Trachomatous Inflammation-follicular Research Articles

The Impact of Image Quality and Trachomatous Inflammation on Using Photography for Trachoma Prevalence Surveys

PurposeGraded images can be used for trachoma prevalence surveys, but there is concern for mismatch between image and field grades of the upper tarsal conjunctiva. We aimed to determine if poor photograph quality and/or inflammation may contribute to differential grading of trachomatous inflammation—follicular (TF) between field and photograph graders.MethodsWe developed a simplified and expanded image quality grading tool. Agreement was assessed using kappa statistic. We included 5417 eyes with both field and image grades for TF. Eyes where the field and adjudicated photograph TF grades did not match were identified (mismatched) and assigned an image quality (IQ) score and a potential mismatch reason. We also assigned IQ scores to a stratified random sample of 60 eyes with matching field and photograph TF grades (matched).ResultsThere were 5240 eyes that had matching grades, whereas 177 eyes (3.3%) were mismatched. Overall quality was high, even in mismatched eyes. There was no difference in overall or specific IQ metrics between eyes with matching grades and eyes with mismatched grades (P = 0.59). Mismatched eyes had worse inflammation compared to matched eyes (P = 0.048). The primary reason for calling TF in the field but not in the photographs appeared to be the number of follicles observed.ConclusionsImage quality did not explain mismatch between field grades and image grades from this prevalence survey. Inflammation made mismatch more likely.Translational RelevanceOur quality grading scheme rapidly identifies image quality issues for training. Standardizing TF grading in the presence of inflammation will improve field and photograph grading.

Optimizing cluster survey designs for estimating trachomatous inflammation–follicular within trachoma control programs

The World Health Organization recommends mass drug administration (MDA) with azithromycin to eliminate trachoma as a public health problem. MDA decisions are based on prevalence estimates from two-stage cluster surveys. There is a need to mathematically evaluate current trachoma survey designs. Our study aimed to characterize the effects of the number of units sampled on the precision and cost of trachomatous inflammation-follicular (TF) estimates. A population of 30 districts was simulated to represent the breadth of possible TF distributions in Amhara, Ethiopia. Samples of varying numbers of clusters (14-34) and households (10-60) were selected. Sampling schemes were evaluated based on precision, proportion of incorrect and low MDA decisions made, and estimated cost. The number of clusters sampled had a greater impact on precision than the number of households. The most efficient scheme depended on the underlying TF prevalence in a district. For lower prevalence areas (< 10%) the most cost-efficient design (providing adequate precision while minimizing cost) was 20 clusters of 20-30 households. For higher prevalence areas (> 10%), the most efficient design was 15-20 clusters of 20-30 households. For longer-running programs, using context-specific survey designs would allow for practical precision while reducing survey costs. Sampling 15 clusters of 20-30 households in suspected moderate-to-high prevalence districts and 20 clusters of 20-30 households in districts suspected to be near the 5% threshold appears to be a balanced approach.

Surveillance for peri-elimination trachoma recrudescence: Exploratory studies in Ghana.

IntroductionTo date, eleven countries have been validated as having eliminated trachoma as a public health problem, including Ghana in 2018. Surveillance for recrudescence is needed both pre- and post-validation but evidence-based guidance on appropriate strategies is lacking. We explored two potential surveillance strategies in Ghana.Methodology/principal findingsAmongst randomly-selected communities enrolled in pre-validation on-going surveillance between 2011 and 2015, eight were identified as having had trachomatous-inflammation follicular (TF) prevalence ≥5% in children aged 1–9 years between 2012 and 2014. These eight were re-visited in 2015 and 2016 and neighbouring communities were also added (“TF trigger” investigations). Resident children aged 1–9 years were then examined for trachoma and had a conjunctival swab to test for Chlamydia trachomatis (Ct) and a dried blood spot (DBS) taken to test for anti-Pgp3 antibodies. These investigations identified at least one community with evidence of probable recent Ct ocular transmission. However, the approach likely lacks sufficient spatio-temporal power to be reliable.A post-validation surveillance strategy was also evaluated, this reviewed the ocular Ct infection and anti-Pgp3 seroprevalence data from the TF trigger investigations and from the pre-validation surveillance surveys in 2015 and 2016. Three communities identified as having ocular Ct infection >0% and anti-Pgp3 seroprevalence ≥15.0% were identified, and along with three linked communities, were followed-up as part of the surveillance strategy. An additional three communities with a seroprevalence ≥25.0% but no Ct infection were also followed up (“antibody and infection trigger” investigations). DBS were taken from all residents aged ≥1 year and ocular swabs from all children aged 1–9 years. There was evidence of transmission in the group of communities visited in one district (Zabzugu-Tatale). There was no or little evidence of continued transmission in other districts, suggesting previous infection identified was transient or potentially not true ocular Ct infection.Conclusions/significanceThere is evidence of heterogeneity in Ct transmission dynamics in northern Ghana, even 10 years after wide-scale MDA has stopped. There is added value in monitoring Ct infection and anti-Ct antibodies, using these indicators to interrogate past or present surveillance strategies. This can result in a deeper understanding of transmission dynamics and inform new post-validation surveillance strategies. Opportunities should be explored for integrating PCR and serological-based markers into surveys conducted in trachoma elimination settings.

