Epidemiology and control of trachoma: systematic review

2025 European guideline on the management of Chlamydia trachomatis infections

Sexually transmitted Chlamydia trachomatis infections remain common globally and most frequently are asymptomatic. The 2025 European C. trachomatis guideline provides up-to-date guidance regarding indications for testing and treatment of C. trachomatis infections. It includes advice on urogenital and extragenital C. trachomatis testing including the use of self-collected specimens; recommendation to use only validated NAATs for diagnosis; and recommendation to treat all C. trachomatis infections with doxycycline as first line in preference to single-dose azithromycin regimens. The absence of evidence and limited value of broad screening in asymptomatic populations for C. trachomatis infections is also discussed.

Trachoma in Sudan: Risk Factors and Clinical Stages in Patients From Two Eye Care Hospitals, 2015

Background Trachoma is a leading infectious cause of blindness globally. While it has largely been eliminated in developed countries, it remains endemic in many developing regions. This study aimed to examine the clinical stages of trachoma and identify common sociodemographic and household characteristics associated with the disease among patients in Sudan. Methods We conducted a prospective, hospital-based descriptive cross-sectional study at Makah Eye Complex and Abdalfadeel-Almaz Hospital in Khartoum, Sudan. The study included trachoma patients of all age groups who visited these two eye care hospitals between March 1 and March 31, 2015. Data were gathered through clinical examinations, hospital records, and face-to-face interviews using a structured questionnaire. Results In this study, we identified 125 patients with trachoma, of whom 98 (78.4%) were over 50 years old. A majority, 70 (56%), tested positive for active trachoma; 51 (40.8%) had trachomatous trichiasis; and 70 (56%) exhibited trachoma follicles. Most patients were found to have low socioeconomic status (110, 88%), poor personal hygiene (55, 44%), and poor environmental hygiene (93, 74.4%). Conclusions Low socioeconomic status, poor personal hygiene, and inadequate environmental hygiene are prevalent sociodemographic and household characteristics among patients with trachoma. Despite significant progress toward disease elimination, trachoma continues to pose a public health challenge in Sudan.

Koala ocular disease grades are defined by chlamydial load changes and increases in Th2 immune responses

Introduction

This study employs bulk RNA sequencing, PCR, and ELISA assays to analyze the pathological factors affecting the outcomes of C. pecorum ocular infections in koalas. It investigates the immune responses and gene expression profiles associated with various stages of koala ocular chlamydiosis.

Methods

A cohort of 114 koalas from Queensland, Australia were assessed, with 47% displaying clinical signs of ocular disease. Animals were classified into three cohorts: acute active disease (G1), chronic active disease (G2), and chronic inactive disease (G3), along with subclinical Chlamydia pecorum positive (H2) and healthy (H1) cohorts.

Results

Analysis of clinical, microbiological, humoral immune and cellular immune biomarkers revealed varying chlamydial loads and anti-chlamydial IgG levels across disease grades, with a negative correlation observed between ocular chlamydial load and anti-chlamydial IgG. Koala ocular mucosa gene expression analysis from 27 koalas identified shared expression pathways across disease cohorts, with a significant upregulation of IFNγ expression and tryptophan metabolism in all disease stages.

Discussion

These findings help elucidate immune response dynamics and molecular pathways underlying koala ocular chlamydiosis, providing insights crucial for disease management strategies.

"The blinding disease". The history of trachoma in Italians between the 19th and 20th centuries: colonial or national blindness?

Trachoma is one of the oldest known causes of blindness in humans and it is caused by the intracellular Gram-negative bacterium Chlamydia trachomatis serovars A, B, Ba and C. Its transmission has historically been related to poorness, overcrowded housing and scarce hygiene. We have traced the history of trachoma in Italy in the 19th and 20th centuries, among people living in Italy, those who immigrated to America and the population in the colonies, with a focus on Libya (1912-1943). Trachoma knowledge and perception in Italy and in its colonies was ambiguous during the 19th and 20th centuries. Trachoma was responsible for a great morbidity on both sides of the Mediterranean, in Italy as well as in Libya. Trachoma is still one of the leading infectious causes of preventable blindness worldwide and it was widespread in Italy and the Italian colonies in the first half of the last century.

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.

Infectious eye disease in the 21st century-an overview

Infectious diseases affecting the eye often cause unilateral or asymmetric visual loss in children and people of working age. This group of conditions includes viral, bacterial, fungal and parasitic diseases, both common and rare presentations which, in aggregate, may account for a significant portion of the global visual burden. Diagnosis is frequently challenging even in specialist centres, and many disease presentations are highly regional. In an age of globalisation, an understanding of the various modes of transmission and the geographic distribution of infections can be instructive to clinicians. The impact of eye infections on global disability is currently not sufficiently captured in global prevalence studies on visual impairment and blindness, which focus on bilateral disease in the over-50s. Moreover, in many cases it is hard to differentiate between infectious and immune-mediated diseases. Since infectious eye diseases can be preventable and frequently affect younger people, we argue that in future prevalence studies they should be considered as a separate category, including estimates of disability-adjusted life years (DALY) as a measure of overall disease burden. Numbers of ocular infections are uniquely affected by outbreaks as well as endemic transmission, and their control frequently relies on collaborative partnerships that go well beyond the remit of ophthalmology, encompassing domains as various as vaccination, antibiotic development, individual healthcare, vector control, mass drug administration, food supplementation, environmental and food hygiene, epidemiological mapping, and many more. Moreover, the anticipated impacts of global warming, conflict, food poverty, urbanisation and environmental degradation are likely to magnify their importance. While remote telemedicine can be a useful aide in the diagnosis of these conditions in resource-poor areas, enhanced global reporting networks and artificial intelligence systems may ultimately be required for disease surveillance and monitoring.

Navigating diagnostic and therapeutic challenges in ocular manifestations of Hansen's disease and trachoma: A narrative review

Neglected tropical diseases (NTDs) encompass a group of approximately 20 diseases prevalent in tropical and subtropical regions, closely associated with poverty, affecting over a billion people in low-income countries. This manuscript aims to explore the ocular manifestations and burden of two significant NTDs, namely Hansen's disease and trachoma while addressing gaps in understanding and management. Hansen's disease, caused by Mycobacterium leprae , has a long history and presents with diverse neurological and ocular manifestations. Despite the availability of treatment, ocular complications persist, leading to significant visual impairment in some cases. The manuscript emphasizes the importance of early diagnosis, regular ophthalmic examinations, and follow-ups to prevent and control ocular complications, reducing the burden of visual impairment and blindness. Trachoma, caused by Chlamydia trachomatis , remains the leading infectious cause of blindness in underdeveloped and remote areas. The manuscript highlights the clinical diagnosis and implementation of the World Health Organization's (WHO's) SAFE (surgery, antibiotics, facial hygiene, and environmental sanitation) strategy to prevent transmission and associated blindness. However, challenges in health surveillance tools and underreporting of trachoma cases are addressed, emphasizing the need for improved strategies to combat the disease effectively. Through a comprehensive review of the ocular manifestations and management of Hansen's disease and trachoma, this manuscript contributes to the existing knowledge base and enhances a deeper understanding of these NTDs. Addressing gaps in understanding and management emphasizes the importance of implementing WHO's strategies and collaborative efforts to achieve the global goal of reducing the burden of NTDs and improving community health and well-being. The manuscript underscores the significance of early intervention, preventive measures, and technological advancements, providing valuable insights for policymakers, healthcare professionals, and researchers working in the field of NTDs.

Stability indicating high performance thin layer chromatography method development and validation for quantitative determination of tetracycline hydrochloride in tetracycline hydrochloride active pharmaceutical ingredient (API) and its dosage forms

Simple, quick, cost-effective, and environmentally friendly analytical methods for quality assurance and control roles for different medicines, including Tetrcyclines, are most significantly needed. Also, different thin layer chromatography (TLC)-based methods for tetracycline identification exist, but high performance thin layer chromatography methods based on modern state- of- the art equipment are still nonexistent. Thus, in this study, analytical method development and verification were done by high performance thin layer chromatography (HPTLC) (using an automated equipment model) using glass plates coated with silica gel 60 F254 after treating with 10% Na2EDTA. Validation was carried out according to International Council for Harmonization (ICH) guidelines. A mobile phase formed from ethyl acetate, acetonitrile, methanol, and 1% aqueous ammonia in the composition of 4.4:19.6:10:6 volume to volume ratio (V/V) was used. Rf value, percentage recoveries, linearity ranges, limit of detection (LOD), and limit of quantitation (LOQ) for the developed HPTLC method were 0.28, 100.83-106.25%, 160-560 ng/band (r2 values of 0.9999), 31.9 ng/band, and 96.7 ng/band, respectively. The results of the sample assays conducted using the new method and the United States Pharmacopoeia (USP) high performance liquid chromatography (HPLC) method were 91.59% to 108.3% and 90.83% to 102.85%, respectively. The F test for the aforementioned methods was 2.01, which is smaller than the tabulated F value of 5.05 with 5 degrees of freedom at a 95% confidence range, proving that the newly developed HPTLC and HPLC pharmacopoeial methods can be used interchangeably.The newly developed HPTLC method is easy, economical, specific, accurate, and roboust, thus it can be employed in a range of settings that require quality control and assurance activities of tetracycline hydrochloride (TC-HCl) in bulk and ointment dosage forms.

High prevalence of trachomatous inflammation-follicular with no trachomatous trichiasis: can alternative indicators explain the epidemiology of trachoma in Côte d'Ivoire?

