Comparison of two approaches to measuring clean faces as part of the facial cleanliness component of the SAFE trachoma elimination strategy.

BACKGROUND: The Alliance for the Global Elimination of Trachoma (GET) endorses the full SAFE strategy to eliminate trachoma; Surgery (for trichiasis), Antibiotics (to reduce the community pool of infection, Facial cleanliness, and Environmental improvement (to decrease transmission). There is no accepted measure of facial cleanliness. This study compared two possible metrics for facial cleanliness. METHOD/FINDINGS: Metric one: Clean face was defined as observed absence of ocular and nasal discharge on the face. Metric two: observing a grade of dirtiness (scale 10 = lightest to 0 = darkest) on a standard facial wipe. The reliability of grading a child's face or grading a facial wipe was determined in children in Kongwa Tanzania. We also observed both measurements in a cohort of 202 children ages 1 to <7years prior to face cleaning, immediately afterwards, and 4 hours afterwards. Fifty of the children did not have face cleaning and were controls. Intra-and interobserver reliability was similar for both measures, the latter = 0.53 for observing a clean face and 0.52 for grading a facial wipe. There was no correlation between the two. Both measures detected facial cleaning, compared to control children who were not cleaned, immediately after cleaning; control children with 53% clean faces and wipe score of 6.7 compared to cleaned children with 88% clean faces and wipe score of 8 (p = .0001, p = < .0001, respectively). Both measures also detected face washing 4 hours previously compared to controls. CONCLUSIONS: The two metrics were equally reliable, and both measured the behavior of face washing. They measure different aspects of a clean face; one measures the amount of dirt on wiped area and the other measures ocular and nasal discharge. Both measurements appear to capture the behavior of facial cleaning, and the choice of metric would appear to rest on the measurement that captures the stated objective of the behavior, consideration of costs, training, logistics, and implementation.

Gender differences in trachomatous scarring prevalence in a formerly trachoma hyperendemic district in Tanzania.

BACKGROUND: Trachoma is a chronic conjunctivitis caused by the bacterium Chlamydia trachomatis. Repeated infections lead to trachomatous conjunctival scarring which can progress to potentially blinding trachomatous trichiasis (TT). In trachoma hyperendemic conditions, women compared to men have an increased risk of scarring and TT, which can progress to blinding corneal opacification. This study determined if there were gender differences in scarring prevalence and severity when trachoma prevalence approaches elimination, in a formerly trachoma hyperendemic region. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional prevalence study was conducted amongst adults age 15 years and older in Kongwa district, Tanzania in 2019. 3168 persons over age 15 years agreed to be examined and had at least one eye with a gradable image. Ocular photographs were graded for scarring according to a published four-step severity scale. Overall, about half of all study participants had scarring. However, more females (52.3%) had any scarring compared to males (47.2%), OR = 1.22 (95% CI = 1.05-1.43). For every year increase in age, there was a 6.5% increase in the odds of having more severe scarring (95% CI: 5.8%, 7.2%). Women were more likely than men to have severe scarring, OR 2.36 (95% CI: 1.84-3.02). Residence in a community with TF≥10% was associated with a 1.6-fold increased odds of any scarring. CONCLUSIONS/SIGNIFICANCE: Overall scarring prevalence and more severe scarring prevalence was higher in females compared to males, even adjusting for age and community TF prevalence. The data suggest that processes occur that lead to women preferentially progressing towards more severe scarring compared to men.

Comparing image quality and trachoma detection across three camera types from a survey in Kongwa, Tanzania.