Effectiveness of azithromycin mass drug administration on trachoma: a systematic review.

Backgrounds:Azithromycin mass drug administration (MDA) is a key part of the strategy for controlling trachoma. This systematic review aimed to comprehensively summarize the present studies of azithromycin MDA on trachoma; provide an overview of the impact of azithromycin MDA on trachoma in different districts; and explore the possible methods to enhance the effectiveness of azithromycin MDA in hyperendemic districts.Methods:PubMed, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and ClinicalTrials.gov were searched up to February 2021 with no language restriction. Studies reporting the effect of azithromycin MDA on trachoma were included. Mathematical modeling studies, animal studies, case reports, and reviews were excluded. The trachomatous inflammation-follicular (TF) <5.0% was used to judge the effect of azithromycin MDA on eliminating trachoma as a public health problem. Two researchers independently conducted the selection process and risk of bias assessment.Results:A total of 1543 studies were screened, of which 67 studies including 13 cluster-randomized controlled trials and 54 non-randomized studies were included. The effect of azithromycin MDA on trachoma was closely related to the baseline prevalence in districts. For the districts with baseline prevalence between 5.0% and 9.9%, a single round of MDA achieved a TF <5.0%. For the districts with baseline between 10.0% and 29.9%, annual MDA for 3 to 5 years reduced TF <5.0%. However, for the districts with high level of baseline prevalence (TF >30.0%), especially with baseline TF >50.0%, annual MDA was unable to achieve the TF <5.0% even after 5 to 7 years of treatment. Quarterly MDA is more effective in controlling trachoma in these hyperendemic districts.Conclusions:Azithromycin MDA for controlling trachoma depends on the baseline prevalence. The recommendation by the World Health Organization that annual MDA for 3 to 5 years in the districts with TF baseline >10.0% is not appropriate for all eligible districts.

Comparison of genovars and Chlamydia trachomatis infection loads in ocular samples from children in two distinct cohorts in Sudan and Morocco.

Trachoma is a blinding disease caused by repeated conjunctival infection with different Chlamydia trachomatis (Ct) genovars. Ct B genovars have been associated with more severe trachoma symptoms. Here, we investigated associations between Ct genovars and bacterial loads in ocular samples from two distinct geographical locations in Africa, which are currently unclear. We tested ocular swabs from 77 Moroccan children (28 with trachomatous inflammation-follicular (TF) and 49 healthy controls), and 96 Sudanese children (54 with TF and 42 healthy controls) with a Ct-specific real-time polymerase chain reaction (PCR) assay. To estimate bacterial loads, Ct-positive samples were further processed by multiplex real-time qPCR to amplify the chromosomal outer membrane complex B and plasmid open reading frame 2 of Ct. Genotyping was performed by PCR-based amplification of the outer membrane protein A gene (~1120 base pairs) of Ct and Sanger sequencing. Ct-positivities among the Moroccan and Sudanese patient groups were 60·7% and 31·5%, respectively. Significantly more Sudanese patients than Moroccan patients were genovar A-positive. In contrast, B genovars were significantly more prevalent in Moroccan patients than in Sudanese patients. Significantly higher Ct loads were found in samples positive for B genovars (598596) than A genovar (51005). Geographical differences contributed to the distributions of different ocular Ct genovars. B genovars may induce a higher bacterial load than A genovars in trachoma patients. Our findings emphasize the importance of conducting broader studies to elucidate if the noted difference in multiplication abilities are genovar and/or endemicity level dependent.