Baseline trachoma surveys in Côte d'Ivoire (2019) identified seven evaluation units (EUs) with a trachomatous inflammation-follicular (TF) prevalence ≥10%, but a trachomatous trichiasis (TT) prevalence in individuals ≥15 y of age below the elimination threshold (0.2%). Two of these EUs, Bondoukou 1 and Bangolo 2, were selected for a follow-up survey to understand the epidemiology of trachoma using additional indicators of Chlamydia trachomatis infection (DNA from conjunctival swabs) and exposure (anti-Pgp3 and Ct694 antibodies from dried blood spots [DBSs]). A two-stage cluster sampling methodology was used to select villages and households. All individuals 1-9 y of age from each selected household were recruited, graded for trachoma and had a conjunctival swab and DBS collected. Conjunctival swabs and DBSs were tested using Cepheid GeneXpert and a multiplex bead assay, respectively. The age-adjusted TF and infection prevalence in 1- to 9-year-olds was <1% and <0.3% in both EUs. Age-adjusted seroprevalence was 5.3% (95% confidence interval [CI] 1.5 to 15.6) in Bondoukou 1 and 8.2% (95% CI 4.3 to 13.7) in Bangolo 2. The seroconversion rate for Pgp3 was low, at 1.23 seroconversions/100 children/year (95% CI 0.78 to 1.75) in Bondoukou 1 and 1.91 (95% CI 1.58 to 2.24) in Bangolo 2. Similar results were seen for CT694. These infection, antibody and clinical data provide strong evidence that trachoma is not a public health problem in either EU.

Longitudinal changes in tear cytokines and antimicrobial proteins in trachomatous disease

BACKGROUND

Trachoma is a neglected tropical disease caused by ocular infection with Chlamydia trachomatis, where repeated infections and chronic inflammation can ultimately result in scarring, trichiasis and blindness. While scarring is thought to be mediated by a dysregulated immune response, the kinetics of cytokines and antimicrobial proteins in the tear film have not yet been characterised.

METHODOLOGY

Pooled tears from a Gambian cohort and Tanzanian cohort were semi-quantitatively screened using a Proteome Profiler Array to identify cytokines differentially regulated in disease. Based on this screen and previous literature, ten cytokines (CXCL1, IP-10, IFN-γ, IL-1β, IL-8, IL-10, IL-12 p40, IL-1RA, IL-1α and PDGF), lysozyme and lactoferrin were assayed in the Tanzanian cohort by multiplex cytokine assay and ELISA. Finally, CXCL1, IP-10, IL-8, lysozyme and lactoferrin were longitudinally profiled in the Gambian cohort by multiplex cytokine assay and ELISA.

RESULTS

In the Tanzanian cohort, IL-8 was significantly increased in those with clinically inapparent infection (p = 0.0086). Lysozyme, IL-10 and chemokines CXCL1 and IL-8 were increased in scarring (p = 0.016, 0.046, 0.016, and 0.037). CXCL1, IP-10, IL-8, lysozyme and lactoferrin were longitudinally profiled over the course of infection in a Gambian cohort study, with evidence of an inflammatory response both before, during and after detectable infection. CXCL1, IL-8 and IP-10 were higher in the second infection episode relative to the first (p = 0.0012, 0.044, and 0.04).

CONCLUSIONS

These findings suggest that the ocular immune system responds prior to and continues to respond after detectable C. trachomatis infection, possibly due to a positive feedback loop inducing immune activation. Levels of CXC chemokines in successive infection episodes were increased, which may offer an explanation as to why repeated infections are a risk factor for scarring.

Knowledge, Attitudes, and Practices of Hygiene and the Prevention of Trachoma in the Indigenous Population of the Colombian Amazon Vaupés Department

The Colombian program to end trachoma implements the component F of the SAFE strategy in the Vaupés department of the Amazon rainforest. Cultural, linguistic, and geographical barriers and the coexistence of an ancestral medical system demand the technical and sociocultural adaptation of this component. A cross-sectional survey combined with focus-group discussions to understand the knowledge, attitudes, and practices of the indigenous population related to trachoma was conducted in 2015. Of the 357 heads of households that participated, 45.1% associated trachoma with a lack of hygiene, and 94.7% associated the concept of hygiene with taking one or more body baths per day, using commercial or handcrafted soap. In total, 93% reported cleaning their children's faces and eyes more often when they have conjunctivitis, but 66.1% also did this with clothes or towels in use, and 52.7% of people shared towels; in total, 32.8% indicated that they would use ancestral medicine to prevent and treat trachoma. The SAFE strategy in Vaupés requires an intercultural approach to facilitate stakeholder support and participation to promote general and facial hygiene, washing clothes with soap, and not sharing towels and clothes to dry and clean children's faces for effective and sustainable elimination of trachoma as a public health problem. This qualitative assessment facilitated an intercultural approach locally and in other Amazonian locations.

Chlamydia trachomatis induces the transcriptional activity of host YAP in a Hippo-independent fashion

Introduction

The obligate intracellular pathogen Chlamydia trachomatis is the causative agent of the most common bacterial sexually transmitted disease worldwide. While the host response to infection by this pathogen has been well characterized, it remains unclear to what extent host gene expression during infection is the product of Chlamydia-directed modulation of host transcription factors.

Methods

To identify transcription factors potentially modulated by Chlamydia during infection, we infected immortalized endocervical epithelial cells (End1/E6E7) with the anogenital C. trachomatis serovar L2, harvesting polyadenylated RNA for bulk RNA-sequencing. Subsequent experiments elucidating the mechanism of infection-mediated YAP activation assayed YAP target gene expression via qRT-PCR, YAP nuclear translocation via quantitative immunofluorescence, and YAP phosphorylation via Western blotting.

Results

RNA sequencing of Chlamydia-infected endocervical epithelial cells revealed gene expression consistent with activity of YAP, a transcriptional coactivator implicated in cell proliferation, wound healing, and fibrosis. After confirming induction of YAP target genes during infection, we observed an infection-dependent increase in YAP nuclear translocation sensitive to inhibition of bacterial protein synthesis. While Hippo-mediated phosphoinhibition of YAP at S127 was unaffected by C. trachomatis infection, Hippo-independent phosphorylation at Y357 was increased. Infection did not enhance nuclear translocation of Y357F mutant YAP, illustrating a requirement for phosphorylation at this residue. Pharmacological inhibition of host Src-family kinase activity attenuated YAP Y357 phosphorylation, but not nuclear translocation - which was instead sensitive to inhibition of Abl.

Discussion

Our results define a transcriptome-altering mechanism of pathogen-directed YAP activation that bypasses canonical inhibition by the Hippo kinase cascade, with a potential link to chlamydial fibrosis and other advanced disease sequelae. Additional study is required to determine the specific role of infection-associated Y357 phosphorylation and Abl activity in chlamydial induction of YAP.

Trachoma, the world's leading infectious cause of blindness: The remaining gap in care and access to basic handwashing facilities

PURPOSE

Trachoma, the world's leading infectious cause of blindness, has been targeted by the WHO for elimination through the SAFE strategy: surgery, antibiotics, facial cleanliness, and environmental improvement. Although significant progress has been made, there remains a gap in care. This project studied the association of geographical distribution of the remaining need for trachoma intervention and its association with access to basic handwashing facilities at home, as an indicator of water/sanitation infrastructure. We hypothesized that poor water sanitation would correspond to areas where trachoma intervention is still required.

DESIGN

Retrospective analysis using the WHO Global Health Observatory. Spatial, correlation, and simple and multivariable regression analyses were used.

METHODS

Using data from the WHO Global Health Observatory, a total of 194 countries were analyzed. Two choropleth maps were created, with inset maps focused on the South Pacific region, where the top 5 countries with the greatest population proportion requiring trachoma intervention are located.

RESULTS

Correlations and the simple regression model of total population with access to handwashing facilities as the only risk factor were insignificant. However, the multivariable regression models with access to handwashing facilities (total, urban, and rural) and population density as risk factors for trachoma intervention were significant.

CONCLUSION

Poor water/sanitation infrastructure correlates with trachoma burden. Therefore, water/sanitation infrastructure improvement is a worthwhile target in the efforts toward trachoma elimination, but further research on the association between these important public health indicators is warranted.

Prospective audit of the phenotype, causes and correlates of trachomatous and non- trachomatous trichiasis in a peri-elimination setting

PURPOSE

To explore the burden, clinical features and associations of trichiasis due to trachomatous and non-trachomatous aetiologies.

METHODS

Consenting patients presenting with trichiasis of either eyelid (of one or both eyes) attending the outpatient department, cornea and oculoplasty clinics of a tertiary eye care hospital in New Delhi between August 2018 to March 2020 were included. A comprehensive examination including visual acuity and anterior segment evaluation and photography was performed. Grade of trichiasis, laterality, presence and grade of entropion, and information on corneal opacity, conjunctival scarring, Herbert's pits, and pannus, if present, were recorded in the case record form.

RESULTS

Overall, 302 patients (454 eyes) with trichiasis were recruited. The most common attributed cause of upper eyelid trichiasis (276 patients, 405 eyes) was trachoma (26% of patients), followed by Stevens-Johnson syndrome (23%), blepharokeratoconjunctivitis (17%) and old age (10%). A total of 296/405 eyes (73%) had some form of corneal involvement. Trachoma was not identified as the cause of trichiasis in any eye with lower eyelid-only disease.

CONCLUSION

Only about a quarter of upper eyelid trichiasis in this peri-elimination setting was attributed to trachoma. A distinction between trachomatous and non-trachomatous trichiasis is imperative to meaningfully determine whether elimination of trachoma as a public health problem has occurred. These data may have implications for population-based estimates of TT prevalence in India and other peri-elimination settings.

Perceptions and practices of community members relating to trachoma in Africa: a qualitative systematic review

OBJECTIVE

The objective of this review was to synthesize the perceptions and practices of community members relating to trachoma in Africa.