BACKGROUND: There is an increasing demand for photography for trachoma prevalence surveys. In previous studies, digital single lens reflex (DSLR) images were superior to smartphone images, but newer-model smartphones and/or lens attachments may be able to bridge this gap. This study compares the image quality and ability to detect trachomatous inflammation - follicular (TF) of three camera types: a DSLR Nikon camera, an iPhone SE and an iPhone 13 Pro with a cell scope. METHODS: We surveyed 62 children ages 1-7 y from two Tanzanian communities. Upper tarsal conjunctiva images of both eyes were graded for TF by two standardized graders. The McNemar's test and a logistic regression model were used for analyses. RESULTS: The DSLR camera malfunctioned during the study, thus the iPhone SE and iPhone 13 Pro with cell scope were both more likely to take high-quality, gradable photographs (88% and 86%, respectively) compared with the DSLR camera (69%) (p<0.001 and p=0.02, respectively). TF was detected in gradable images from the iPhone SE (8.8%) and iPhone 13 Pro with cell scope (9.0%) at the same rate (p=1.0) as images from the DSLR camera (9.7%). CONCLUSION: Smartphones with high-quality image capture, like the iPhone SE/13 Pro, have the potential for use in trachoma surveys if the proportion of gradable images can be improved.

Expanding a photographic grading system for trachomatous scarring.

BACKGROUND: The purpose was to assess an expansion of a previously published photographic four-step severity grading scale for trachomatous scarring (TS). METHODS: Images of everted eyelids of adult women in Tanzania were graded for the presence and severity of TS. The previous S3 grade was subdivided into two categories: S3A, one-third to <50% of the upper eyelid conjunctiva scarred; and S3B, 50% to <90%. The reliability and ease of use were evaluated. This new categorisation was then applied to images taken of the same women 5 y prior to evaluate whether it could help detect previously undetected progression. RESULTS: In total, 142 eyes at baseline and 418 eyes at follow-up after 5 y were graded as S3. Interobserver agreement using the expanded scarring grading scale was a kappa of 0.86. At baseline, 51 (35.9%) eyes were S3A and 91 (64.1%) were S3B. At follow-up after 5 y, 36.6% of the eyes that were previously documented as not having progressed were now detected as having progressed from S3A to S3B. S3B images were more likely to progress to S4 compared with S3A (OR 4.6, 95% CI 2.1 to 9.9). CONCLUSIONS: Adding S3A and S3B is reliable and detects more scarring progression. It will be beneficial for future studies analysing TS in photographs.

The Association Between the Severity of Trachomatous Scarring and Trachomatous Trichiasis Severity in Surgical Patients in Tanzania.

PURPOSE: To determine the association between the severity of trachomatous conjunctival scarring (TS) of the upper eyelid conjunctiva and trachomatous trichiasis (TT) severity in TT surgical patients. METHODS: A cross-sectional study was conducted amongst adults with TT who were referred to surgical camps in Bahi District, Tanzania, for TT surgery. Participants underwent ocular examination. The presence and severity of TS was evaluated in photographs of the everted upper eyelid. TT severity was assessed at the time of the ocular exam based on the number of lashes touching the globe and/or evidence and extent of epilation. Ordinal logistic models were used to examine the association between the severity of TS and TT severity. RESULTS: A total of 627 eyes of 388 participants were included. Mean age was 65 years (ranging from 21-98), 81% were females, and 62% had bilateral TT. 93% of eyes with any TT had at least moderate TS; 62% of eyes had severe TS. An increase in TS severity was associated with an increase in the severity of TT. Using as a reference eyes with none to mild TS, in eyes with moderate TS the odds of increased severity of TT was 1.30 (95% CI 0.67-2.51), in eyes with severe TS the odds was 4.20 (95% CI 2.23-7.92). CONCLUSION: In cases of trachomatous trichiasis presenting for surgery, the severity of TT was significantly associated with the severity of TS with almost all cases of TT having moderate or severe scarring.

A Virtual Reading Center Model Using Crowdsourcing to Grade Photographs for Trachoma: Validation Study.

