Iniciativa para la eliminación del tracoma en las Américas. Primer año de implementación: informe anual 2023-2024

El informe anual 2023-2024 de la Iniciativa para la Eliminación del Tracoma en las Américas presenta los avances más importantes en los países participantes. En la región, el tracoma sigue siendo endémico en Brasil, Colombia, Guatemala y Perú, donde afecta a unos 5,6 millones de personas, especialmente en zonas rurales y remotas, y tiene un impacto desproporcionado en mujeres y niños. Entre los principales resultados, los países endémicos han avanzado en la implementación de la Estrategia SAFE (cirugía, antibióticos, higiene facial y saneamiento ambiental, por su sigla en inglés), en cuyo caso se destacan las jornadas quirúrgicas para tratar la triquiasis tracomatosa. En México, se realizaron dos jornadas de cirugía en Chiapas, mientras que en Guatemala y otros países se capacitó al personal de salud en técnicas quirúrgicas recomendadas para tracoma. En el componente de vigilancia, Bolivia, Ecuador y El Salvador completaron sus protocolos de evaluaciones rápidas de tracoma, y en Brasil se realizó una encuesta de prevalencia de tracoma de base poblacional, que incluyó la evaluación de más de 3000 personas. Estas actividades de vigilancia se apoyaron en capacitaciones para el reconocimiento de la enfermedad, lo que permitió determinar la presencia del tracoma en diferentes áreas. Se promovieron acciones con enfoque de diversidad cultural y de género en Guatemala y Bolivia, con capacitaciones orientadas a diálogos interculturales para aumentar la aceptación de las intervenciones. El componente WASH (agua, saneamiento e higiene) fue fundamental, con un enfoque en la educación comunitaria y el desarrollo de materiales adaptados para mejorar las prácticas de higiene. Finalmente, el informe destaca los esfuerzos de comunicación y visibilidad, lo cual abarca la realización de talleres de comunicación con enfoque de género e interculturalidad, la producción de materiales promocionales y la creación de un plan de comunicaciones, que integra las acciones que se implementarán en los países y a nivel regional.

The impact of modified incision height and surgical procedure on trichiasis surgery outcomes: Results of the maximizing trichiasis surgery success (MTSS) randomized trial.

BACKGROUND: Poor surgical outcomes remain a problem in trachoma-endemic countries working to reach elimination thresholds. Methods to improve outcomes could positively impact programmatic success. METHODS: This parallel, three-armed clinical trial conducted in Ethiopia randomized individuals with previously unoperated trachomatous trichiasis (TT) to receive surgery utilizing one of three approaches: bilamellar tarsal rotation with a 3 mm incision height (BLTR-3), BLTR with 5 mm incision height (BLTR-5) and posterior lamellar tarsal rotation (PLTR). We followed participants for one year. The primary outcome was post-operative trichiasis (PTT). Secondary outcomes were eyelid contour abnormalities (ECA) and pyogenic granulomata. FINDINGS: We randomized and operated on 4,914 individuals with previously unoperated TT (6,940 eyes). Primary analyses include 6,815 eyes with follow-up. Overall, 1,149 (16.9%) eyes developed PTT. The risk difference for PTT was minimal comparing BLTR-3 and PLTR (adjusted risk difference [aRD] 1.8% (98.3%CI: -0.5-4.2%)), but significantly higher for BLTR-5 surgeries compared to BLTR-3 (aRD: 6.7% (3.9-9.4%)) and PLTR (aRD: 8.6% (5.9-11.3%)). BLTR-5 had the lowest ECA (6.1% versus 9.6% BLTR-3, 11.2% PLTR) and granuloma rates (5.2% versus 6.5% BLTR-3 and 7.5% PLTR). One eyelid operated with PLTR experienced an eyelid margin division; four BLTR-3 and eight BLTR-5 eyelids experienced excessive bleeding. INTERPRETATION: We do not recommend modifying the BLTR incision height of 3 mm. Overall, we did not find a significant difference in PTT between BLTR-3 and PLTR in terms of PTT or ECA. TRIAL REGISTRATION: Registration number: NCT03100747; ClinicalTrials.gov Full study protocol available at (https://doi.org/10.15139/S3/QHZXWD).

