. Using a commercially available T. pallidum particle agglutination kit (Serodia®, Fujirebio Inc., Tokyo, Japan), we tested dried blood spots, collected during population-based trachoma prevalence surveys on Tarawa Atoll and Kiritimati Island, for long-lived treponemal antibodies. Dried blood spots from 1,420 children aged 1-9 years were tested. Only two were positive, suggesting T. pallidum is not being widely transmitted among children in the settings sampled. These data require support from additional surveys to demonstrate the absence of clinical signs of disease and molecular evidence of infection, to confirm that yaws is no longer endemic in Kiribati.

The utility of serology for elimination surveillance of trachoma.

Robust surveillance methods are needed for trachoma control and recrudescence monitoring, but existing methods have limitations. Here, we analyse data from nine trachoma-endemic populations and provide operational thresholds for interpretation of serological data in low-transmission and post-elimination settings. Analyses with sero-catalytic and antibody acquisition models provide insights into transmission history within each population. To accurately estimate sero-conversion rates (SCR) for trachoma in populations with high-seroprevalence in adults, the model accounts for secondary exposure to Chlamydia trachomatis due to urogenital infection. We estimate the population half-life of sero-reversion for anti-Pgp3 antibodies to be 26 (95% credible interval (CrI): 21-34) years. We show SCRs below 0.015 (95% confidence interval (CI): 0.0-0.049) per year correspond to a prevalence of trachomatous inflammation-follicular below 5%, the current threshold for elimination of active trachoma as a public health problem. As global trachoma prevalence declines, we may need cross-sectional serological survey data to inform programmatic decisions.

Prevalence of signs of trachoma, ocular Chlamydia trachomatis infection and antibodies to Pgp3 in residents of Kiritimati Island, Kiribati.

OBJECTIVE: In some Pacific Island countries, such as Solomon Islands and Fiji, active trachoma is common, but ocular Chlamydia trachomatis (Ct) infection and trachomatous trichiasis (TT) are rare. On Tarawa, the most populous Kiribati island, both the active trachoma sign "trachomatous inflammation-follicular" (TF) and TT are present at prevalences warranting intervention. We sought to estimate prevalences of TF, TT, ocular Ct infection, and anti-Ct antibodies on Kiritimati Island, Kiribati, to assess local relationships between these parameters, and to help determine the need for interventions against trachoma on Kiribati islands other than Tarawa. METHODS: As part of the Global Trachoma Mapping Project (GTMP), on Kiritimati, we examined 406 children aged 1-9 years for active trachoma. We collected conjunctival swabs (for droplet digital PCR against Ct plasmid targets) from 1-9-year-olds with active trachoma, and a systematic selection of 1-9-year-olds without active trachoma. We collected dried blood spots (for anti-Pgp3 ELISA) from all 1-9-year-old children. We also examined 416 adults aged ≥15 years for TT. Prevalence of TF and TT was adjusted for age (TF) or age and gender (TT) in five-year age bands. RESULTS: The age-adjusted prevalence of TF in 1-9-year-olds was 28% (95% confidence interval [CI]: 24-35). The age- and gender-adjusted prevalence of TT in those aged ≥15 years was 0.2% (95% CI: 0.1-0.3%). Twenty-six (13.5%) of 193 swabs from children without active trachoma, and 58 (49.2%) of 118 swabs from children with active trachoma were positive for Ct DNA. Two hundred and ten (53%) of 397 children had anti-Pgp3 antibodies. Both infection (p<0.0001) and seropositivity (p<0.0001) were strongly associated with active trachoma. In 1-9-year-olds, the prevalence of anti-Pgp3 antibodies rose steeply with age. CONCLUSION: Trachoma presents a public health problem on Kiritimati, where the high prevalence of ocular Ct infection and rapid increase in seropositivity with age suggest intense Ct transmission amongst young children. Interventions are required here to prevent future blindness.