BACKGROUND: As trachoma is eliminated, skilled field graders become less adept at correctly identifying active disease (trachomatous inflammation-follicular [TF]). Deciding if trachoma has been eliminated from a district or if treatment strategies need to be continued or reinstated is of critical public health importance. Telemedicine solutions require both connectivity, which can be poor in the resource-limited regions of the world in which trachoma occurs, and accurate grading of the images. OBJECTIVE: Our purpose was to develop and validate a cloud-based "virtual reading center" (VRC) model using crowdsourcing for image interpretation. METHODS: The Amazon Mechanical Turk (AMT) platform was used to recruit lay graders to interpret 2299 gradable images from a prior field trial of a smartphone-based camera system. Each image received 7 grades for US $0.05 per grade in this VRC. The resultant data set was divided into training and test sets to internally validate the VRC. In the training set, crowdsourcing scores were summed, and the optimal raw score cutoff was chosen to optimize kappa agreement and the resulting prevalence of TF. The best method was then applied to the test set, and the sensitivity, specificity, kappa, and TF prevalence were calculated. RESULTS: In this trial, over 16,000 grades were rendered in just over 60 minutes for US $1098 including AMT fees. After choosing an AMT raw score cut point to optimize kappa near the World Health Organization (WHO)-endorsed level of 0.7 (with a simulated 40% prevalence TF), crowdsourcing was 95% sensitive and 87% specific for TF in the training set with a kappa of 0.797. All 196 crowdsourced-positive images received a skilled overread to mimic a tiered reading center and specificity improved to 99%, while sensitivity remained above 78%. Kappa for the entire sample improved from 0.162 to 0.685 with overreads, and the skilled grader burden was reduced by over 80%. This tiered VRC model was then applied to the test set and produced a sensitivity of 99% and a specificity of 76% with a kappa of 0.775 in the entire set. The prevalence estimated by the VRC was 2.70% (95% CI 1.84%-3.80%) compared to the ground truth prevalence of 2.87% (95% CI 1.98%-4.01%). CONCLUSIONS: A VRC model using crowdsourcing as a first pass with skilled grading of positive images was able to identify TF rapidly and accurately in a low prevalence setting. The findings from this study support further validation of a VRC and crowdsourcing for image grading and estimation of trachoma prevalence from field-acquired images, although further prospective field testing is required to determine if diagnostic characteristics are acceptable in real-world surveys with a low prevalence of the disease.

Risk factors for the progression of trachomatous scarring in a cohort of women in a trachoma low endemic district in Tanzania.

BACKGROUND: Trachoma, a chronic conjunctivitis caused by Chlamydia trachomatis, is the leading infectious cause of blindness worldwide. Trachoma has been targeted for elimination as a public health problem which includes reducing trachomatous inflammation-follicular prevalence in children and reducing trachomatous trichiasis prevalence in adults. The rate of development of trachomatous trichiasis, the potentially blinding late-stage trachoma sequelae, depends on the rate of trachomatous scarring development and progression. Few studies to date have evaluated the progression of trachomatous scarring in communities that have recently transitioned to a low trachomatous inflammation-follicular prevalence. METHODOLOGY/PRINCIPAL FINDINGS: Women aged 15 and older were randomly selected from households in 48 communities within Kongwa district, Tanzania and followed over 3.5 years for this longitudinal study. Trachomatous inflammation-follicular prevalence was 5% at baseline and at follow-up in children aged 1-9 in Kongwa, Tanzania. 1018 women aged 15 and older had trachomatous scarring at baseline and were at risk for trachomatous scarring progression; 691 (68%) completed follow-up assessments. Photographs of the upper tarsal conjunctiva were obtained at baseline and follow-up and graded for trachomatous scarring using a previously published four-step severity scale. The overall cumulative 3.5-year progression rate of scarring was 35.3% (95% CI 31.6-39.1). The odds of TS progression increased with an increase in age in women younger than 50, (OR 1.03, 95% CI 1.01-1.05, p = 0.005) as well as an increase in the household poverty index (OR 1.29, 95% CI 1.13-1.48, p = 0.0002). CONCLUSIONS/SIGNIFICANCE: The 3.5-year progression of scarring among women in Kongwa, a formerly hyperendemic now turned hypoendemic district in central Tanzania, was high despite a low active trachoma prevalence. This suggests that the drivers of scarring progression are likely not related to on-going trachoma transmission in this district.

Evaluation of photography using head-mounted display technology (ICAPS) for district Trachoma surveys.