Twelve-Year Longitudinal Trends in Trachoma Prevalence among Children Aged 1-9 Years in Amhara, Ethiopia, 2007-2019.

ABSTRACTTrachoma control in the Amhara region of Ethiopia, where all districts were once endemic, began in 2001 and attained full scale-up of the Surgery, Antibiotics, Facial cleanliness, and Environmental improvement (SAFE) strategy by 2010. Since scaling up, the program has distributed approximately 14 million doses of antibiotic per year, implemented village- and school-based health education, and promoted latrine construction. This report aims to provide an update on the prevalence of trachoma among children aged 1–9 years as of the most recent impact or surveillance survey in all 160 districts of Amhara. As of 2019, 45 (28%) districts had a trachomatous inflammation-follicular (TF) prevalence below the 5% elimination threshold. There was a statistically significant relationship between TF prevalence observed at the first impact survey (2010–2015) and eventual achievement of TF < 5% (2015–2019). Of the 26 districts with a first impact survey < 10% TF, 20 (76.9%) had < 5% TF at the most recent survey. Of the 75 districts with a first survey between 10% and 29.9% TF, 21 (28.0%) had < 5% TF at the most recent survey. Finally, among 59 districts ≥ 30% TF at the first survey, four (6.8%) had < 5% TF by 2019. As of 2019, 30 (18.8%) districts remained with TF ≥ 30%. Amhara has seen considerable reductions of trachoma since the start of the program. A strong commitment to the SAFE strategy coupled with data-driven enhancements to that strategy is necessary to facilitate timely elimination of trachoma as a public health problem regionally in Amhara and nationwide in Ethiopia.

Population-Based Prevalence of Chlamydia trachomatis Infection and Antibodies in Four Districts with Varying Levels of Trachoma Endemicity in Amhara, Ethiopia.

.The Trachoma Control Program in Amhara region, Ethiopia, scaled up the surgery, antibiotics, facial cleanliness, and environmental improvement (SAFE) strategy in all districts starting in 2007. Despite these efforts, many districts still require additional years of SAFE. In 2017, four districts were selected for the assessment of antibody responses against Chlamydia trachomatis antigens and C. trachomatis infection to better understand transmission. Districts with differing endemicity were chosen, whereby one had a previous trachomatous inflammation-follicular (TF) prevalence of ≥ 30% (Andabet), one had a prevalence between 10% and 29.9% (Dera), one had a prevalence between 5% and 10% (Woreta town), and one had a previous TF prevalence of < 5% (Alefa) and had not received antibiotic intervention for 2 years. Survey teams assessed trachoma clinical signs and took conjunctival swabs and dried blood spots (DBS) to measure infection and antibody responses. Trachomatous inflammation-follicular prevalence among children aged 1–9 years was 37.0% (95% CI: 31.1–43.3) for Andabet, 14.7% (95% CI: 10.0–20.5) for Dera, and < 5% for Woreta town and Alefa. Chlamydia trachomatis infection was only detected in Andabet (11.3%). Within these districts, 2,195 children provided DBS. The prevalence of antibody responses to the antigen Pgp3 was 36.9% (95% CI: 29.0–45.6%) for Andabet, 11.3% (95% CI: 5.9–20.6%) for Dera, and < 5% for Woreta town and Alefa. Seroconversion rate for Pgp3 in Andabet was 0.094 (95% CI: 0.069–0.128) events per year. In Andabet district, where SAFE implementation has occurred for 11 years, the antibody data support the finding of persistently high levels of trachoma transmission.

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

ObjectivesThe objectives of the study were to estimate the prevalence of different clinical signs of trachoma and identify possible factors associated with TF.MethodologyFollowing 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).ResultsThe 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).ConclusionsTrachoma 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.

Ocular Chlamydia trachomatis infection and infectious load among pre-school aged children within trachoma hyperendemic districts receiving the SAFE strategy, Amhara region, Ethiopia.