Trachoma-associated morbidity and mortality in Brazil: an ecological study focusing on hospitalization and mortality data, 2000-2022.

BACKGROUND: Trachoma is the leading infectious cause of blindness worldwide. It is a neglected tropical disease caused by Chlamydia trachomatis. The objective of this study was to analyze the trachoma-associated morbidity and mortality in Brazil from 2000 to 2022. This ecological time-series study was based on secondary data on trachoma obtained from hospital admissions (trachoma as the primary or secondary cause) and death certificates (trachoma as the underlying or associated cause). METHODS: We calculated the sex- and age-standardized rates of hospital admissions and trachoma-specific mortality according to sociodemographic variables and analyzed the spatial distribution. RESULTS: We identified 141/263,292,807 hospital admissions (primary cause: 83.0%) and 126/27,596,830 death certificates (associated cause: 91.3%) related to trachoma. Trachoma-related sequelae were reported in 8.5% of hospital admissions and 6.3% of death certificates. Trachoma was more common in males (hospital admissions and death certificates), people aged ≥70 years (hospital admissions and death certificates), those with brown skin (hospital admissions and death certificates), and those living in the North (hospital admissions) and Northeast (death certificates) regions of Brazil. CONCLUSIONS: Despite the relatively low rates of trachoma morbidity in Brazil, the associated mortality rates are of concern. The heterogeneous patterns of occurrence in the country in terms of population and territory reinforce the need to evaluate and monitor the available data, despite the low prevalence, in order to achieve and maintain the elimination targets in Brazil in the future.

Cirugía de la triquiasis tracomatosa. Tercera edición

En esta tercera edición se actualiza la definición de la triquiasis tracomatosa según lo acordado en la cuarta Reunión Científica Mundial sobre el Tracoma (Ginebra, del 27 al 29 de noviembre del 2018), se agrega una descripción sobre cómo examinar el entropión, se mejoran las listas de instrumentos y material fungible necesarios para la cirugía, se amplía y se mejora la orientación sobre los cuidados posoperatorios, se incluyen ilustraciones actualizadas, se mejora la presentación en todo el libro, y se elimina el contenido redundante.

Determinants of active trachoma among rural children aged 1-9 years old in Aw-Bare Wereda, Somali Region of Ethiopia: a cross-sectional study.

INTRODUCTION: Chronic and highly contagious, trachoma is a condition characterized by recurrent bacterial infection with ocular strains of Mycoplasma trachoma. It spreads through fingers, flies, and fomites, especially in situations where there is overcrowding. If untreated, the illness may result in blindness. Trachoma is an ancient disease and has previously been a significant public health problem in many areas of the world, including parts of Europe and North America. There are at least 400 million cases of active trachoma in the world, 8 million of which have resulted in blindness. Trachoma is a serious public health issue that is very common in Ethiopia. Therefore, the objective of this study is to identify the determinants of active trachoma among rural children aged 1-9 years old in Aw-bare woreda, Somali region of Ethiopia. METHOD: A cross-sectional community-based study involving children aged 1-9 who lived in six selected rural kebeles in the Awbare woreda Somali region and carried out using an ordinal logistic regression model. The study comprised 377 children in total. Our sample youngsters were chosen through a two-stage cluster sampling procedure. Then also chose our sample kebeles by simple random sampling. The main environmental, personal, and demographic factors that influenced the outcomes of active trachoma status were modeled using partial proportional odds modeling and descriptive statistics. RESULT: The study showed that the prevalence of active trachoma was found to be 47.7%. The covariate secondary level of education of mother OR = 1.357; 95% CI (1.051, 1.75), P-value = 0.0192, Inside house cooking place of children family OR = 0.789:95% CI (0.687, 0.927), P-value = 0.0031, children stay at home OR = 2.203:95%CI (1.526, 3.473), P-value = 0.0057,rich income family OR = 1.335:95%CI(1.166,1.528),P-value = 0.0001,Amount of water fetched per day OR = 2.129,95%CI(1.780,2.547),P-Vaue = 0.0001 were significant effect on active trachoma. PPOM represents the best fit as it has the smallest AIC and BIC. It is also more parsimonious. CONCLUSION: The mother's educational level, the location where the children spent the majority of their time indoors cooking, the fly density during the interview, the family's income, the child's age in years, the distance to the water source, the quantity of water fetched daily, and the number of people sharing a room have all been found to be significant predictors of the child's active trachoma status. Thus, increasing maternal education, access to clean water, and socioeconomic position are all crucial measures in preventing trachoma. Preventing trachoma also involves reducing the number of kids in a room and enhancing activities linked to personal cleanliness, such as giving kids a thorough facial wash to remove debris and discharge from their eyes.