BACKGROUND: As the prevalence of trachoma declines worldwide, it is becoming increasingly expensive and challenging to standardize graders in the field for surveys to document elimination. Photography of the tarsal conjunctiva and remote interpretation may help alleviate these challenges. The purpose of this study was to develop, and field test an Image Capture and Processing System (ICAPS) to acquire hands-free images of the tarsal conjunctiva for upload to a virtual reading center for remote grading. METHODOLOGY/PRINCIPAL FINDINGS: This observational study was conducted during a district-level prevalence survey for trachomatous inflammation-follicular (TF) in Chamwino, Tanzania. The ICAPS was developed using a Samsung Galaxy S8 smartphone, a Samsung Gear VR headset, a foot pedal trigger and customized software allowing for hands-free photography. After a one-day training course, three trachoma graders used the ICAPS to collect images from 1305 children ages 1-9 years, which were expert-graded remotely for comparison with field grades. In our experience, the ICAPS was successful at scanning and assigning barcodes to images, focusing on the everted eyelid with adequate examiner hand visualization, and capturing images with sufficient detail to grade TF. The percentage of children with TF by photos and by field grade was 5%. Agreement between grading of the images compared to the field grades at the child level was kappa = 0.53 (95%CI = 0.40-0.66). There were ungradable images for at least one eye in 199 children (9.1%), with more occurring in children ages 1-3 (18.5%) than older children ages 4-9 (4.2%) (χ2 = 145.3, p<0.001). CONCLUSIONS/SIGNIFICANCE: The prototype ICAPS device was robust, able to image 1305 children in a district level survey and transmit images from rural Tanzania to an online grading platform. More work is needed to improve the percentage of ungradable images and to better understand the causes of disagreement between field and photo grading.

Environmental factors and hygiene behaviors associated with facial cleanliness and trachoma in Kongwa, Tanzania.

BACKGROUND: Having a clean face is protective against trachoma. In the past, long distances to water were associated with unclean faces and increased trachoma. Other environmental factors have not been extensively explored. We need improved clarity on the environmental factors associated with facial cleanliness and trachoma prevalence, especially when the disease burden is low. METHODOLOGY/PRINCIPLE FINDINGS: A cross-sectional survey focusing on household environments was conducted in all 92 villages in Kongwa, Tanzania, in a random selection of 1798 households. Children aged 0-5 years in these households were examined for facial cleanliness. In each of the 50 randomly-selected villages, 50 children aged 1-9 years were randomly selected and examined for trachoma. In a multivariate model adjusting for child age, we found that children were more likely to have clean faces if the house had a clean yard (OR 1.62, 95% CI 1.37-1.91), an improved latrine (OR 1.11, 95% CI 1.01-1.22), and greater water storage capacity (OR 1.02, 95% CI 1.00-1.04), and if there were clothes washed and drying around the house (OR 1.30, 95% CI 1.09-1.54). However, measures of crowding, wealth, time spent on obtaining water, or the availability of piped water was not associated with clean faces. Using a cleanliness index (clean yard, improved latrine, washing clothes, ≥1 child in the household having a clean face), the community prevalence of trachoma decreased with an increase in the average value of the index (OR 2.28, 95% CI 1.17-4.80). CONCLUSIONS/SIGNIFICANCE: Access to water is no longer a significant limiting factor in children's facial cleanliness in Kongwa. Instead, water storage capacity and the way that water is utilized are more important in facial cleanliness. A household cleanliness index with a holistic measure of household environment is associated with reduced community prevalence of trachoma.

Patient perceived barriers to surgical follow-up: Study of 6-month post-operative trichiasis surgery follow-up in Tanzania.