INTRODUCTION

Trachoma is the leading cause of blindness worldwide, and Africa is the worst-affected continent. Synthesized evidence relating to the disease has focused on various aspects including epidemiology, control, health education, facial cleanliness, interventions for trachomatous trichiasis, and the burden of trachoma on women. Currently, systematic reviews on perceptions and practices relating to trachoma are lacking despite the existence of primary studies. Filling this knowledge gap is critical for decision-making for effective community uptake of interventions.

INCLUSION CRITERIA

Qualitative studies on the perceptions and practices relating to trachoma in both health care and community settings in Africa were considered for inclusion. Studies with participants 14 years or older were considered, regardless of gender, health status, religion, or ethnicity. Perceptions included beliefs, perspectives, views, knowledge, and thoughts relating to trachoma. Practices included regular actions relating to trachoma, such as treatment and prevention behaviors.

METHODS

A search for studies in English was conducted in MEDLINE, CINAHL, Embase, PsycINFO, Sociological Abstracts, BioMed Central, Current Contents, Cochrane Library, and Google Scholar in May 2019 and updated in October 2021. Unpublished studies were searched in MedNar, Index to Thesis, ProQuest Dissertations and Theses Global, World Health Organization, and individual governments' commissioned trachoma reports. Two independent reviewers were involved in study selection, critical appraisal, and data extraction using the JBI tools. Data were synthesized using the JBI meta-aggregative approach.

RESULTS

Seven studies were included in this review. Participants were people either with or without trachoma. A total of 90 findings were extracted, from which 10 categories were produced and three synthesized findings derived from the categories. The synthesized findings are: understanding and awareness of trachoma influences perceptions of treatment and preventive methods; beliefs and behaviors influence treatment options; economic constraints, socio-cultural beliefs, and risk perceptions influence prevention behaviors and practices.

CONCLUSION

Various perceptions and practices relating to trachoma exist among community members in Africa. These perceptions and practices are influenced by knowledge, cultural beliefs, economic factors, and environmental factors. The findings suggest the need for decision-makers in policy and practice to consider and include these perceptions and practices when designing interventions to combat trachoma in endemic countries. However, due to the limited number of included studies and their methodological weaknesses, more high-quality studies are needed to have a deeper and broader view on these perceptions and practices.

Associated factors of the co-occurrence of trachoma and soil-transmitted helminthiases in children 1 to 9 years old in rural communities of the Amazon basin in Loreto Department, Peru: Results from a population-based survey

BACKGROUND

There is evidence of the occurrence of trachoma in Peru, and studies have shown that soil-transmitted helminthiases (STH) are affecting rural communities in the Amazon basin in Loreto Department. This study was done to estimate trachoma prevalence, STH prevalence, and the associated factors for both diseases in children aged 1-9 years in rural communities of Peru.

METHODOLOGY

A population-based cross-sectional survey was carried out in rural communities of Loreto. A standardized survey questionnaire with individual and household risk factors related to both diseases was used. Ocular examination was done for all participants aged one year and above, and eye swab samples were collected from children with follicular trachoma (TF). Anthropometric measurements, stool samples for STH, and blood samples for hemoglobin measurement were taken from children.

PRINCIPAL FINDINGS

TF prevalence was 7.74% (95% CI 5.08-11.63%), STH prevalence was 49.49% (95% CI 25.00-52.43%), and prevalence of co-occurrence of both diseases was 5.06% (95% CI 2.80-8.98%) in children aged 1-9 years. Being at age 3-8 years old (AOR = 6.76; 95% CI 1.346-33.947), have an unclean face (AOR = 24.64; 95% CI 6.787-89.444), and having been dewormed in the last six months (AOR = 2.47; 95% CI 1.106-5.514), were risk factors of TF. Being a female (AOR = 0.22; 95% CI 0.103-0.457) was associated with decreased odds of TF. Having been dewormed in the last six months (AOR = 0.30; 95% CI 0.139-0.628) was a preventative factor for STH. Risk factors for children with both diseases mirrored the findings for risk factors for individual diseases.

CONCLUSIONS

Neglected tropical diseases and associated risk factors overlap in communities living in vulnerable conditions in the Amazon basin of Peru. These findings support the need to implement integrated interventions, including mass drug administration, water, sanitation, and hygiene for both diseases in the study area.

Community-level trachoma ecological associations and the use of geospatial analysis methods: A systematic review

Background

Trachoma is targeted for global elimination as a public health problem by 2030. Understanding individual, household, or community-associated factors that may lead to continued transmission or risk of recrudescence in areas where elimination has previously been achieved, is essential in reaching and maintaining trachoma elimination. We aimed to identify climatic, demographic, environmental, infrastructural, and socioeconomic factors associated in the literature with trachoma at community-level and assess the strength of their association with trachoma. Because of the potential power of geospatial analysis to delineate the variables most strongly associated with differences in trachoma prevalence, we then looked in detail at geospatial analysis methods used in previous trachoma studies.

Methods

We conducted a systematic literature review using five databases: Medline, Embase, Global Health, Dissertations & Theses Global, and Web of Science, including publications from January 1950 to January 2021. The review protocol was prospectively registered with PROSPERO (CRD42020191718).

Results

Of 35 eligible studies, 29 included 59 different trachoma-associated factors, with eight studies also including spatial analysis methods. Six studies included spatial analysis methods only. Higher trachomatous inflammation—follicular (TF) prevalence was associated with areas that: had lower mean annual precipitation, lower mean annual temperatures, and lower altitudes; were rural, were less accessible, had fewer medical services, had fewer schools; and had lower access to water and sanitation. Higher trachomatous trichiasis (TT) prevalence was associated with higher aridity index and increased distance to stable nightlights. Of the 14 studies that included spatial methods, 11 used exploratory spatial data analysis methods, three used interpolation methods, and seven used spatial modelling methods.

Conclusion

Researchers and decision-makers should consider the inclusion and potential influence of trachoma-associated factors as part of both research activities and programmatic priorities. The use of geospatial methods in trachoma studies remains limited but offers the potential to define disease hotspots and areas of potential recrudescence to inform local, national, and global programmatic needs.

The ambitious target to eliminate trachoma as a public health problem has led to impressive strides in reducing the disease burden worldwide, with the implementation of the World Health Organization (WHO)-endorsed surgery, antibiotics, facial cleanliness and environmental improvement (SAFE) strategy. However, some areas have struggled to reach the elimination threshold after the prescribed number of antibiotic mass drug administration rounds, and some areas have had evidence of trachoma recrudescence after previously having reached the elimination threshold. This systematic review assessed climatic, demographic, environmental, infrastructural, and socioeconomic factors associated with trachoma to reveal which covariates are associated with ongoing or renewed trachoma transmission. We also explored how geospatial analysis, which could help identify areas with ongoing trachoma transmission or heightened risk of recrudescence, has been used in previous trachoma studies. Thirty-five studies met the inclusion criteria for the review. Results indicated that researchers and decision-makers should consider the inclusion and potential influence of precipitation, temperature, and altitude along with variables related to ruralness, accessibility, access to medical services and schools, and community-level water and sanitation coverage, as part of both research activities and programmatic priorities for trachoma elimination.

AAUS guideline for chlamydial urethritis

Urogenital chlamydial infection is the most common sexually transmitted infection. Many cases of chlamydial infection are reported worldwide every year. Genital chlamydial infection in women can also cause obstetric issues, including infertility and miscarriage. For that purpose, appropriate care should be conducted with the latest knowledge. Only few guidelines come from Asian countries. The Asian Association of Urinary Tract Infection and Sexually Transmitted Infection (AAUS) belonging to the Urological Association of Asia (UAA) had developed the guidelines regarding chlamydial urethritis. We have collected the feedback and updated the guidelines which is now submitted for consideration of publication. In addition to the levels of evidence, the recommendation grades were defined using the modified GRADE methodology. Herein, we present the new edition of the UAA-AAUS guidelines for chlamydial urethritis.

The impact of access to water supply and sanitation on the prevalence of active trachoma in Ethiopia: A systematic review and meta-analysis

Background

Trachoma is a worldwide infectious disease causing blindness. Trachoma continued as a public health problem in Ethiopia due to a lack of sanitation and inadequate prevention strategies. This study aimed to identify the impact of water supply and sanitation intervention on preventing active trachoma among children.

Methods

Systematic literature searches were performed from 4 international databases. The search involved articles published from January 1995 up to March 2019. The Cochran Q and I² statistical tests were used to check heterogeneity among the studies. A random-effect meta-analysis was employed to determine the pooled estimates with a 95% confidence interval (CI). Data analysis was performed using the CMA V.3 and RevMan 5 software program, and the result of the systematic review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Findings

Out of 211 studies screened for the analysis, only 29 studies were finally included in this systematic review and meta-analysis. The result revealed factors that are significantly associated with increased odds of active trachoma. Accordingly, households with no access to toilet facilities (odds ratio [OR]: 2.04, 95% CI: 1.75–2.38), no access to improved water (OR: 1.58, 95% CI: 1.27–1.96), and do not practice regular face washing for children (OR: 4.19, 95% CI: 3.02–5.81) have shown increased odds of active trachoma. Besides, the results show a higher prevalence of active trachoma among children who did not wash their faces with soap and frequently.

Conclusions

The study found strong evidence that lack of access to water, sanitation, and hygiene (WASH) was associated with increased prevalence of active trachoma among children. Therefore, a comprehensive and partnership-oriented program is needed to tackle the problem, but further study will be required to strengthen its implementation.

