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

Purpose: Population-based prevalence surveys are essential for decision-making on interventions to achieve trachoma elimination as a public health problem. This paper outlines the methodologies of Tropical Data, which supports work to undertake those surveys.

Methods: Tropical Data is a consortium of partners that supports health ministries worldwide to conduct globally standardised prevalence surveys that conform to World Health Organization recommendations.

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.

HLA-A, -B, -C, -DPB1, -DQB1 and -DRB1 allele frequencies of North Tanzanian Maasai.

Locus-specific amplicon sequencing was used to HLA type 336 participants of Maasai ethnicity at the HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1 loci. Participants were recruited from three study villages in North Tanzania, for the purpose of investigating risk factors for trachomatous scarring in children. Other than HLA-A, all loci significantly deviated from Hardy-Weinberg equilibrium, possibly due to high relatedness between individuals: 238 individuals shared a house with at least one another participant.

The conjunctival microbiome before and after azithromycin mass drug administration for trachoma control in a cohort of Tanzanian children.

Background: Trachoma, caused by ocular infection with , is a neglected tropical disease that can lead to blinding pathology. Current trachoma control programmes have successfully used mass drug administration (MDA) with azithromycin to clear infection and reduce transmission, alongside promoting facial cleanliness for better personal hygiene and environmental improvement. In areas of low-trachoma endemicity, the relationship between infection and trachomatous disease weakens, and non-chlamydial bacteria have been associated with disease signs.

In vivo confocal microscopy and trachomatous conjunctival scarring: Predictors for clinical progression.

Importance: In vivo confocal microscopy (IVCM) provides high-resolution images of the ocular surface and has been validated in trachomatous conjunctival scarring.

Background: This study used IVCM to identify parameters associated with clinical scarring progression.

Design: Prospective cohort study.

Immunopathogenesis of Progressive Scarring Trachoma: Results of a 4-Year Longitudinal Study in Tanzanian Children.

Trachoma is initiated during childhood following repeated conjunctival infection with , which causes a chronic inflammatory response in some individuals that leads to scarring and in-turning of the eyelids in later life. There is currently no treatment to halt the progression of scarring trachoma due to an incomplete understanding of disease pathogenesis. A cohort study was performed in northern Tanzania in 616 children aged 6 to 10 years at enrollment.

Progression of scarring trachoma in Tanzanian children: A four-year cohort study.

Background: Trachoma is a progressive blinding disease initiated by infection of the conjunctiva with Chlamydia trachomatis. Repeated infections are thought to cause chronic inflammation, which drives scarring, leading to in-turning of the eyelids. The relationship between C.

Ocular immune responses, Chlamydia trachomatis infection and clinical signs of trachoma before and after azithromycin mass drug administration in a treatment naïve trachoma-endemic Tanzanian community.

Background: Trachoma, caused by Chlamydia trachomatis, remains the leading infectious cause of blindness worldwide. Persistence and progression of the resulting clinical disease appears to be an immunologically mediated process. Azithromycin, which is distributed at the community level for trachoma control, has immunomodulatory properties.

Epidemiology of trachoma and its implications for implementing the "SAFE" strategy in Somali Region, Ethiopia: results of 14 population-based prevalence surveys.

Purpose: Ethiopia is highly trachoma endemic. Baseline mapping was needed in Ethiopia's Somali Region to guide elimination efforts.

Methods: Cross-sectional community-based surveys were conducted in 34 suspected trachoma-endemic woredas, grouped as 14 evaluation units (EUs), using a standardised mapping methodology developed for the Global Trachoma Mapping Project.

Prevalence of Trachoma in 47 Administrative Districts of Zambia: Results of 32 Population-Based Prevalence Surveys.

Purpose: A number of previous administrative-district-level baseline trachoma prevalence estimates in Zambia required verification. We used methodologies and systems for trachoma surveys considered to represent international best practice in order to generate reliable estimates of the prevalence of trachoma.

Methods: Between March 2016 and July 2017, we undertook 32 population-based prevalence surveys covering 47 administrative districts.

The utility of serology for elimination surveillance of trachoma.

Robust surveillance methods are needed for trachoma control and recrudescence monitoring, but existing methods have limitations. Here, we analyse data from nine trachoma-endemic populations and provide operational thresholds for interpretation of serological data in low-transmission and post-elimination settings. Analyses with sero-catalytic and antibody acquisition models provide insights into transmission history within each population.

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.

Immunofibrogenic Gene Expression Patterns in Tanzanian Children with Ocular Infection, Active Trachoma and Scarring: Baseline Results of a 4-Year Longitudinal Study.

Trachoma, caused by , is the world's leading infectious cause of blindness and remains a significant public health problem. Much of trachomatous disease pathology is thought to be caused indirectly by host cellular and immune responses, however the immune response during active trachoma and how this initiates progressive scarring is not clearly understood. Defining protective vs.