BACKGROUND: Post-surgical follow-up is a challenge in low- and middle-income countries. Understanding barriers to trachomatous trichiasis (TT) surgical follow-up can inform program improvements. In this study, patient perceived barriers and enabling factors to follow-up after TT surgery are identified. METHODS: A longitudinal study was carried out in a community-based cohort of persons who received TT surgery in Bahi district, Tanzania. Questionnaires were administered before TT surgery and again after the scheduled 6-month follow-up. Those who did not return were examined at their homes. RESULTS: At baseline, 852 participants were enrolled. Of these, 633 (74%) returned at 6 months and 128 (15%) did not and were interviewed at home. Prior to surgery, attenders were more likely to report familiarity with a community health worker (CHW) (22% vs. 14%; p = 0.01) and less likely to state that time constraints are a potential reason for failure to follow-up (66% vs. 74%; p = .04). At follow-up, non-attenders were more likely to endorse barriers pertaining to knowledge about the need for follow-up, lack of transportation, and satisfaction with surgery. There was no difference in post-operative TT between attenders and non-attenders (23% vs. 18% respectively; p = 0.25). CONCLUSIONS: The outcome of surgery was not a barrier to follow-up. However, better integration of CHWs into their communities and work at coordinating post-surgical care may improve follow-up rates. Moreover, provision of transportation and implementation of effective reminder systems may address patient-perceived barriers to improve follow-up.

Children as messengers of health knowledge? Impact of health promotion and water infrastructure in schools on facial cleanliness and trachoma in the community.

BACKGROUND: Health promotion is essential to the SAFE strategy for trachoma elimination. Schools are a valuable venue for health promotion. However, there is little literature about the impact of health education and water infrastructure in schools on facial cleanliness and trachoma in the community. Our study aimed to describe the current state of school health promotion in Kongwa, Tanzania, and to examine the transferability of health messages from schools to the community at large. METHODOLOGY/FINDINGS: A cross-sectional survey was carried out in all 92 villages in Kongwa district, which included 85 primary schools. Data were collected on health messages and water infrastructure in the schools. A random sample of 3084 children aged 0-5 were examined for facial cleanliness in all villages. In 50 villages, a random sample of 50 children aged 1-9 per village were examined for follicular trachoma (TF). Thirty-seven (44.6%) schools had educational materials on face-washing. Fifty (60.2%) schools had a washing station. The presence of a health teacher was correlated with having posters on face washing in classrooms. The presence of face-washing materials was correlated with the availability of washing stations. Neither teachers mentioning face-washing in health curricula nor educational materials in classrooms were associated with clean faces or trachoma in the community. Having a washing station in the school was associated with lower community rates of trachoma. CONCLUSIONS: Primary school health messages and materials on trachoma were not associated with clean faces or lower rates of trachoma in the community. The target audience for primary school health promotion is likely the students themselves, without immediate rippling effects in the community. A long-term perspective should be considered during the implementation of health promotion in schools. The goal of school health promotion should be training the next generation of parents and community health leaders in combatting trachoma.

Incidence and progression of trachomatous scarring in a cohort of children in a formerly hyper-endemic district of Tanzania.

BACKGROUND: Trachoma is the leading infectious cause of blindness. Repeated or persistent ocular infection with Chlamydia trachomatis in childhood leads to conjunctival scarring, usually in adulthood but often earlier in areas with greater disease burden. There are limited longitudinal data examining change in scarring in children, especially where trachoma rates are low. METHODOLOGY/PRINCIPAL FINDINGS: A cohort of children, ages 1-9 years, were randomly selected at baseline from 38 communities in Kongwa, Tanzania and followed for 2 years. Rates of trachomatous inflammation-follicular (TF) were <5% over the survey period. At baseline, 1,496 children were recruited and 1,266 (85%) were followed-up. Photographs were obtained at baseline and follow-up and graded for the presence and severity of scarring using a four-point scale ranging between S1-S4. In children without scarring at baseline, 1.6% (20/1,246) were found to have incident scarring, and incident scarring was more common among girls compared to boys. Among children with scarring at baseline, 21% (4/19) demonstrated progression. CONCLUSIONS/SIGNIFICANCE: In this formerly hyper-endemic district, the incidence of new scarring in children ages 1-9 years is low, although 21% of those who had scarring at baseline progressed in severity over the 2-year follow-up period. These data provide support for the thesis that while incident scarring more closely reflects ongoing exposure, progression may involve factors independent of ongoing transmission of trachoma.

Ocular Chlamydia trachomatis infection: elimination with mass drug administration.