Implementing trachoma control programmes in marginalised populations in Tanzania: A qualitative study exploring the experiences and perspectives of key stakeholders

BACKGROUND

Despite aspects of the SAFE strategy for reducing trachoma in Tanzania have been somewhat successful, the disease still persists in marginalised communities even with repeated trachoma control interventions. This study aims to understand the facilitators and barriers associated with implementing trachoma control programmes in these communities, from the perspective of non-governmental organisations (NGOs).

METHODS

Participants were the representatives of NGOs who had knowledge and experience in the implementation of trachoma control programmes. Data was collected using in-depth, semi-structured interviews guided by a topic guide, which was updated after each interview using a constant comparative method. Interviews were audio-recorded and then transcribed verbatim. Thematic analysis was done inductively. Codes were generated from the transcripts and then clustered into themes.

FINDINGS

The context within marginalised communities often acted as a perceived barrier to successful implementation of control programmes. This included poor environmental cleanliness, lack of trust, poor disease knowledge and traditional lifestyles. Community values could either be a facilitator or a barrier, depending on the scenario. The anatomical location of the disease and the poor understanding of the disease progression also served as barriers. Considerations affecting decision-making among NGO's include financial feasibility, community needs and whether the quality of the intervention could be improved. NGOs felt that the collaboration and the opportunity to learn from other organisations were beneficial aspects of having different actors. However, this also resulted in variability in the effectiveness of interventions between districts.

CONCLUSION

NGOs should focus on behaviour change and health education that is tailored to marginalised communities and seek innovative ways to implement trachoma intervention programmes whilst being minimally intrusive to the traditional way of life. Partners should also implement ways to ensure high quality programmes are being provided, by increasing staff accountability and compensating volunteers fairly.

Chlamydia suis is associated with intestinal NF-κB activation in experimentally infected gnotobiotic piglets

Chlamydia suis intestinal infection of single-animal experimental groups of gnotobiotic newborn piglets was previously reported to cause severe, temporary small intestinal epithelium damage. We investigated archived intestinal samples for pro-inflammatory nuclear factor kappa B (NF-κB) activation, Interleukin (IL)-6 and IL-8 production and immune cell influx. Samples were collected 2, 4 and 7 days post-inoculation with C. suis strain S45/6 or mock inoculum (control). Increased nuclear localization of epithelial NF-κB, representative of activation, in the jejunum and ileum of C. suis-infected animals, compared to uninfected controls, began by 2 days post-infection (dpi) and persisted through 7 dpi. Infected animals showed increased production of IL-8, peaking at 2 dpi, compared to controls. Infection-mediated CD45-positive immune cell influx into the jejunal lamina propria peaked at 7 dpi, when epithelial damage was largely resolved. Activation of NF-κB appears to be a key early event in the innate response of the unprimed porcine immune system challenged with C. suis. This results in an acute phase, coinciding with the most severe clinical symptoms, diarrhea and weight loss. Immune cells recruited shortly after infection remain present in the lamina propria during the recovery phase, which is characterized by reduced chlamydial shedding and restored intestinal epithelium integrity.

Empowering Maasai women behind the camera: Photovoice as a tool for trachoma control

BACKGROUND

Photovoice is a method used to help engage community members to understand local realities and promote social change. Photovoice uses cameras in the hands of participants as a tool to visually document a specified topic. Photos taken by participants allow for reflection and stimulate dialog on an issue to ideally lead to social change. Trachoma, hyperendemic in Maasai communities in Northern Tanzania, is the commonest infectious cause of blindness worldwide, caused by chlamydia trachomatis. The bacterial infection commonly occurs in childhood and over many years repeated infections leads to inflammation and scarring of the eyelid. Often as adults this leads to the upper eyelid turning inward and eyelashes scratching the eye, resulting in pain and eventually blindness. We used photovoice as a tool for Maasai women to share their lived experiences of educating peers on trachoma and ultimately empowering women in this society.

METHODS

This public engagement intervention was conducted September thru October 2017. We held a workshop on trachoma control for 20 Maasai women including use of photovoice method. Women were asked to disseminate information from the trachoma control workshop to their community and to capture their experiences using disposable cameras. Five weeks post-workshop we facilitated a discussion and women displayed photos of the successes and challenges they encountered as advocates for trachoma control in their community.

INTERVENTION OUTCOMES

It was observed throughout the process and at the photo discussion meeting, that women articulated empowerment by this experience; as educators, agents of change and a source of valued information.

CONCLUSION

Photovoice should be considered for future interventions as a communication tool on health issues and to empower women to be ambassadors for health promotion.

Progress towards an inducible, replication-proficient transposon delivery vector for Chlamydia trachomatis

Background Genetic systems have been developed for Chlamydia but the extremely low transformation frequency remains a significant bottleneck.  Our goal is to develop a self-replicating transposon delivery vector for C. trachomatis which can be expanded prior to transposase induction. Methods We made E. coli/ C. trachomatis shuttle vectors bearing the Himar1 C9  transposase under control of the tet promoter and a novel rearrangement of the Himar1 transposon with the β-lactamase gene.  Activity of the transposase was monitored by immunoblot and by DNA sequencing. Results We constructed pSW2-mCh-C9, a C. trachomatis plasmid designed to act as a self-replicating vector carrying both the Himar1 C9  transposase under tet promoter control and its transposon.  However, we were unable to recover this plasmid in C. trachomatis following multiple attempts at transformation. Therefore, we assembled two new deletion plasmids pSW2-mCh-C9-ΔTpon carrying only the Himar1 C9  transposase (under tet promoter control) and a sister vector (same sequence backbone) pSW2-mCh-C9-ΔTpase carrying its cognate transposon.  We demonstrated that the biological components that make up both pSW2-mCh-C9-ΔTpon and pSW2-mCh-C9-ΔTpase are active in E. coli.  Both these plasmids could be independently recovered in C. trachomatis. We attempted to perform lateral gene transfer by transformation and mixed infection with C. trachomatis strains bearing pSW2-mCh-C9-ΔTpon and pSW2-RSGFP-Tpon (a green fluorescent version of pSW2-mCh-C9-ΔTpase).  Despite success in achieving mixed infections, it was not possible to recover progeny bearing both versions of these plasmids. Conclusions We have designed a self-replicating plasmid vector pSW2-mCh-C9 for C. trachomatis carrying the Himar1 C9  transposase under tet promoter control.  Whilst this can be transformed into E. coli it cannot be recovered in C. trachomatis.  Based on selected deletions and phenotypic analyses we conclude that low level expression from the tet inducible promoter is responsible for premature transposition and hence plasmid loss early on in the transformation process.

World Health Organization High Priority Pathogens: Ophthalmic Disease Findings and Vision Health Perspectives

Recent Ebola epidemics, the ongoing COVID-19 pandemic, and emerging infectious disease threats have highlighted the importance of global infectious diseases and responses to public health emergencies. Ophthalmologists are essential health care workers who provide urgent and emergent vision care services during outbreaks and address the ocular consequences of epidemic and pandemic infectious diseases. In 2017, the World Health Organization (WHO) identified high priority pathogens likely to cause a future epidemic with the goal of guiding research and development to improve diagnostic tests, vaccines, and medicines. These measures were necessary to better inform and respond to public health emergencies. Given the ocular complications associated with emerging infectious diseases, there is a need to recognize the ophthalmic sequelae for future vision health preparedness for potential future outbreaks. The WHO High Priority pathogens list provides a roadmap for ophthalmologists and subspecialty providers that will guide strategic areas of research for clinical care and preparedness for future pandemic threats. This review summarizes these key viral pathogens, summarizes major systemic disease findings, and delineates relevant ocular complications of the WHO High Priority pathogens list, including Crimean-Congo hemorrhagic fever, Filovirus diseases (Ebola virus disease and Marburg hemorrhagic fever), human Coronaviruses, Lassa Fever, Nipah virus infection, Zika, and Rift Valley fever.

Facial cleanliness indicators by time of day: results of a cross-sectional trachoma prevalence survey in Senegal

BACKGROUND

The World Health Organization-recommended strategy for trachoma elimination as a public health problem is known by the acronym "SAFE", where "F" stands for facial cleanliness to reduce transmission of ocular Chlamydia trachomatis infection. Accurately and reliably measuring facial cleanliness is problematic. Various indicators for measuring an unclean face exist, however, the accuracy and reliability of these indicators is questionable and their relationship to face washing practices is poorly described.

METHODS

Clean face indicator (ocular or nasal discharge, flies on the face, and dirt on the face), trachoma clinical sign, and ocular C. trachomatis infection data were collected for 1613 children aged 0-9 years in 12 Senegalese villages as part of a cross-sectional trachoma prevalence study. Time of examination was recorded to the nearest half hour. A risk factor questionnaire containing Water, Sanitation and Hygiene (WASH) questions was administered to heads of compounds (households that shared a common doorway) and households (those who shared a common cooking pot).

RESULTS

WASH access and use were high, with 1457/1613 (90.3%) children living in households with access to a primary water source within 30 min. Despite it being reported that 1610/1613 (99.8%) children had their face washed at awakening, > 75% (37/47) of children had at least one unclean face indicator at the first examination time-slot of the day. The proportion of children with facial cleanliness indicators differed depending on the time the child was examined. Dirt on the face was more common, and ocular discharge less common, in children examined after 11:00 h than in children examined at 10:30 h and 11:00 h.

CONCLUSIONS

Given the high reported WASH access and use, the proportion of children with an unclean face indicator should have been low at the beginning of the day. This was not observed, explained either by: the facial indicators not being reliable measures of face washing; eye discharge, nose discharge or dirt rapidly re-accumulated after face washing in children in this population at the time of fieldwork; and/or responder bias to the risk factor questionnaire. A high proportion of children had unclean face indicators throughout the day, with certain indicators varying by time of day. A reliable, standardised, practical measure of face washing is needed, that reflects hygiene behaviour rather than environmental or cultural factors.