BackgroundAfter approximately 5 years of SAFE (surgery, antibiotics, facial cleanliness, environmental improvement) interventions for trachoma, hyperendemic (trachomatous inflammation-follicular (TF) ≥30%) districts remained in Amhara, Ethiopia. This study’s aim was to characterize the epidemiology of Chlamydia trachomatis (Ct) infection and load among pre-school aged children living under the SAFE strategy.MethodsConjunctival swabs from a population-based sample of children aged 1–5 years collected between 2011 and 2015 were assayed to provide Ct infection data from 4 endemic zones (comprised of 58 districts). Ct load was determined using a calibration curve. Children were graded for TF and trachomatous inflammation-intense (TI).Results7,441 children were swabbed in 4 zones. TF and TI prevalence were 39.9% (95% confidence Interval [CI]: 37.5%, 42.4%), and 9.2% (95% CI: 8.1%, 10.3%) respectively. Ct infection prevalence was 6.0% (95% CI: 5.0%, 7.2%). Infection was highest among children aged 2 to 4 years (6.6%-7.0%). Approximately 10% of infection occurred among children aged 1 year. Ct load decreased with age (P = 0.002), with the highest loads observed in children aged 1 year (P = 0.01) vs. aged 5 years. Participants with TF (P = 0.20) and TI (P<0.01) had loads greater than individuals without active trachoma.ConclusionsIn this hyperendemic setting, it appears that the youngest children may contribute in meaningful ways towards persistent active trachoma.

Associations between Water, Sanitation and Hygiene (WASH) and trachoma clustering at aggregate spatial scales, Amhara, Ethiopia

BackgroundTrachoma is the leading infectious cause of blindness globally. The WHO has recommended the SAFE (Surgery, Antibiotics, Facial cleanliness and Environmental improvements) strategy to eliminate trachoma as a public health problem. The F and E arms of the strategy will likely be important for sustained disease reductions, yet more evidence is needed detailing relationships between hygiene, sanitation and trachoma in areas with differing endemicity. This study addressed whether the regional differences in water, sanitation, and hygiene (WASH) variables were associated with the spatial distribution of trachomatous inflammation-follicular (TF) among children aged 1 to 9 years in the Amhara National Regional State of Ethiopia.MethodsData from 152 multi-stage cluster random trachoma surveys were used to understand the degree of clustering of trachoma on two spatial scales (district and village) in Amhara using a geographical information system and the Getis-Ord Gi* (d) statistic for local clustering. Trained and certified graders examined children for the clinical signs of trachoma using the WHO simplified system. Socio-demographic, community, and geoclimatic factors thought to promote the clustering of the disease were included as covariates in a logistic regression model.ResultsThe mean district prevalence of TF among children aged 1 to 9 years in Amhara was 25.1% (standard deviation = 16.2%). The spatial distribution of TF was found to exhibit global spatial dependency with neighboring evaluation units at both district and village level. Specific clusters of high TF were identified at both the district and the village scale of analysis using weighted estimates of the prevalence of the disease. Increased prevalence of children without nasal and ocular discharge as well as increased prevalence of households with access to a water source within 30 minutes were statistically significantly negatively associated with clusters of high TF prevalence.ConclusionsWater access and facial cleanliness were important factors in the clustering of trachoma within this hyperendemic region. Intensified promotion of structural and behavioral interventions to increase WASH coverage may be necessary to eliminate trachoma as a public health problem in Amhara and perhaps other hyper-endemic settings.

Pgp3 seroprevalence and associations with active trachoma and ocular Chlamydia trachomatis infection in Malawi: cross-sectional surveys in six evaluation units.

BackgroundFollowing one to five years of antibiotic mass drug administration (MDA) for the elimination of trachoma as a public health problem, programmes must conduct impact surveys to inform decisions on whether MDA is still needed. These decisions are currently based on the prevalence of trachomatous inflammation—follicular (TF), which, after MDA, correlates poorly with prevalence of ocular Chlamydia trachomatis infection.Methodology/Principal findingsImpact surveys in six evaluation units (EUs) of Malawi were used as a platform to explore associations between the prevalence of TF, ocular C. trachomatis infection and anti-Pgp3 antibodies one year after the third annual round of MDA. Participants were examined for trachoma using the World Health Organization simplified grading system. Ocular swabs and dried blood spots (DBS) were collected from children aged 1–9 years. Swabs were tested for C. trachomatis DNA using GeneXpert. DBS were assayed for anti-Pgp3 antibodies using ELISA. EU-level prevalence of TF in children aged 1–9 years ranged from 4.7% (95% CI 3.4–6.3) to 7.2% (95% CI 5.8–8.9). Prevalence of C. trachomatis infection in children ranged from 0.1% (95% CI 0.0–0.6) to 0.7% (95% CI 0.3–1.3) while Pgp3 seroprevalence ranged from 6.9% (95% CI 5.4–8.6) to 12.0% (95% CI 10.1–14.0) and increased with age.Conclusions/SignificanceBased on current global policy, the prevalence of TF indicates that a further year of antibiotic MDA is warranted in four of six EUs yet the very low levels of infection cast doubt on the universal applicability of TF-based cut-offs for antibiotic MDA. Pgp3 seroprevalence was similar to that reported following MDA in other settings that have reached the elimination target however the predictive value of any particular level of seropositivity with respect to risk of subsequent infection recrudescence is, as yet, unknown.