Compliance with tetracycline eye ointment during annual mass drug administration for trachoma control in the Amhara region, Ethiopia.

OBJECTIVES: A 6-week course of tetracycline eye ointment is an alternative to single -dose oral azithromycin in annual mass drug administration for trachoma control. Compliance with the recommended tetracycline eye ointment regimen has not been well characterised when administered as part of a trachoma control program. METHODS: A routine mass drug administration for trachoma was carried out in 40 communities in the Amhara region of Ethiopia. Two tubes of tetracycline eye ointment, to be administered twice daily for 6 weeks, was offered to all children under 6 months of age, to pregnant women who declined to take azithromycin, and to all individuals with a macrolide allergy. Seven weeks following the mass drug administration, a treatment compliance survey was performed for all community members documented to have received tetracycline eye ointment during the mass drug administration. RESULTS: Of the 491 individuals documented as having received tetracycline eye ointment from the treatment records, 367 completed the survey, of which 214 recalled being offered tetracycline eye ointment. A total of 105 (49%) respondents reported taking ≥1 daily dose of tetracycline eye ointment on most days of the week for at least the first week. Only 20 (9%) respondents reported taking at least 1 tetracycline eye ointment dose per week for 6 weeks. The most common reasons for low compliance included 'saving it for a future infection' and 'stopped because I (or my child) seemed healthy'. The odds of low compliance were greater for those who reported not having adequate counselling (e.g., odds ratio [OR] 5.3, 95% CI 2.5-28.9 when low compliance was defined as not taking a tetracycline eye ointment dose for most days of at least the first week). CONCLUSIONS: Compliance with tetracycline eye ointment was low when administered by a trachoma program during a routine mass drug administration, especially for those reporting inadequate counselling. Further research with a larger sample size and varied settings is warranted to better understand and improve compliance.

Multimodal mucosal and systemic immune characterization of a non-human primate trachoma model highlights the critical role of local immunity during acute phase disease.

BACKGROUND: Trachoma is a leading cause of infection-related blindness worldwide. This disease is caused by recurrent Chlamydia trachomatis (Ct) infections of the conjunctiva and develops in two phases: i) active (acute trachoma, characterized by follicular conjunctivitis), then long-term: ii) scarring (chronic trachoma, characterized by conjunctival fibrosis, corneal opacification and eyelid malposition). Scarring trachoma is driven by the number and severity of reinfections. The immune system plays a pivotal role in trachoma including exacerbation of the disease. Hence the immune system may also be key to developing a trachoma vaccine. Therefore, we characterized clinical and local immune response kinetics in a non-human primate model of acute conjunctival Ct infection and disease. METHODOLOGY/PRINCIPAL FINDINGS: The conjunctiva of non-human primate (NHP, Cynomolgus monkeys-Macaca fascicularis-) were inoculated with Ct (B/Tunis-864 strain, B serovar). Clinical ocular monitoring was performed using a standardized photographic grading system, and local immune responses were assessed using multi-parameter flow cytometry of conjunctival cells, tear fluid cytokines, immunoglobulins, and Ct quantification. Clinical findings were similar to those observed during acute trachoma in humans, with the development of typical follicular conjunctivitis from the 4th week post-exposure to the 11th week. Immunologic analysis indicated an early phase influx of T cells in the conjunctiva and elevated interleukins 4, 8, and 5, followed by a late phase monocytic influx accompanied with a decrease in other immune cells, and tear fluid cytokines returning to initial levels. CONCLUSION/SIGNIFICANCE: Our NHP model accurately reproduces the clinical signs of acute trachoma, allowing for an accurate assessment of the local immune responses in infected eyes. A progressive immune response occurred for weeks after exposure to Ct, which subsided into a persistent innate immune response. An understanding of these local responses is the first step towards using the model to assess new vaccine and therapeutic strategies for disease prevention.