Effectiveness and safety of azithromycin 1.5% eye drops for mass treatment of active trachoma in a highly endemic district in Cameroon

Objective

To evaluate the effectiveness and safety of azithromycin 1.5% eye drops under field conditions to reduce active trachoma in a highly endemic district in Cameroon. This is a follow-up of an initial report published in 2010.

Methods and analysis

Three annual campaigns were performed in 2008, 2009 and 2010 to treat the population (~1 20 000 individuals) of the Kolofata Health District with topical azithromycin 1.5% (one drop in each eye, morning and evening for three consecutive days). The effectiveness of this intervention against active trachoma was assessed in children aged 1–9 years in cross-sectional studies prior to each mass treatment using a systematic sampling procedure (in 2008, 2009 and 2010) and then 1 year (2011) and 3 years (2013) after the last intervention among the villages with previously high active trachoma prevalence or never tested.

Results

The prevalence of trachomatous inflammation—follicular (TF) dropped from 24.0% (95% CI 20.7 to 27.5) before treatment to 2.8% (95% CI 2.2 to 3.7) 1 year after completion of the 3 year campaign. Trachomatous inflammation—intense was present in only 4 (0.2%) children 1 year after the third round of treatment. Three years after the last campaign, the surveillance survey among the most prevalent villages and villages never tested before showed a prevalence of 5.2% (95% CI 3.6 to 7.2) of active trachoma. Tolerance was excellent, with no report of treatment interruption, serious ocular or systemic adverse events.

Conclusion

Annual mass treatment with azithromycin eye drops was shown to be effective in reducing TF to a level ≤5% one year after a 3-round annual mass treatment in an endemic region at the district level.

Prevalence of trachoma and associated factors in the rural area of the department of Vaupés, Colombia

OBJECTIVES

The objectives of the study were to estimate the prevalence of different clinical signs of trachoma and identify possible factors associated with TF.

METHODOLOGY

Following the approval of the study protocol by the ethics committee, a cross-sectional study was conducted in Vaupés, a department of the Colombian Amazon, between the years 2012 and 2013 in two districts. Based on the records obtained from a standardized format for the clinical evaluation of the participants and the factors associated with follicular trachoma, an excel database was built and debugged, which was analyzed using IBM SPSS, Statistics Version 23 and Stata STATA (Version 14, 2015, StataCorp LLC, Texas, USA).

RESULTS

The records of 13,091 individuals was collected from 216 rural indigenous communities, of which 12,080 were examined (92.3%); 7,274 in the Western and 4,806 in the Eastern districts. A prevalence of trachomatous inflammation-follicular (TF) of 21.7% (n = 599; 95% CI 20.2-23.3) in the Western and 24.9% (n = 483; 95% CI 23.1-26.9) in the Eastern district was found in children aged 1 to 9 years. Regarding trachomatous trichiasis (TT), 77 cases were found, of which 14 belonged to the Western district (prevalence 0.3%, CI 95% 0.2-0.5) and 63 to the Eastern district (1.8%, CI 95% 1.4-2.4). Children aged between 1 to 9 years were significantly more likely to have TF when there was the presence of secretions on the face (OR: 3.2; 95% CI: 2.6-3.9).

CONCLUSIONS

Trachoma is a public health problem in Vaupés that requires the implementation of the SAFE strategy (S = Surgery, A = Antibiotics, F = Face Washing, E = Environment) in the Eastern and Western districts, for at least 3 consecutive years, in accordance with WHO recommendations.

Relation of Chlamydia trachomatis infections to ectopic pregnancy: A meta-analysis and systematic review

BACKGROUND

In a multitude of previous studies, Chlamydia trachomatis (CT) plays an important role in the occurrence of ectopic pregnancy (EP). However, the predictive value of CT infections in the occurrence of EP has not been estimated worldwide. We thus evaluated, by means of a meta-analysis, the current status of the association between CT infections with EP and the potential predictive value of CT infections in EP.

METHODS

We evaluated studies performed between the database construction time and August 2018 published in PubMed, the Cochrane Library, EMBASE, and the Web of Science (SCI). The relationship between CT and EP was calculated based upon the predetermined entry criteria for control group selection and the original data. The related articles were analyzed using a random-effects model, and the heterogeneity of the studies was assessed using the I index. Data were analyzed with the STATA 12.0 software.

RESULTS

Twenty-five studies that recruited 11960 patients were included in the present meta-analysis, and the relation of CT infections with EP were assessed. The association between CT infections and EP risk showed an odds ratio (OR) of 3.03, with a 95% confidence interval (CI) of 2.37 to 3.89. Our results showed that there was a statistically significant difference between the intervention and control groups. The prevalence of CT infections in EP was then calculated by a subgroup analysis: African (OR, 2.22; 95% CI, 1.14-4.31), European (OR, 3.16; 95% CI, 2.10-4.47), North American (OR, 3.07; 95% CI, 1.78-5.31), and Asian (OR, 3.39; 95% CI, 1.95-5.90).

CONCLUSIONS

From the results of numerous studies conducted on different continents, this meta-analysis showed a clear association between EP and prior CT infections, that is, CT infections increase the risk of EP occurrence.

Perceptions and practices of community members relating to trachoma in Africa: a qualitative systematic review protocol

OBJECTIVE

The objective of this systematic review is to synthesize and present the best available evidence on community perceptions and practices relating to trachoma in Africa.

INTRODUCTION

Globally, trachoma is the leading cause of blindness and is responsible for about 1.4% of all cases of blindness. The African continent is the worst affected, with about 1.9 million cases of trichiasis (61%). While interventions are currently being implemented to combat the disease in Africa, very little is known by decision makers about community perceptions and practices relating to trachoma, which may hinder successful implementation.

INCLUSION CRITERIA

Studies with participants, regardless of their health status, gender, religion and ethnicity, aged 14 and over conducted in any African country, will be considered. Studies on Africans, conducted out of the continent and those involving healthcare professionals, will not be included in this review.

METHODS

Qualitative studies, published in English from 1996 onwards. will be considered. Databases to be searched will include, but not be limited to: PubMed, CINAHL, Embase and PsycINFO. Study selection, critical appraisal and data extraction will be conducted by two independent reviewers, using the appropriate JBI methodology and any disagreement will be resolved by discussion or with a third reviewer. Qualitative findings will be synthesized using the appropriate JBI methodology, following the meta-aggregation approach. Where textual pooling is not possible, the findings will be presented in narrative form. The ConQual approach will be used to grade synthesized findings, and these will be presented in a Summary of Findings.

Selecting behaviour change priorities for trachoma 'F' and 'E' interventions: A formative research study in Oromia, Ethiopia

BACKGROUND

Trachoma is the leading infectious cause of blindness. However, little is known about the behavioural and environmental determinants of transmission of the causative organism, Chlamydia trachomatis. We conducted formative research in a trachoma hyper-endemic area of Ethiopia to explore the behaviours which are likely to contribute to trachoma transmission and map their determinants.

METHODOLOGY/PRINCIPAL FINDINGS

Data on water use, hygiene, defecation, and sleeping arrangements were collected from five communities during the dry and rainy seasons in 2016. Data collection involved direct observation in households (n = 20), interviews with caregivers (n = 20) and focus group discussions (n = 11). Although several behaviours that likely contribute to trachoma transmission were identified, no single behaviour stood out as the dominant contributor. Hygiene practices reflected high levels of poverty and water scarcity. Face washing and soap use varied within and between households, and were associated with other factors such as school attendance. Children's faces were rarely wiped to remove nasal or ocular discharge, which was not perceived to be socially undesirable. Bathing and laundry were performed infrequently due to the amount of time and water required. Open defecation was a normative practice, particularly for young children. Latrines, when present, were poorly constructed, maintained and used. Young children and parents slept closely together and shared bedding that was infrequently washed.

CONCLUSIONS/SIGNIFICANCE

Existing norms and enabling factors in this context favour the development of interventions to improve facial cleanliness as more feasible than those that reduce unsafe faeces disposal. Interventions to increase the frequency of bathing and laundry may also be infeasible unless water availability within the home is improved.

Factors shaping the implementation of the SAFE strategy for trachoma using the Consolidated Framework for Implementation Research: a systematic review

Background: The SAFE strategy (surgery for trichiasis, antibiotics for active infection, facial cleanliness and environmental improvement) is the World Health Organization (WHO) recommended guideline for the elimination of blindness by trachoma by the year 2020.

Objective: While evaluations on the implementation of the SAFE strategy have been done, systematic reviews on the factors that have shaped implementation are lacking. This review sought to identify these factors.

Methods: We searched PUBMED, Google Scholar, CINAHL and Cochrane Collaboration to identify studies that had implemented SAFE interventions. The Consolidated Framework for Implementation Research (CFIR) guided development of the data extraction guide and data analysis.

Results: One hundred and thirty-seven studies were identified and only 10 papers fulfilled the eligibility criteria. Characteristics of the innovation – such as adaptation of the SAFE interventions to suit the setting and observability of positive health outcomes from pilots – increased local adoption. Characteristics of outer setting – which included strong multisectoral collaboration – were found to enhance implementation through the provision of resources necessary for programme activities. When community needs and resources were unaccounted for there was poor compatibility with local settings. Characteristics of the inner setting – such as poor staffing, high labour turnovers and lack of ongoing training – affected health workers’ implementation behaviour. Implementation climate within provider organisations was shaped by availability of resources. Characteristics of individuals – which included low knowledge levels – affected the acceptability of SAFE programmes; however, early adopters could be used as change agents. Finally, the use of engagement strategies tailored towards promoting community participation and stakeholder involvement during the implementation process facilitated adoption process.