INTRODUCTION: Ocular Chlamydia trachomatis infection, the causative agent for trachoma, is responsible for 1.9 million cases of visual loss worldwide. Mass Drug Administration (MDA) with azithromycin to entire trachoma-endemic districts is part of the World Health Organization's public health strategy for trachoma elimination. Areas covered: Background on C. trachomatis and the epidemiology of trachoma are presented, followed by a review of the antibiotics for treatment and the need for a public health approach to trachoma elimination. The effectiveness of mass drug administration is presented, concluding with challenges to trachoma elimination in the future. Expert opinion: MDA using azithromycin is a key component of the public health strategy for trachoma elimination. With high coverage in children, there is good evidence that MDA drops the community pool of infection. There are challenges to trachoma elimination by the year 2020, and the drug donation program for country MDAs will be integral to ongoing efforts.

Quantitative Analysis of Endothelial Cell Loss in Preloaded Descemet Membrane Endothelial Keratoplasty Grafts.

PURPOSE: Availability of preloaded Descemet membrane endothelial keratoplasty (pDMEK) tissue may increase acceptance of DMEK in surgical management of endothelial disease. The goal of this study was to determine the safety of pDMEK grafts for 24 hours before surgery by analyzing endothelial cell loss (ECL) using 2 image analysis software programs. METHODS: A total of 18 cadaveric corneas were prepared for DMEK using a standardized technique and loaded in a modified Jones tube injector. Nine of the corneas were injected into Calcein AM vital dye after 1 minute (controls), and the remaining 9 corneas were left preloaded for 24 hours before injection into vital dye for staining. The stained corneas were imaged using an inverted confocal microscope. ECL was then analyzed and quantified by 2 different graders using 2 image analysis software programs. RESULTS: The control DMEK tissue resulted in 22.0% ± 4.0% ECL compared with pDMEK tissue, which resulted in 19.2% ± 7.2% ECL (P = 0.31). Interobserver agreement was 0.93 for MetaMorph and 0.92 for Fiji. The average time required to process images with MetaMorph was 2 ± 1 minutes and with Fiji was 20 ± 10 minutes. Intraobserver agreement was 0.97 for MetaMorph and 0.93 for Fiji. CONCLUSIONS: Preloading DMEK tissue is safe and may provide an alternative technique for tissue distribution and surgery for DMEK. The use of MetaMorph software for quantifying ECL is a novel and accurate imaging method with increased efficiency and reproducibility compared with the previously validated Fiji.

Trachomatous Scarring and Infection With Non-Chlamydia Trachomatis Bacteria in Women in Kongwa, Tanzania.

Purpose: To assess for an association between conjunctival infection with nonchlamydial bacterial species and the presence of trachomatous scarring (TS) in women in central Tanzania. Methods: Cross-sectional data were collected from a random sample of women ages 18 and older in 47 trachoma-endemic communities in Kongwa, Tanzania. Each participant completed a survey, provided a conjunctival swab sample, and received an ocular exam to assess for TS. Biologic samples were cultured for bacterial growth and speciation. Contingency tables were used to assess the associations between TS and bacterial carriage. Results: Complete data was provided by 3882 women (80.7% of invitees). Of all samples, 14% resulted in a positive bacterial isolate. There was no association between TS and nonchlamydial bacterial carriage, whether assessed by species, pathogenicity, or in aggregate. There was a significant association between increasing age and TS severity, but not between age and bacterial carriage. No Corynebacterium was found in the swabs. Conclusions: This study found no association between TS and nonchlamydial ocular infections, although associations with Corynebacterium cannot be ruled out.

Impact of Trichiasis surgery on physical functioning in Ethiopian patients: STAR trial.