Progress toward Elimination of Trachoma as a Public Health Problem in Seven Localities in the Republic of Sudan: Results from Population-Based Surveys.

.Trachoma is the leading cause of infectious blindness in the world. After baseline surveys demonstrated that Sudan was endemic for trachoma, the Sudan Federal Ministry of Health (FMOH) Trachoma Control Program conducted trachoma prevention and treatment interventions in endemic localities. The Sudan FMOH conducted population-based trachoma prevalence surveys between September 2016 and April 2017 in seven localities across five states of Sudan to document current trachoma prevalence estimates and measure water, sanitation, and hygiene (WASH) indicators. Children aged 1–9 years were examined for five clinical signs of trachoma, and participants of all ages were examined for trachomatous trichiasis (TT). A household questionnaire was administered to gather demographic and WASH-related information. The prevalence of trachomatous inflammation-follicular (TF) in children aged 1–9 years ranged from 0.4% (95% CI: 0.1–1.1%) to 6.4% (95% CI: 3.3–11.9%). Trachomatous trichiasis in those aged 15 years and older ranged from 0.1% (95% CI: 0.0–0.6%) to a high of 4.4% (95% CI: 2.1–9.1%). Of seven localities surveyed, four localities had achieved the elimination threshold of less than 5% TF in children aged 1–9 years. Six localities still required interventions to achieve less than 0.2% TT in those aged 15 years and older. The presence of latrine ranged from a low of 10.8% (95% CI: 5.2–21.1%) to 88.4% (CI: 81.5–93.0%) and clean face among children ranged between 69.5% (95% CI: 63.5–75.0%) and 87.5% (95% CI: 81.2–91.9%). These results demonstrate that Sudan is within reach of eliminating trachoma as a public health problem.

Progress to Eliminate Trachoma as a Public Health Problem in Amhara National Regional State, Ethiopia: Results of 152 Population-Based Surveys.

.At baseline in 2006, Amhara National Regional State, Ethiopia, was the most trachoma-endemic region in the country. Trachoma impact surveys (TIS) were conducted in all districts between 2010 and 2015, following 3–5 years of intervention with the WHO-recommended SAFE (surgery, antibiotics, facial cleanliness, and environmental improvement) strategy. A multistage cluster random sampling design was used to estimate the district-level prevalence of trachoma. In total, 1,887 clusters in 152 districts were surveyed, from which 208,265 individuals from 66,089 households were examined for clinical signs of trachoma. The regional prevalence of trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense among children aged 1–9 years was 25.9% (95% CI: 24.9–26.9) and 5.5% (95% CI: 5.2–6.0), respectively. The prevalence of trachomatous scarring and trachomatous trichiasis among adults aged ≥ 15 years was 12.9% (95% CI: 12.2–13.6) and 3.9% (95% CI: 3.7–4.1), respectively. Among children aged 1–9 years, 76.5% (95% CI: 75.3–77.7) presented with a clean face; 66.2% (95% CI: 64.1–68.2) of households had access to water within 30 minutes round-trip, 48.1% (95% CI: 45.5–50.6) used an improved water source, and 46.2% (95% CI: 44.8–47.5) had evidence of a used latrine. Nine districts had a prevalence of TF below the elimination threshold of 5%. In hyperendemic areas, 3–5 years of implementation of SAFE is insufficient to achieve trachoma elimination as a public health problem; additional years of SAFE and several rounds of TIS will be required before trachoma is eliminated.

Prevalence of trachoma within refugee camps serving South Sudanese refugees in White Nile State, Sudan: Results from population-based surveys.