Conclusion: We found CFIR to be a robust framework capable of identifying different implementation determinants in low resource settings. However, there is a need for more research on the organisational, provider and implementation process related factors for trachoma as most studies focused on the outer setting.

Burden of disease from inadequate water, sanitation and hygiene for selected adverse health outcomes: An updated analysis with a focus on low- and middle-income countries

BACKGROUND

To develop updated estimates in response to new exposure and exposure-response data of the burden of diarrhoea, respiratory infections, malnutrition, schistosomiasis, malaria, soil-transmitted helminth infections and trachoma from exposure to inadequate drinking-water, sanitation and hygiene behaviours (WASH) with a focus on low- and middle-income countries.

METHODS

For each of the analysed diseases, exposure levels with both sufficient global exposure data for 2016 and a matching exposure-response relationship were combined into population-attributable fractions. Attributable deaths and disability-adjusted life years (DALYs) were estimated for each disease and, for most of the diseases, by country, age and sex group separately for inadequate water, sanitation and hygiene behaviours and for the cluster of risk factors. Uncertainty estimates were computed on the basis of uncertainty surrounding exposure estimates and relative risks.

FINDINGS

An estimated 829,000 WASH-attributable deaths and 49.8 million DALYs occurred from diarrhoeal diseases in 2016, equivalent to 60% of all diarrhoeal deaths. In children under 5 years, 297,000 WASH-attributable diarrhoea deaths occurred, representing 5.3% of all deaths in this age group. If the global disease burden from different diseases and several counterfactual exposure distributions was combined it would amount to 1.6 million deaths, representing 2.8% of all deaths, and 104.6 million DALYs in 2016.

CONCLUSIONS

Despite recent declines in attributable mortality, inadequate WASH remains an important determinant of global disease burden, especially among young children. These estimates contribute to global monitoring such as for the Sustainable Development Goal indicator on mortality from inadequate WASH.

Knowledge, perceptions and experiences of trachoma among Maasai in Tanzania: Implications for prevention and control

BACKGROUND

The Alliance for the Global Elimination of Trachoma has set the target for eliminating trachoma as a public health problem by 2020. However, challenges remain, including socio-cultural issues. Districts in Northern Tanzania, predominantly inhabited by the Maasai ethnic group, remain endemic for trachoma. We explored socio-cultural factors that may impact the elimination of trachoma.

METHODS/FINDINGS

This study was nested within a larger ethnographic study of trachoma among Maasai in Northern Tanzania. We used stratified random sampling and semi-structured interviews to examine knowledge and understanding. Interviews were conducted and recorded in Maa, by a native Maa speaking trained interviewer. Transcripts were translated into English. A framework method for a content analysis was used. There was awareness of trachoma and basic symptoms. Yet understanding of etiology and prevention was poor. Trachoma was attributed to pollen, dust, and smoke. Water was recognized as beneficial, but seen as treatment and not prevention. Traditional medicines were most often used for treating conjunctival inflammation, with the most common being a rough leaf used to scratch the inside of the eyelid until it bleeds. Knowledge of mass drug administration (MDA) was inconsistent, although many thought it helped the community, but it was perceived as only for children and the sick. Many participants reported not taking azithromycin and some had no recollection of MDA six months earlier. There was little connection between childhood infection, trichiasis and related blindness. Trichiasis was often seen as a problem of old women, and treated locally by epilation.

CONCLUSION/SIGNIFICANCE

Understanding indigenous knowledge may help guide control programs, tailor them to local contexts, address local beliefs and dispel misunderstandings. There is an essential need to understand the social, cultural and political context of the target community to deliver effective programs. Despite limited knowledge, the community recognized trachoma as a public health problem. Results have implications for disease control programs in other marginalized communities.

Prevalence of Trachoma in Senegal: Results of Baseline Surveys in 17 Districts

Purpose: Senegal is endemic for trachoma, an infectious and potentially blinding eye disease. To complete the country’s district-level baseline map of trachoma, we conducted population-based surveys in 17 health districts that were suspected-endemic but had yet to be surveyed.

Methods: We randomly selected 30 clusters (villages) per district and 30 households per village, and estimated the district-level prevalences of trachomatous inflammation—follicular (TF) in children aged 1–9 years, and trichiasis in persons aged ≥15 years. Data on household-level water, sanitation, and hygiene variables were also collected. Global Trachoma Mapping Project methods were followed in training, fieldwork, and data handling.

Results: 25,704 children aged 1–9 years and 30,345 adults aged 15 years and above were examined. In children aged 1–9 years, the prevalence of TF was <5% in all 17 districts, with the exception of Saint-Louis (5.1%, 95% CI 3.2–7.5). Trichiasis prevalence in participants aged 15 years and above ranged by district from 0%–1.1% (95% CI 0.7–1.5), with 9 districts having trichiasis prevalences above the elimination threshold of 0.2%. Trichiasis was seen to be significantly less frequent in males than in females (0.17% [95% CI 0.12–0.24] versus 0.49% [95% CI 0.38–0.61], p < 0.001). The prevalence of trichiasis rose steeply with age; 62% of cases were observed in people aged 55 years or above.

Conclusions: Active trachoma is not a public health problem in 16 of the 17 surveyed districts, and implementation of the full Surgery (S) – Antibiotics (A) – Facial cleanliness (F) – Environmental improvement (E) strategy is not a programmatic priority. Increased provision of trichiasis surgery is warranted in nine districts.

Non-Chlamydial Bacterial Infection and Progression of Conjunctival Scarring in Trachoma

Purpose

The purpose of this study was to assess whether non-chlamydial bacterial infection is associated with progression of trachomatous scarring in adults.

Methods

This was a cohort study involving 800 participants in northern Tanzania who underwent clinical examination, photography, and conjunctival swab collection for microbiology over a 24-month period. Samples for microbiology were inoculated onto blood and chocolate agar, and Chlamydia trachomatis was detected by PCR. Progression was determined by comparison of baseline to 24-month photographs.

Results

C. trachomatis was detected in only four participants at baseline. At 24 months, 617 participants (77.1%) were followed up. Of those seen at 24 months, 452 could be reliably assessed. Definite scarring progression (progressors) was seen in 345 (55.9%); there was no progression (nonprogressors) in 107 (17.3%). Using combined baseline and 12-month microbiology results, progressors had significantly higher levels of commensal and pathogenic bacterial organisms detected compared with nonprogressors. After adjusting for age, baseline scarring, and ethnicity, there was weak evidence (P = 0.07) that the bacteria category was associated with scarring progression (commensal organisms only: odds ratio [OR] = 1.61; 95% confidence interval [CI]: 0.90 to 2.89; pathogenic organisms either with or without commensal: OR = 2.39; 95% CI: 1.10 to 5.16).

Conclusion

The findings were consistent with the possibility that trachomatous scarring in adults is associated with the presence of non-chlamydial bacterial organisms, particularly pathogenic organisms. C. trachomatis was detected very infrequently and may not be an important factor in the pathogenesis of scarring progression in adults. This has implications for trachoma control programs, which largely concentrate on reducing C. trachomatis levels and transmission.

Optimising age adjustment of trichiasis prevalence estimates using data from 162 standardised surveys from seven regions of Ethiopia

PURPOSE

The prevalence of trichiasis is higher in females and increases markedly with age. Surveys carried out in the daytime, particularly in developing countries, are prone to find older individuals and females at home at the time of the survey. Population-level trichiasis estimates should adjust sample proportions to reflect the demographic breakdown of the population, although the most accurate method of doing this is unclear.

METHODS

Having obtained data from 162 surveys carried out in Ethiopia as part of the Global Trachoma Mapping Project from 2012 to 2015, we used internal validation with both Brier and Logarithmic forecast scoring to test stratification models to identify those models with the highest predictive accuracy. Selection of partitions was undertaken by both simple random sampling (SRS) and cluster sampling (CS) over 8192 selections.

RESULTS

A total of 4529 (1.9%) cases of trichiasis were identified from 241,139 individuals aged ≥15 years from a total of 4210 kebeles and 122,090 households visited. Overall, the binning method using 5-year bands from age 15 to 69 years, with coarser binning in 20-year age-bands above this age, provided the best predictive accuracy, in both SRS and CS methodologies and for both the Brier and Logarithmic scoring rules.

CONCLUSION

The greatest predictive accuracy for trichiasis estimates was found by adjusting for sex and in 5-year age-bands from the age of 15 to 69 years and in 20-year age-bands in those aged 70 years and greater. Trichiasis surveys attempting to make population-level inferences should use this method to optimise surgery backlog estimates.

A FACS-Based Genome-wide CRISPR Screen Reveals a Requirement for COPI in Chlamydia trachomatis Invasion

The invasion of Chlamydia trachomatis, an obligate intracellular bacterium, into epithelial cells is driven by a complex interplay of host and bacterial factors. To comprehensively define the host genes required for pathogen invasion, we undertook a fluorescence-activated cell sorting (FACS)-based CRISPR screen in human cells. A genome-wide loss-of-function library was infected with fluorescent C. trachomatis and then sorted to enrich for invasion-deficient mutants. The screen identified heparan sulfate, a known pathogen receptor, as well as coatomer complex I (COPI). We found that COPI, through a previously unappreciated role, promotes heparan sulfate cell surface presentation, thereby facilitating C. trachomatis attachment. The heparan sulfate defect does not fully account for the resistance of COPI mutants. COPI also promotes the activity of the pathogen's type III secretion system. Together, our findings establish the requirement for COPI in C. trachomatis invasion and the utility of FACS-based CRISPR screening for the elucidation of host factors required for pathogen invasion.