Comparison of metrics for assessing face washing behaviour for trachoma control.

There is currently no single, easy-to-use, reliable indicator to assess whether a face has been washed with soap in the context of trachoma elimination. This study aimed to compare survey report, script-based pictorial recall and facial cleanliness indicators as alternatives to structured observation for measuring face washing behaviour. This method validation study was nested in the Stronger-SAFE trial, Oromia Region, Ethiopia. Structured observation was conducted in randomly selected households for three hours from dawn. The primary caregiver in each household participated in a survey to capture (self)-reported behaviour and/or script-based pictorial recall, a routine-based diary activity to covertly capture information on face washing behaviour of themself and any children aged 1-12. Children 4-12 years old directly participated in the survey and pictorial recall in a subset of households. The facial cleanliness of children aged 1-12 was assessed qualitatively and using the quantitative Personal Hygiene Assessment Tool (qPHAT). Prevalence estimates, sensitivity, specificity and predictive values were computed for each behavioural indicator with observation data as the gold standard. The appropriateness of script-based pictorial recall was assessed using baseline and 3-month follow-up data. Baseline data were collected from 204 households in 68 clusters. Survey estimates of face washing and face washing with soap among caregivers and children were 32% to 60% and 5% to 31% higher than observed behaviour, respectively. Face washing prevalence estimates from pictorial recall were lower than survey estimates and comparable with observations for some face washing with soap indicators (0.3% to 13% higher than observations). Specificity of pictorial recall indicators was high (85% to 99%), but the sensitivity was low (0% to 67%), resulting in a low positive predictive value for all indicators. Both qualitative facial cleanliness indicators and qPHAT scores were poorly correlated with observed face washing earlier that morning. Pictorial recall overestimated face washing with soap among both caregivers and children following intervention delivery but not at baseline. Survey (self)-reported data on face washing is highly inaccurate. Script-based pictorial recall does not correctly classify those who wash their face with soap, and is subject to differential bias following intervention exposure, and facial cleanliness is a poor indicator of recent face washing in settings where faces become rapidly dirty again after washing. Alternatives to structured observation cannot be recommended to monitor the effectiveness of face washing interventions in community settings. Trial Registration ISRCTN registry ISRCTN40760473, https://doi.org/10.1186/ISRCTN40760473.

Association of polymorphisms of HSD11B1 and ACE genes with trachoma disease.

Trachoma, caused by Chlamydia trachomatis, is the most common infectious blindness in the world and is present in indigenous Mayan from Chiapas (Mexico). Inflammatory genes are activated when suffering from trachoma, thus some polymorphisms could increase the susceptibility to develop irreversible blindness. This study aimed to evaluate the genetic risk of developing late-stage trachoma in Mayan ethnic groups. In a case-control study (n = 51 vs n = 102, respectively), the following single-nucleotide polymorphisms (SNPs) in genes related to inflammation were analysed: HSD11B1 (rs11807619), HSD11B1 (rs932335), ABCG2 (rs2231142), SLCO1B1 (rs4149056), IL-10 (rs1800890), TNF (rs1800629), MMP2 (rs243865) and ACE. Three SNPs were associated with late-stage trachoma risk: (i) the T allele of rs11807619, (ii) the C allele of rs932335, which are linked to the HSD11B1 gene (OR = 22.5-27.3), particularly in men when adjusts for gender (OR = 16-16.7); and (iii) D allele of rs4340 in the ACE gene (OR = 5.2-5.3). In fact, significant linkage disequilibrium demonstrated association between ACE gene and HSD11B1 SNPs (r = 0.17-0.179; P = 0.0048-0.0073). Two SNPs HSD11B1 gene (P = 0.013 vs 0.0039) and HSD11B1-ACE haplotypes showed association with late-stage trachoma in Mayan ethnic groups.