BackgroundThe world is witnessing mass displacement of populations which could impact global efforts to eliminate neglected tropical diseases such as trachoma. On the African continent, South Sudan has experienced high levels of population displacement. Population based baseline trachoma surveys were conducted among refugee camps in two Sudanese localities hosting South Sudanese refugee populations to determine whether the SAFE strategy was warranted.Methodology/Principal findingsCross-sectional, multi-stage, cluster-random surveys were conducted within refugee camps in each of two Sudanese localities, Al Salam and Al Jabalain. For survey sampling, multiple camps within each locality were combined to form the sampling frame for that locality. Household water, sanitation and hygiene indicators were assessed, and trachoma signs were graded by trained and certified graders. The prevalence of trachomatous inflammation-follicular (TF) in children aged one to nine years was 15.7% (95%CI: 12.1–20.2) in Al Salam and 10.6% (95%CI: 7.9–14.0) in Al Jabalain. The prevalence of trachomatous trichiasis (TT) in those 15 years above was 2.9% (95%CI: 1.8–4.8) in Al Salam and 5.0% (95%CI: 3.8–6.6) in Al Jabalain. The presence of water and sanitation was high in both survey units.Conclusion/ SignificanceSudan has made progress in reducing the prevalence of trachoma within the country; however, the presence of over one million refugees from a neighboring trachoma hyper-endemic country could impact this progress. These surveys were the first step in addressing this important issue. The results demonstrate that at least three years of mass drug administration with azithromycin and tetracycline is needed in addition to the provision of TT surgical services. Additionally, it highlights that non-endemic or formerly endemic localities may have to adopt new strategies to provide services for refugee populations originating from hyper-endemic regions to ensure elimination of trachoma as a public health problem for all populations.

Sensitivity and specificity of computer vision classification of eyelid photographs for programmatic trachoma assessment

Background/aimsTrachoma programs base treatment decisions on the community prevalence of the clinical signs of trachoma, assessed by direct examination of the conjunctiva. Automated assessment could be more standardized and more cost-effective. We tested the hypothesis that an automated algorithm could classify eyelid photographs better than chance.MethodsA total of 1,656 field-collected conjunctival images were obtained from clinical trial participants in Niger and Ethiopia. Images were scored for trachomatous inflammation—follicular (TF) and trachomatous inflammation—intense (TI) according to the simplified World Health Organization grading system by expert raters. We developed an automated procedure for image enhancement followed by application of a convolutional neural net classifier for TF and separately for TI. One hundred images were selected for testing TF and TI, and these images were not used for training.ResultsThe agreement score for TF and TI tasks for the automated algorithm relative to expert graders was κ = 0.44 (95% CI: 0.26 to 0.62, P < 0.001) and κ = 0.69 (95% CI: 0.55 to 0.84, P < 0.001), respectively.DiscussionFor assessing the clinical signs of trachoma, a convolutional neural net performed well above chance when tested against expert consensus. Further improvements in specificity may render this method suitable for field use.

Prevalence of trachoma in the Afar Region of Ethiopia: results of seven population-based surveys from the Global Trachoma Mapping Project

ABSTRACTPurpose: Trachoma is to be eliminated as a public health problem by 2020. To help the process of planning interventions where needed, and to provide a baseline for later comparison, we set out to complete the map of trachoma in Afar, Ethiopia, by estimating trachoma prevalence in evaluation units (EUs) of grouped districts (“woredas”).Methods: We conducted seven community-based surveys from August to October 2013, using standardised Global Trachoma Mapping Project (GTMP) survey methodologies.Results: We enumerated 5065 households and 18,177 individuals in seven EUs covering 19 of Afar’s 29 woredas; the other ten were not accessible. 16,905 individuals (93.0%) were examined, of whom 9410 (55.7%) were female. One EU incorporating four woredas (Telalak, Dalefage, Dewe, Hadele Ele) was shown to require full implementation of the SAFE strategy for three years before impact survey, with a trachomatous inflammation-follicular (TF) prevalence in 1–9-year-olds of 17.1% (95%CI 9.4–25.5), and a trichiasis prevalence in adults aged ≥15 years of 1.2% (95%CI 0.6–2.0). Five EUs, covering 13 woredas (Berahle, Aba’ala, Dupti, Kurri, Elidihare, Ayesayeta, Afamboo, Bure Mudaitu, Gewane, Amibara, Dulecho, Dalolo, and Konebo), had TF prevalences in children of 5–9.9% and need one round of azithromycin mass treatment and implementation of the F and E components of SAFE before re-survey; three of these EUs had trichiasis prevalences in adults ≥0.2%. The final EU (Mile, Ada’ar) had a sub-threshold TF prevalence and a trichiasis prevalence in adults just >0.2%.Conclusion: Trachoma is a public health problem in Afar, and implementation of the SAFE strategy is required.