Reduced-cost Chlamydia trachomatis-specific multiplex real-time PCR diagnostic assay evaluated for ocular swabs and use by trachoma research programmes.

Introduction: Trachoma, caused by the intracellular bacterium Chlamydia trachomatis (Ct), is the leading infectious cause of preventable blindness. Many commercial platforms are available that provide highly sensitive and specific detection of Ct DNA. However, the majority of these commercial platforms are inaccessible for population-level surveys in resource-limited settings typical to trachoma control programmes.

miRNAs that associate with conjunctival inflammation and ocular Chlamydia trachomatis infection do not predict progressive disease.

We previously showed that conjunctival miR-147b and miR-1285 were upregulated in Gambian adults with inflammatory scarring trachoma, and miR-155 and miR-184 expression was strongly associated with conjunctival inflammation and ocular Chlamydia trachomatis infection in children from Guinea-Bissau. We investigated whether the single or combined expression of miR-147b, miR-1285, miR-155 and miR-184 was able to identify individuals with increased risk of incident or progressive scarring trachoma. Conjunctival swab samples were collected from 506 children between the ages of 4 and 12 living in northern Tanzania.

Progress of Trachoma Mapping in Mainland Tanzania: Results of Baseline Surveys from 2012 to 2014.

Purpose: Following surveys in 2004-2006 in 50 high-risk districts of mainland Tanzania, trachoma was still suspected to be widespread elsewhere. We report on baseline surveys undertaken from 2012 to 2014.

Methods: A total of 31 districts were surveyed.

Baseline Trachoma Surveys in Kaskazini A and Micheweni Districts of Zanzibar: Results of Two Population-Based Prevalence Surveys Conducted with the Global Trachoma Mapping Project.

Purpose: Based on health care records and trachoma rapid assessments, trachoma was suspected to be endemic in Kaskazini A and Micheweni districts of Zanzibar. This study aimed to investigate the prevalence of trachomatous inflammation-follicular (TF), and trachomatous trichiasis (TT) in each of those districts.

Methods: The survey was undertaken in Kaskazini A and Micheweni districts on Unguja and Pemba Islands, respectively.

Differential frequency of NKG2C/KLRC2 deletion in distinct African populations and susceptibility to Trachoma: a new method for imputation of KLRC2 genotypes from SNP genotyping data.

NKG2C is an activating receptor that is preferentially expressed on natural killer (NK) cells. The gene encoding NKG2C (killer cell lectin-like receptor C2, KLRC2) is present at different copy numbers in the genomes of different individuals. Deletion at the NKG2C locus was investigated in a case-control study of 1522 individuals indigenous to East- and West-Africa and the association with the ocular Chlamydia trachomatis infection and its sequelae was explored.

Immunohistochemical Analysis of Scarring Trachoma Indicates Infiltration by Natural Killer and Undefined CD45 Negative Cells.

Introduction: The phenotype and function of immune cells infiltrating the conjunctiva in scarring trachoma have yet to be fully characterized. We assessed tissue morphology and immunophenotype of cellular infiltrates found in trachomatous scarring compared to control participants.

Methodology: Clinical assessments and conjunctival biopsy samples were obtained from 34 individuals with trachomatous scarring undergoing trichiasis surgery and 33 control subjects undergoing cataract or retinal detachment surgery.

Pathogenesis of progressive scarring trachoma in Ethiopia and Tanzania and its implications for disease control: two cohort studies.

Background: Trachoma causes blindness through a conjunctival scarring process initiated by ocular Chlamydia trachomatis infection; however, the rates, drivers and pathophysiological determinants are poorly understood. We investigated progressive scarring and its relationship to conjunctival infection, inflammation and transcript levels of cytokines and fibrogenic factors.

Methodology/principal Findings: We recruited two cohorts, one each in Ethiopia and Tanzania, of individuals with established trachomatous conjunctival scarring.

Serology for trachoma surveillance after cessation of mass drug administration.

Background: Trachoma, caused by Chlamydia trachomatis (Ct), is the leading infectious cause of blindness worldwide. Yearly azithromycin mass drug administration (MDA) plays a central role in efforts to eliminate blinding trachoma as a public health problem. Programmatic decision-making is currently based on the prevalence of the clinical sign "trachomatous inflammation-follicular" (TF) in children.

In vivo confocal microscopy and histopathology of the conjunctiva in trachomatous scarring and normal tissue: a systematic comparison.

Aim: To compare in vivo confocal microscopy (IVCM) with the histopathological examination of tissue and cellular changes in normal and diseased conjunctiva.

Methods: Participants underwent clinical examination and IVCM of the tarsal conjunctiva. A biopsy of the upper tarsal conjunctiva was collected and stained with tinctorial stains and by immunohistochemical staining for CD45 and CD83.