The Epidemiology of Ocular Chlamydia trachomatis Infection within Districts Persistently Endemic for Trachoma in Amhara, Ethiopia.

Persistent trachoma is a growing concern to trachoma control programs globally and programs serving Ethiopia specifically. Persistent trachoma is defined as a district with two or more trachoma impact surveys (TISs) at which the prevalence of trachomatous inflammation-follicular (TF) among children ages 1-9 years is ≥5%, the elimination threshold. Because the global target for trachoma elimination as a public health problem is 2030, research is needed to better characterize persistent trachoma. This study described the epidemiology of ocular Chlamydia trachomatis infection, the causative bacteria of trachoma, in seven contiguous districts experiencing persistent trachoma. In 2019, multistage cluster random sampling TISs were conducted in the seven districts after 10 years of interventions. All individuals ages ≥1 year were examined for trachoma clinical signs by certified graders, and conjunctival swabs were collected from children ages 1-5 years to test for C. trachomatis infection. The district TF prevalence ranged from 11.8% (95% CI:7.6-16.0%) to 36.1% (95% CI:27.4-44.3%). The range of district-level C. trachomatis infection prevalence was between 2.7% and 34.4%. Statistically significant spatial clustering of high-infection communities was observed in the study districts, and children with infection were more likely than those without to be found in households with clinical signs of trachoma and those without latrines. These seven districts appear to constitute a persistent hotspot in Amhara, where an additional 3-5 years or more of interventions will be required. The global program will need to strengthen and enhance intervention strategies within persistent districts if elimination by 2030 is to be achieved.

Prevalence of active trachoma among 1-9 years of age children in Ethiopia: a systematic review and meta-analysis.

OBJECTIVE: The objective of this study is to determine the pooled prevalence of active trachoma among 1-9 years old children in Ethiopia. DESIGN: A systematic review and meta-analysis were employed in accordance with the Preferred Reporting Items for Systematic Reviews. DATA SOURCES: Medline/PubMed, Scopus, Web of Science, African Journal of Online and Google scholar databases were systematically explored to find studies published in English until July 2023. ELIGIBILITY CRITERIA: The following criteria apply: (1) condition (Co): studies examined the prevalence of trachoma among children (1-9) years old; (2) context (Co): studies conducted in Ethiopia; (3) population (Pop): studies that were done among children (1-9) years old; (4) study type: observational studies and (5) language: studies published in English. DATA EXTRACTION AND SYNTHESIS: The data were extracted using a Microsoft Excel spreadsheet. DerSimonian-Laird random effect model was used to estimate the pooled prevalence of active trachoma among 1-9 years old children. Cochrane Q-tests and I2 statistics were used across studies to assess heterogeneity. To identify possible publication bias, Egger's test was performed. PRIMARY OUTCOME: Prevalence of active trachoma among children aged (1-9 years old)". RESULTS: Overall, a total of 42 articles with 235 005 study participants were included in the final analysis. The estimated pooled prevalence of active trachoma using random effect model was 24% (95% CI 20% to 27%). The subgroup analysis by region revealed that the highest prevalence of trachoma was 36% (95% CI 13% to 58%) in the Tigray region, and publication year revealed the prevalence of trachoma was decreasing from 32% to 19% after 2015. CONCLUSION: In this review, the pooled prevalence of active trachoma was found to be high in Ethiopia compared with WHO threshold level. This underscores the need for increased focus on high-risk age groups to decrease trachoma and to achieve the elimination of trachoma from the country by 2030.

Photographic grading to evaluate facial cleanliness and trachoma among children in Amhara region, Ethiopia.