Baseline trachoma prevalence in Guinea: Results of national trachoma mapping in 31 health districts

BackgroundBased on previous studies, historical records and risk factors, trachoma was suspected to be endemic in 31 health districts (HDs) in Guinea. To facilitate planning for the elimination of trachoma as a public health problem, national trachoma surveys were conducted between 2011 and 2016 to determine the prevalence of trachomatous inflammation—follicular (TF) and trachomatous trichiasis (TT) in all 31 endemic HDs.Methodology/Principal findingsA total of 27 cross-sectional surveys were conducted, each using two-stage cluster sampling (one survey in 2011 covered five HDs). Children aged 1–9 years and adults aged ≥15 years were examined for TF and TT, respectively, using the World Health Organization (WHO) simplified grading system. Indicators of household access to water, sanitation and hygiene (WASH) were also collected. A total of 100,051 people from 13,725 households of 556 clusters were examined, of whom 44,899 were male and 55,152 were female. 44,209 children aged 1–9-years and 48,745 adults aged ≥15 years were examined. The adjusted prevalence of TF varied between 1.0% (95%CI: 0.6–1.5%) to 41.8% (95%CI: 39.4–44.2%), while the adjusted prevalence of TT ranged from 0.0% (95%CI: 0.0–0.2%) to 2.8% (95%CI: 2.3–3.5%) in the 27 surveys. In all, 18 HDs had a TF prevalence ≥5% in children aged 1–9 years and 21 HDs had a TT prevalence ≥0.2% in adults aged ≥15 years. There were an estimated 32,737 (95% CI: 19,986–57,811) individuals with TT living in surveyed HDs at the time of surveys.Conclusions/SignificanceTrachoma is a public health problem in Guinea. 18 HDs required intervention with at least one round of mass drug administration and an estimated 32,737 persons required TT surgery in the country. The results provided clear evidence for Guinea to plan for national trachoma elimination.

Conjunctival transcriptome profiling of Solomon Islanders with active trachoma in the absence of Chlamydia trachomatis infection

BackgroundClinical signs of active (inflammatory) trachoma are found in many children in the Solomon Islands, but the majority of these individuals have no serological evidence of previous infection with Chlamydia trachomatis. In Temotu and Rennell and Bellona provinces, ocular infections with C. trachomatis were seldom detected among children with active trachoma; a similar lack of association was seen between active trachoma and other common bacterial and viral causes of follicular conjunctivitis. Here, we set out to characterise patterns of gene expression at the conjunctivae of children in these provinces with and without clinical signs of trachomatous inflammation-follicular (TF) and C. trachomatis infection.MethodsPurified RNA from children with and without active trachoma was run on Affymetrix GeneChip Human Transcriptome Array 2.0 microarrays. Profiles were compared between individuals with ocular C. trachomatis infection and TF (group DI; n = 6), individuals with TF but no C. trachomatis infection (group D; n = 7), and individuals without TF or C. trachomatis infection (group N; n = 7). Differential gene expression and gene set enrichment for pathway membership were assessed.ResultsConjunctival gene expression profiles were more similar within-group than between-group. Principal components analysis indicated that the first and second principal components combined explained almost 50% of the variance in the dataset. When comparing the DI group to the N group, genes involved in T-cell proliferation, B-cell signalling and CD8+ T cell signalling pathways were differentially regulated. When comparing the DI group to the D group, CD8+ T-cell regulation, interferon-gamma and IL17 production pathways were enriched. Genes involved in RNA transcription and translation pathways were upregulated when comparing the D group to the N group.ConclusionsGene expression profiles in children in the Solomon Islands indicate immune responses consistent with bacterial infection when TF and C. trachomatis infection are concurrent. The transcriptomes of children with TF but without identified infection were not consistent with allergic or viral conjunctivitis.