PURPOSE: To evaluate the physical functioning of Ethiopian trichiasis surgery patients before and 6 months after surgery. DESIGN: Nested cohort study. METHODS: This study was nested within the Surgery for Trichiasis, Antibiotics to Prevent Recurrence (STAR) clinical trial conducted in Ethiopia. Demographic information, ocular examinations, and physical functioning assessments were collected before and 6 months after surgery. A single score for patients' physical functioning was constructed using Rasch analysis. A multivariate linear regression model was used to determine if change in physical functioning was associated with change in visual acuity. RESULTS: Of the 438 participants, 411 (93.8%) had both baseline and follow-up questionnaires. Physical functioning scores at baseline ranged from -6.32 (great difficulty) to +6.01 (no difficulty). The percentage of participants reporting no difficulty in physical functioning increased by 32.6%; the proportion of participants in the mild/no visual impairment category increased by 8.6%. A multivariate linear regression model showed that for every line of vision gained, physical functioning improves significantly (0.09 units; 95% CI: 0.02-0.16). CONCLUSIONS: Surgery to correct trichiasis appears to improve patients' physical functioning as measured at 6 months. More effort in promoting trichiasis surgery is essential, not only to prevent corneal blindness, but also to enable improved functioning in daily life.

Constant ocular infection with Chlamydia trachomatis predicts risk of scarring in children in Tanzania.

OBJECTIVE: Clinically, constant severe trachoma predicts an increased risk of scarring in children. There are no data on the risk of scarring associated with constant infection with Chlamydia trachomatis, regardless of clinical manifestation. We propose to determine the 5-year incidence of scarring in children with a history of constant severe trachoma, constant infection, or both compared with children who had a history of neither. DESIGN: A 5-year, longitudinal observational study. PARTICIPANTS: Children aged less than 10 years with data on trachoma and infection for 3 of the 5 visits in the first 18 months, and follow-up 5-year data on scarring. METHODS: Data were collected on clinical trachoma, and ocular swabs were taken to determine the presence of C. trachomatis in children in a hyperendemic village in Tanzania. Images were graded for scarring. Data were collected at baseline; 2, 6, 12, and 18 months; and 5 years from baseline. Severe trachoma was defined as the presence of 10 or more follicles, or trachoma intense. A child had constant infection (severe trachoma) if infection (severe trachoma) was present on at least 3 visits before the 5-year survey. MAIN OUTCOME MEASURES: Five-year risk of scarring. RESULTS: Of the 189 children, 22 (11.6%) had constant severe trachoma, but not constant infection. Nine children (4.8%) had constant infection but not constant severe trachoma. Both constant severe trachoma and constant infection were present in 16 children (8.5%). The 5-year incidence of scarring was similar in all 3 groups; children with constant severe trachoma only, with constant infection only, and with both were most likely to develop scars (35.0%, 44.4%, 31.2%, respectively) compared with those with sporadic trachoma or infection (15.2%) or neither (6.8%) (P = 0.0002). CONCLUSIONS: Children with constant infection are also likely to have constant severe trachoma, and their 5-year risk of scarring is high compared with children with sporadic severe trachoma or infection. These data further support the presence of a subgroup of children who cannot clear infection with C. trachomatis, who may manifest a severe immunologic response to infection, and who are at increased risk of scarring sequelae. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Age, sex, and cohort effects in a longitudinal study of trachomatous scarring.

PURPOSE: To determine the 5-year incidence rate of scarring, and associated factors, in the population of Maindi, Tanzania. METHODS: A census of every resident was obtained at baseline, and ocular examinations for the presence and severity of trachoma were performed. Images of the upper eyelid were taken and graded for the presence and severity of scarring, according to a four-step severity scale based on photographs. Five years after baseline, a second series of images was taken and graded for scarring. Incident scarring was defined as new scars in those without scarring at baseline; progression was defined as those with scars that worsened by one step or more at 5 years. RESULTS: The rate of scarring at baseline increased with age, from 1% in the <6-year to 38% in the 41+-year age group. Females at any age had more scarring than did males. The 5-year incidence rate of scarring was 0.20 (95% confidence interval [CI], 0.16-0.25), but varied with age up to 0.43 in the 41+-year group. There was a striking cohort effect, with those aged less than 16 years at baseline having more prevalent scarring and incidence rates comparable to those aged 16 to 40. Progression rates averaged 0.47 (95% CI, 0.36-0.58). CONCLUSIONS: In this trachoma-endemic community, incident scarring was high, especially in the younger cohorts. A dramatic increase in risk of trachomatous scarring occurred approximately 15 years ago and appears to be unabated. Trachoma control programs to reduce risk of scarring are urgently needed to avoid blinding complications in this community.