BACKGROUND: Promotion of facial cleanliness is recommended for the elimination of blinding trachoma, largely because of observational studies that have found an association between various measures of facial uncleanliness and trachoma. However, when a field grader assesses both facial cleanliness and trachoma, associations may be biased. Assessment of photographs of the face and conjunctiva by masked graders may provide a less biased estimate of the relationship between facial cleanliness and trachoma. METHODS: Face photographs, conjunctival photographs, and conjunctival swabs were obtained on a random sample of 0-9-year-old children from each of 40 communities in Amhara region, Ethiopia. Face photographs were assessed for the presence of seven measures of an unclean face (i.e., wet nasal discharge, dry nasal discharge, wet ocular discharge, dry ocular discharge, food, dust/dirt, and flies) by three independent masked photo-graders. Conjunctival photographs were similarly graded in a masked fashion for signs of clinically active trachoma. Conjunctival swabs were processed for Chlamydia trachomatis DNA. RESULTS: Of 2073 children with complete data, 808 (39%) had evidence of clinically active trachoma, 150 (7%) had evidence of ocular chlamydia infection, and 2524 (91%) had at least one measure of an unclean face. Dry ocular discharge had the strongest association with clinically active trachoma (age- and sex-adjusted prevalence ratio [PR] 1.4, 95% CI 1.2-1.6) and ocular chlamydia infection (PR 1.9, 95%CI 1.3-2.9), although significant associations were observed between each of the measures of facial uncleanliness and trachoma. CONCLUSIONS: Masked assessment of face and conjunctival photographs confirmed prior observational studies that have noted associations between various measures of facial uncleanliness and trachoma. The causal relationship between facial uncleanliness and trachoma is unclear since many features used to measure facial cleanliness (e.g., ocular discharge, nasal discharge, and flies) could be consequences of antecedent ocular chlamydia infection. TRIAL REGISTRATION: NCT02754583, clinicaltrials.gov.

Model of yearly transition to severe trachomatous scarring and trichiasis in a cohort of women in Kongwa Tanzania.

One criterion for validation of trachoma elimination is the management of Trachomatous Trichiasis (TT) after Trachoma inflammation-follicular (TF) is eliminated in children ages 1-9 years at district level. No data exist on how long countries must have dedicated TT programs, as the timeline for progression to TT from trachomatous scarring is unknown. We used eight years of longitudinal data in women in Kongwa Tanzania to model progression from no scarring (S0) through grades of scarring severity (S1-S4) to TT. Markov models were used, with age, community prevalence of TF (CPTF), and household characteristics as co-variates. Adjusted for covariates, the incidence of S1 was estimated at 4∙7% per year, and the risk increased by 26% if the CPTF was between 5-10% and by 48% if greater than 10%. The transition from S4 to TT was estimated at 2∙6% per year. Districts, even after elimination of TF, may have some communities with TF ≥ 5% and increased risk of incident scarring. Once scarring progresses to S2, further progression is not dependent on CPTF. These data suggest that, depending on the district level of scarring and degree of heterogeneity in CPTF at the time of elimination, incident TT will still be an issue for decades.

Active trachoma and associated factors in children aged 1 to 9 years living in Sasiga rural districts, East Wallaga Zone, Ethiopia, in 2022: a community- based cross-sectional study.