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FACS-based CRISPR screen to identify host factors required for C. trachomatis invasion

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Candidate genes comprise heparan sulfate biosynthesis, actin remodeling, and COPI

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COPI regulates heparan sulfate cell surface presentation and C. trachomatis attachment

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COPI is also required for efficient C. trachomatis T3SS translocation

The History of Trachoma and Current Prevalence (Spotlight on Iran): A Review Article

BACKGROUND

Trachoma as a common cause of infectious blindness is caused by Chlamydia trachomatis. This study aimed to review the available data from variety of sources and provide an overview of the epidemiological situation of Trachoma in Iran focused on the past seventy five years.

METHODS

A literature search of English and Farsi articles regarding trachoma in Iran from the electronic databases and paper documents was performed. Original articles, case reports and letters were included.

RESULTS

By the early and mid-20^th century, trachoma was widely endemic with the prevalence rate of more than 60% in Iran. Currently, trachoma prevalence is significantly lower than in the past and the elimination of trachoma is achievable in the near future. The decline in active disease is mainly attributed to improvement of socio-economic situation and personal and environmental hygiene rather than targeted interventions for epidemic control.

CONCLUSION

Elimination of trachoma in Iran is achievable. However, trachoma prevalence estimation is required to be interpreted with some caution. Uncertainty around these estimates is partly because of the mismatch between the presence of infection and clinical findings.

An impact evaluation of two rounds of mass drug administration on the prevalence of active trachoma: A clustered cross sectional survey

INTRODUCTION

We investigated the impact of two round of mass drug administration on trachoma prevalence in Plateau and Nasarawa States of Nigeria. The mass drug administration was conducted as a component of the SAFE Strategy, a combination of interventions recommended for the global elimination of blinding trachoma.

METHODS

The study consisted of a two-stage cross-sectional clustered sample survey in which 3990 people from 793 households were screened for clinical signs of trachoma.

RESULTS

Of the total 3990 people examined, 1530 were children, of which 808 (53%) were boys and 704 (47%) were girls. The impact of intervention as measured by the changes in overall prevalence of follicular trachoma were as follows: At baseline the overall prevalence of follicular trachoma among children 1-9 years of age was 6.4%, 95% CI [5.8, 7.0]; the overall prevalence of trachomatous trichiasis in the total population was 0.20%, 95% CI [0.16, 0.25]. At follow up, the overall prevalence of follicular trachoma among children 1-9 years of age was 3.4%, 95% CI [1.9, 4.9]; the overall prevalence of trachomatous trichiasis in the total population was 0.20%, 95% CI [0.00, 0.05]. The highest statistically significant reduction (96%) in follicular trachoma prevalence was observed in Doma Local Government Area of Nasarawa State from baseline prevalence of 13.6%, 95% CI [9.7, 17.5] to follow-up prevalence of 0.5%, 95% CI [0.0, 1.5] and the lowest reduction (58%) in follicular trachoma prevalence was observed in Langtang North Local Government Area of Plateau State from baseline prevalence of 15.8%, 95% CI [9.3, 22.3] to 6.6%, 95% CI [1.6, 11.6], (p<0.05).

CONCLUSION

A significant reduction in the overall prevalence of follicular trachoma was achieved after two rounds of mass drug administration. In the absence of significant activities pertaining to facial cleanliness and environmental sanitation components of the SAFE strategy in the intervention areas, the observed deep reductions in prevalence could mainly be attributed to mass drug administration. Therefore, two rounds of mass azithromycin administration may be as effective as guideline-recommended three or more rounds in reducing active trachoma prevalence but findings should be replicated in more robustly designed studies.

Mass azithromycin distribution for hyperendemic trachoma following a cluster-randomized trial: A continuation study of randomly reassigned subclusters (TANA II)

BACKGROUND

The World Health Organization recommends annual mass azithromycin administration in communities with at least 10% prevalence of trachomatous inflammation-follicular (TF) in children, with further treatment depending on reassessment after 3-5 years. However, the effect of stopping mass azithromycin distribution after multiple rounds of treatment is not well understood. Here, we report the results of a cluster-randomized trial where communities that had received 4 years of treatments were then randomized to continuation or discontinuation of treatment.

METHODS AND FINDINGS

In all, 48 communities with 3,938 children aged 0-9 years at baseline in northern Ethiopia had received 4 years of annual or twice yearly mass azithromycin distribution as part of the TANA I trial. We randomized these communities to either continuation or discontinuation of treatment. Individuals in the communities in the continuation arm were offered either annual or twice yearly distribution of a single directly observed dose of oral azithromycin. The primary outcome was community prevalence of ocular chlamydial infection in a random sample of children aged 0-9 years, 36 months after baseline. We also assessed the change from baseline to 36 months in ocular chlamydia prevalence within each arm. We compared 36-month ocular chlamydia prevalence in communities randomized to continuation versus discontinuation in a model adjusting for baseline ocular chlamydia prevalence. A secondary prespecified analysis assessed the rate of change over time in ocular chlamydia prevalence between arms. In the continuation arm, mean antibiotic coverage was greater than 90% at all time points. In the discontinuation arm, the mean prevalence of infection in children aged 0-9 years increased from 8.3% (95% CI 4.2% to 12.4%) at 0 months to 14.7% (95% CI 8.7% to 20.8%, P = 0.04) at 36 months. Ocular chlamydia prevalence in communities where mass azithromycin distribution was continued was 7.2% (95% CI 3.3% to 11.0%) at baseline and 6.6% (95% CI 1.1% to 12.0%, P = 0.64) at 36 months. The 36-month prevalence of ocular chlamydia was significantly lower in communities continuing treatment compared with those discontinuing treatment (P = 0.03). Limitations of the study include uncertain generalizability outside of trachoma hyperendemic regions.

CONCLUSIONS

In this study, ocular chlamydia infection rebounded after 4 years of periodic mass azithromycin distribution. Continued distributions did not completely eliminate infection in all communities or meet WHO control goals, although they did prevent resurgence.

TRIAL REGISTRATION

This study was prospectively registered at clinicaltrials.gov (clinicaltrials.gov NCT01202331).

Orchestration of the mammalian host cell glucose transporter proteins-1 and 3 by Chlamydia contributes to intracellular growth and infectivity

Chlamydia are gram-negative obligate intracellular bacteria that replicate within a discrete cellular vacuole, called an inclusion. Although it is known that Chlamydia require essential nutrients from host cells to support their intracellular growth, the molecular mechanisms for acquiring these macromolecules remain uncharacterized. In the present study, it was found that the expression of mammalian cell glucose transporter proteins 1 (GLUT1) and glucose transporter proteins 3 (GLUT3) were up-regulated during chlamydial infection. Up-regulation was dependent on bacterial protein synthesis and Chlamydia-induced MAPK kinase activation. GLUT1, but not GLUT3, was observed in close proximity to the inclusion membrane throughout the chlamydial developmental cycle. The proximity of GLUT1 to the inclusion was dependent on a brefeldin A-sensitive pathway. Knockdown of GLUT1 and GLUT3 with specific siRNA significantly impaired chlamydial development and infectivity. It was discovered that the GLUT1 protein was stabilized during infection by inhibition of host-dependent ubiquitination of GLUT1, and this effect was associated with the chlamydial deubiquitinase effector protein CT868. This report demonstrates that Chlamydia exploits host-derived transporter proteins altering their expression, turnover and localization. Consequently, host cell transporter proteins are manipulated during infection as a transport system to fulfill the carbon source requirements for Chlamydia.

Trachoma in Yunnan province of southwestern China: findings from trachoma rapid assessment

BACKGROUND

To understand the situation of active trachoma among children aged 6 to 8 years old and scarring trachoma among those aged 15 and over in Yunnan Province, South-western China.

METHODS

A rapid assessment of trachoma was conducted to determine the presence or absence of trachoma in Yunnan. Through risk assessment, 9 sites in 8 suspected trachoma epidemic counties were selected. Trachoma Rapid Assessment was conducted in these areas afterwards. Within each sites, 50 students from grade one in local primary school and adults aged 15 and above with suspected scarring trachoma were examined by survey teams.

RESULTS

A total of 450 children aged 6-8 years and 160 adults aged 15 and above were screened in 9 sites of 8 counties. Only 1 case of active trachoma was found. Detection rate of active trachoma in children was 0.2%(1/450) in all sites and 2% (1/50)in Pingbian County. Out of 150 adults only 1 case of TT and 1 case of CO were found in all the highest at risk communities. People with scarring trachoma were aged over 60 years.

CONCLUSIONS

The active trachoma was rarely seen and trachoma is unlikely to be a significant public health problem in Yunnan Province, South-western China.

Population-based analysis of ocular Chlamydia trachomatis in trachoma-endemic West African communities identifies genomic markers of disease severity

BACKGROUND

Chlamydia trachomatis (Ct) is the most common infectious cause of blindness and bacterial sexually transmitted infection worldwide. Ct strain-specific differences in clinical trachoma suggest that genetic polymorphisms in Ct may contribute to the observed variability in severity of clinical disease.

METHODS

Using Ct whole genome sequences obtained directly from conjunctival swabs, we studied Ct genomic diversity and associations between Ct genetic polymorphisms with ocular localization and disease severity in a treatment-naïve trachoma-endemic population in Guinea-Bissau, West Africa.