Prevalence of trachoma in the Kayes region of Mali eight years after stopping mass drug administration.

BackgroundIn 2009, three years after stopping mass treatment with azithromycin, a trachoma impact survey in four health districts in the Kayes region of Mali found a prevalence of trachomatous inflammation—follicular (TF) among children aged 1 to 9 years of >5% and a trachomatous trichiasis (TT) prevalence within the general population (≥1-year-old) of <1%. As a result, the government’s national trachoma program expanded trichiasis surgery and related activities required to achieve trachoma elimination.Methodology/Principal findingsIn 2015, to assess progress towards elimination, a follow-up impact survey was conducted in the Kayes, Kéniéba, Nioro and Yélimané health districts. The survey used district level two-stage cluster random sampling methodology with 20 clusters of 30 households in each evaluation unit. Subjects were eligible for examination if they were ≥1 year. TF and TT cases were identified and confirmed by experienced ophthalmologists. In total 14,159 people were enumerated and 11,620 (82%) were examined. TF prevalence (95% confidence interval (CI)) was 0.5% (0.3–1%) in Kayes, 0.8% (0.4–1.7%) in Kéniéba, 0.2% (0–0.9%) in Nioro and 0.3% (0.1–1%) in Yélimané. TT prevalence (95% CI) was 0.04% (0–0.25%) in Kayes, 0.29% (0.11–0.6%) in Kéniéba, 0.04% (0–0.25%) in Nioro and 0.07% (0–0.27%) in Yélimané.Conclusions/SignificanceEight years after stopping MDA and intensifying trichiasis surgery outreach campaigns, all four districts reached the TF elimination threshold of <5% and three of four districts reached the TT elimination threshold of <0.1%.

Elimination of trachoma as a public health problem in Ghana: Providing evidence through a pre-validation survey.

BackgroundIn order to achieve elimination of trachoma, a country needs to demonstrate that the elimination prevalence thresholds have been achieved and then sustained for at least a two-year period. Ghana achieved the thresholds in 2008, and since 2011 has been implementing its trachoma surveillance strategy, which includes community and school screening for signs of follicular trachoma and trichiasis, in trachoma-endemic districts. In 2015–2016, the country conducted a district level population-based survey to validate elimination of trachoma as a public health problem.MethodsAs per WHO recommendations, a cross-sectional survey, employing a two-stage cluster random sampling methodology, was used across 18 previously trachoma endemic districts (evaluation units (EUs) in the Upper West and Northern Regions of Ghana. In each EU 24 villages were selected based on probability proportional to estimated size. A minimum of 40 households were targeted per village and all eligible residents were examined for clinical signs of trachoma, using the WHO simplified grading system. The number of trichiasis cases unknown to the health system was determined. Household environmental risk factors for trachoma were also assessed.ResultsData from 45,660 individuals were examined from 11,099 households across 18 EUs, with 27,398 (60.0%) children aged 1–9 years and 16,610 (36.4%) individuals 15 years and above All EUs had shown to have maintained the WHO elimination threshold for Trachomatous inflammation-Follicular (TF) (<5.0% prevalence) in children aged 1–9 years old. The EU TF prevalence in children aged 1–9 years old ranged from between 0.09% to 1.20%. Only one EU (Yendi 0.36%; 95% CI: 0.0–1.01) failed to meet the WHO TT elimination threshold (< 0.2% prevalence in adults aged 15 and above). The EU prevalence of trichiasis (TT) unknown to the health system in adults aged ≥15 years, ranged from 0.00% to 0.36%. In this EU, the estimated TT backlog is 417 All TT patients identified in the study, as well as through on-going surveillance efforts will require further management. A total of 75.9% (95% CI 72.1–79.3, EU range 29.1–92.6) of households defecated in the open but many households had access to an improved water source 75.9% (95%CI: 71.5–79.8, EU range 47.4–90.1%), with 45.5% (95% CI 41.5–49.7%, EU range 28.4–61.8%) making a round trip of water collection < 30 minutes.ConclusionThe findings from this survey indicate elimination thresholds have been maintained in Ghana in 17 of the 18 surveyed EUs. Only one EU, Yendi, did not achieve the TT elimination threshold. A scheduled house-by-house TT case search in this EU coupled with surgery to clear the backlog of cases is necessary in order for Ghana to request validation of elimination of trachoma as a public health problem.