BACKGROUND: Trachoma, caused by the bacteria Chlamydia trachomatous, is a contagious eye condition that frequently affects children and quickly spreads from child to child and from child to caregiver. The study aimed to assess the distribution of active trachoma and its associated risk factors among children 1-9 years aged in Households of Sasiga Rural District, Western Ethiopia, in 2022. METHODS: A community-based cross-sectional study was conducted among 577 randomly selected children from March to May 2022. A multistage sampling technique was used. Data was collected through an interviewer-based questionnaire, physical observation, and clinical eye examinations. Epi Data 3.1 was used for data entry. The data were analyzed with SPSS version 24. Bivariate and multivariate binary logistic regressions were performed. In multivariable logistic regression analysis, the adjusted odds ratio with a 95% confidence interval was used to identify factors associated with active trachoma. A P-value of 0.05 was considered statistically significant. RESULTS: The distribution of Active Trachoma among children 1-9 years aged in Households of the study area was 9.5%(95%CI:7.11,11.89). Being from a low-income household with a monthly income of less than 1500 ETB [AOR = 3.49, 95% CI: 1.39, 8.75], Households where the nearest water supply is more than 30 min away [AOR = 8.34, 95%CI: 1.89, 36.73], households with only one room [AOR = 2.98, 95%CI: 1.027, 8.68], and presence of feces in the compound of the households [AOR = 3.08, 95%CI: 1.41, 6.75] were associated with active trachoma in 1-9 years aged children living in the study setting. CONCLUSION: The distribution of Active Trachoma among children 1-9 years aged in Households of the study area was found to be high. Monthly income, the time it took to get water for home use, and the presence of feces in household compounds were all linked to active trachoma in children living in the study area. As a result, continuous sanitary education on trachoma transmission and prevention should be strengthened in the district.

Field- and laboratory-based studies on correlates of Chlamydia trachomatis transmission by Musca sorbens: Determinants of fly-eye contact and investigations into fly carriage of elementary bodies.

Musca sorbens (Diptera: Muscidae) flies are thought to be vectors of the blinding eye disease trachoma, carrying the bacterium Chlamydia trachomatis (Ct) between the eyes of individuals. While their role as vectors has been convincingly demonstrated via randomised controlled trials in The Gambia, studies of fly-borne trachoma transmission remain scant and as such our understanding of their ability to transmit Ct remains poor. We examined fly-eye contact and caught eye-seeking flies from 494 individuals (79% aged ≤9 years) in Oromia, Ethiopia. Ct-carrying flies (harbouring Ct DNA) were found to cluster spatially in and nearby to households in which at least one resident had Ct infection. Fly-eye contact was positively associated with the presence of trachoma (disease), lower human body weight and increased human body temperature. Studies of laboratory-reared M. sorbens indicated that Ct is found both externally and internally following feeds on Ct culture, with scanning electron microscopy revealing how Ct bodies can cling to fly hairs (setae). Testing for Ct on field-caught M. sorbens found fly 'bodies' (thorax, wings and abdomen) to consistently test positive for Ct while legs and heads were infrequently Ct-positive. These studies strongly support the role of M. sorbens as vectors of trachoma and highlight the need for improved understanding of fly-borne trachoma transmission dynamics and vector competence.

Severity of Trachomatous Scarring among Adults in Trachoma-Endemic Amhara Region of Ethiopia.

Trachomatous scarring has been shown to progress regardless of active ocular Chlamydia trachomatis infection, indicating that scarring drivers may be unrelated to ongoing transmission. Although scarring prevalence is commonly associated with older age and female sex, less is known about other potential contributors to its development. This study identified and assessed risk factors associated with scarring magnitude in a trachoma-endemic setting, utilizing a five-point photographic scale (S0-S4). During 2017 trachoma surveys of Amhara, Ethiopia, photographers captured left and right conjunctival images of adults (ages 15 years and older) from 10 districts. Subsequently, two graders independently assessed photographs for scarring, with discrepancies adjudicated by an expert grader. Scarring scores for 729 individuals were aggregated from the eye level to the participant level, excluding 17 participants because of poor photograph quality. Among those with scarring, most cases (20.4%) were severe (S4, comprising more than 90% of the tarsal conjunctiva) compared with the prevalence of moderate S3-A/B (11.2%), S2 (8.3%), and mild S1 (19.2%). The youngest group (ages 15-19 years) exhibited all scarring stages. Older participants (60 years and older) experienced a greater burden of severe scarring (S4 prevalence: 32.6%) than their younger (15-19 years) counterparts (6.2%). Multivariate ordinal logistic regression models indicated female sex, increasing age, and district-level trachomatous follicular-inflammation prevalence were significant predictors of scarring severity. Trachomatous scarring and its progression to trichiasis, may prove a barrier to meeting WHO timelines for trachoma elimination and will necessitate ongoing surveillance and interventions after elimination thresholds have been met.