RESULTS

All Ct sequences fall within the T2 ocular clade phylogenetically. This is consistent with the presence of the characteristic deletion in trpA resulting in a truncated non-functional protein and the ocular tyrosine repeat regions present in tarP associated with ocular tissue localization. We have identified 21 Ct non-synonymous single nucleotide polymorphisms (SNPs) associated with ocular localization, including SNPs within pmpD (odds ratio, OR = 4.07, p* = 0.001) and tarP (OR = 0.34, p* = 0.009). Eight synonymous SNPs associated with disease severity were found in yjfH (rlmB) (OR = 0.13, p* = 0.037), CTA0273 (OR = 0.12, p* = 0.027), trmD (OR = 0.12, p* = 0.032), CTA0744 (OR = 0.12, p* = 0.041), glgA (OR = 0.10, p* = 0.026), alaS (OR = 0.10, p* = 0.032), pmpE (OR = 0.08, p* = 0.001) and the intergenic region CTA0744-CTA0745 (OR = 0.13, p* = 0.043).

CONCLUSIONS

This study demonstrates the extent of genomic diversity within a naturally circulating population of ocular Ct and is the first to describe novel genomic associations with disease severity. These findings direct investigation of host-pathogen interactions that may be important in ocular Ct pathogenesis and disease transmission.

Coverage, social mobilization and challenges of mass Zithromax administration campaign in South and South East zones of Tigray, Northern Ethiopia: A cross sectional study

Background

The antibiotic treatment of people with trachoma helps to prevent transmission the disease in a community. Currently, Zithromax is the drug recommended for mass drug administration (MDA). MDA should be carried out annually for three to five years in trachoma endemic areas. Coverage survey is essential to track progress towards program goals and to identify communities with poor coverage in order to permit timely and appropriate actions. We assessed mass Zithromax administration coverage, social mobilization and campaign challenges in south and southeast zones of Tigray, Ethiopia.

Method

We conducted a survey in community in Southern and South East zones of Tigray region from August 15 to August 31, 2016. The survey included nine Woredas. It was supported by qualitative methods. A total of 3741 individuals were enrolled from 933 households using multistage sampling. We used structured questionnaire. In-depth interview and focus group discussion were also applied. Descriptive statistics was performed using SPSS version 20.We thematically analyzed the qualitative data using Atlas 7.

Result

The overall coverage of Zithromax MDA was 93.3%. It ranges from 90.0% in Seharti Samre to 97.9% in Endamokoni. The coverage was 93.4% for males and 93.1% for females. A higher proportion (98.3%) of children aged 5 to 15 years and 409 (87.8%) under five children took Zithromax. The coverage was 94% in rural and 91.2% in urban. Women development army (43.3%) and health extension workers (32.5%) were the main source of information. Frequent occurrence of drug side effects, rumors, lack of community and leaders’ engagement in the campaign, fasting, shortage of human power and short term unavailability of supplies were barriers during the campaign.

Conclusion

The Zithromax MDA coverage in the study zones was higher than the minimum WHO set criteria of 80%. There was a wide difference in coverage among Woredas and Kebeles. The MDA coverage was lower in urban than rural. Misconceptions and poor mobilization were common challenges. Thus, proper planning, community mobilization and uniform training will need to be done ahead of the campaign in the future.

Ethiopia has the world's highest burden of trachoma. The disease causes significant blindness and visual impairment, particularly in poorer communities. To prevent the transmission of active trachoma, mass administration of Zithromax is given every year, which is implemented for consecutive three to five years in endemic and hyper endemic areas of the country. We have shown that the mass administration coverage of Zithromax, in 2016, was greater than 90% in the South and Southeastern zones of Tigray, Ethiopia. However, it was accompanied by a number of program challenges and social barriers.Women development armies and health extension workers were key players in community mobilization and drug provision, respectively.

Prevalence of trachoma in school children in the Marajó Archipelago, Brazilian Amazon, and the impact of the introduction of educational and preventive measures on the disease over eight years

Trachoma is the leading infectious cause of blindness in the world and is associated with precarious living conditions in developing countries. The aim of the present study was to evaluate the prevalence of trachoma in three municipalities of the Marajó Archipelago, located in the state of Pará, Brazil. In 2008, 2,054 schoolchildren from the public primary school system of the urban area of the region and their communicants were clinically examined; in 2016, 1,502 schoolchildren were examined. The positive cases seen during the clinical evaluation were confirmed by direct immunofluorescence (DIF) laboratory tests. The presence of antibodies against the genus Chlamydia was evaluated by indirect immunofluorescence (IIF), and the serotypes were determined by microimmunofluorescence (MIF). In 2008, the prevalence of trachoma among schoolchildren was 3.4% (69 cases) and it was more frequent in children between six and nine years of age and in females; among the communicants, a prevalence of 16.5% was observed. In 2016, three cases of trachoma were diagnosed (prevalence of 0.2%), found only in the municipality of Soure. The results of the present study showed that in 2008, trachoma had a low prevalence (3.4%) among schoolchildren in the urban area of Marajó Archipelago; eight years after the first evaluation and the introduction of control and prevention measures (SAFE strategy), there was a drastic reduction in the number of cases (0.2%), demonstrating the need for constant monitoring and effective measures for the elimination of trachoma.

Trachoma is one of the main neglected infectious diseases and carry a considerable burden to human health as a consequence of the clinical severity of the disease which may evolve to blindness. The lack of hygiene, education and other indicators of low social and economic markers occurring in developing and underdeveloped countries favour the spread of Chlamydia trachomatis, the bacterium causing trachoma. Although there is an easy, cheap and available treatment, reinfections are common and transmission is a consequence of bad hygienic habits and the various serotypes of the bacterium. The Marajó territory, in the North of the Amazon region of Brazil, is a large area with an ill educated, poor population, with almost no access to health resources and with almost no chance of transportation to major urban centers. Trachoma was detected a long time ago in the island and now, for the first time, a clear effort was produced during an eight year period in order to improve health hygienic habits among children and their relatives. The number of new cases following an initial diagnosis, was significantly reduced by the application of the WHO SAFE (Surgery, Antibiotics, Facial hygiene and Education for better habits) strategy.

Sanitation and water supply coverage thresholds associated with active trachoma: Modeling cross-sectional data from 13 countries

BACKGROUND

Facial cleanliness and sanitation are postulated to reduce trachoma transmission, but there are no previous data on community-level herd protection thresholds. We characterize associations between active trachoma, access to improved sanitation facilities, and access to improved water sources for the purpose of face washing, with the aim of estimating community-level or herd protection thresholds.

METHODS AND FINDINGS

We used cluster-sampled Global Trachoma Mapping Project data on 884,850 children aged 1-9 years from 354,990 households in 13 countries. We employed multivariable mixed-effects modified Poisson regression models to assess the relationships between water and sanitation coverage and trachomatous inflammation-follicular (TF). We observed lower TF prevalence among those with household-level access to improved sanitation (prevalence ratio, PR = 0.87; 95%CI: 0.83-0.91), and household-level access to an improved washing water source in the residence/yard (PR = 0.81; 95%CI: 0.75-0.88). Controlling for household-level water and latrine access, we found evidence of community-level protection against TF for children living in communities with high sanitation coverage (PR80-90% = 0.87; 95%CI: 0.73-1.02; PR90-100% = 0.76; 95%CI: 0.67-0.85). Community sanitation coverage levels greater than 80% were associated with herd protection against TF (PR = 0.77; 95%CI: 0.62-0.97)-that is, lower TF in individuals whose households lacked individual sanitation but who lived in communities with high sanitation coverage. For community-level water coverage, there was no apparent threshold, although we observed lower TF among several of the higher deciles of community-level water coverage.

CONCLUSIONS

Our study provides insights into the community water and sanitation coverage levels that might be required to best control trachoma. Our results suggest access to adequate water and sanitation can be important components in working towards the 2020 target of eliminating trachoma as a public health problem.

The impact of a single round of community mass treatment with azithromycin on disease severity and ocular Chlamydia trachomatis load in treatment-naïve trachoma-endemic island communities in West Africa

BACKGROUND

Trachoma, a neglected tropical disease, is caused by ocular infection with Chlamydia trachomatis (Ct). The World Health Organization (WHO) recommends three annual rounds of community mass drug treatment with azithromycin (MDA) if the prevalence of follicular trachoma in 1-9 year olds (TF_1-9) exceeds 10% at district level to achieve an elimination target of district-level TF_1-9 below 5% after. To evaluate this strategy in treatment-naïve trachoma-endemic island communities in Guinea Bissau, we conducted a cross-sectional population-based trachoma survey on four islands. The upper tarsal conjunctivae of each participant were clinically assessed for trachoma and conjunctival swabs were obtained (n = 1507). We used a droplet digital PCR assay to detect Ct infection and estimate bacterial load. We visited the same households during a second cross-sectional survey and repeated the ocular examination and obtained conjunctival swabs from these households one year after MDA (n = 1029).

RESULTS

Pre-MDA TF_1-9 was 22.0% (136/618). Overall Ct infection prevalence (CtI) was 18.6% (25.4% in 1-9 year olds). Post-MDA (estimated coverage 70%), TF_1-9 and CtI were significantly reduced (7.4% (29/394, P < 0.001) and 3.3% (34/1029, P < 0.001) (6.6% in 1-9 year olds, P < 0.001), respectively. Median ocular Ct load was reduced from 2038 to 384 copies/swab (P < 0.001). Following MDA cases of Ct infection were highly clustered (Moran's I 0.27, P < 0.001), with fewer clusters of Ct infection overall, fewer clusters of cases with high load infections and less severe disease.

CONCLUSIONS

Despite a significant reduction in the number of clusters of Ct infection, mean Ct load, disease severity and presence of clusters of cases of high load Ct infection suggesting the beginning of trachoma control in isolated island communities, following a single round of MDA we demonstrate that transmission is still ongoing. These detailed data are useful in understanding the epidemiology of ocular Ct infection in the context of MDA and the tools employed may have utility in determining trachoma elimination and surveillance activities in similar settings.