Risk factors for active trachoma in children and trichiasis in adults: a household survey in Amhara Regional State, Ethiopia

Identification of risk factors is essential for planning and implementing effective trachoma control programmes. We aimed to investigate risk factors for active trachoma and trichiasis in Amhara Regional State, Ethiopia. A survey was undertaken and eligible participants (children aged 1-9 years and adults aged 15 years and above) examined for trachoma. Risk factors were assessed through interviews and observations. Using ordinal logistic regression, associations between signs of active trachoma in children and potential risk factors were explored. Associations between trichiasis in adults and potential risk factors were investigated using conventional logistic regression. A total of 5427 children from 2845 households and 9098 adults from 4039 households were included in the analysis. Ocular discharge [odds ratio (OR)=5.9; 95% CI 4.8-7.2], nasal discharge (OR=1.6; 95% CI 1.3-1.9), thatch roof in household (OR=1.3; 95% CI 1.0-1.5), no electricity in household (OR=2.4; 95% CI 1.3-4.3) and increasing altitude (Ptrend<0.001) were independently associated with severity of active trachoma. Trichiasis was associated with increasing age (ORper 5 year increase=1.5; 95% CI 1.4-1.7), female gender (OR=4.5; 95% CI 3.5-5.8), increasing prevalence of active trachoma in children (Ptrend=0.003) and increasing altitude (Ptrend=0.015).     

Active trachoma in children aged three to nine years in rural communities in Ethiopia: prevalence, indicators and risk factors

Trachoma is the most important infectious cause of blindness worldwide. In two rural populations in Ethiopia, a programme of preventative and treatment measures was initiated in May 2002. A baseline survey was conducted to evaluate the effect of this programme on the prevalence of active trachoma. A total of 1960 children aged 3-9 years, from 915 households in 40 communities, were examined for the presence of active trachoma. Demographic and household information was collected using questionnaires and household amenities and environmental conditions were observed. Overall, 72% of children had active trachoma. Twenty percent of children aged nine years had trachomatous scarring. In children, discharge in the eyes and flies on the eyes were significant indicators of trachoma (odds ratio [OR] = 3.0, 95% CI 1.94-4.55 and OR = 3.4, 95% CI 2.37-4.88, respectively). Frequency of washing children, a clean environment and hygienic disposal of excrement were significant preventative factors for active trachoma. Prevalence of active trachoma varies widely between and within districts. Risk factors comprise a mix of individual characteristics and household factors. This study demonstrates the need for broad target interventions and a flexible approach to the prevention of trachoma in high prevalence endemic rural populations.     

Rapid Trachoma Assessment in Kersa District,Southwest Ethiopia

Background

Trachoma is the leading cause of infectious blindness worldwide. Though trachoma can be treated with antibiotics (active trachoma) or surgery (trachomatous trichiasis), it is still endemic in most parts of Ethiopia. Despite the prevalence of this infectious disease in different parts of the country, district level data is lacking. This study was thus conducted to assess the prevalence estimate of trachoma and its risk factors in Kersa District, Southwest Ethiopia.

Methods

A community based cross sectional Rapid Assessment of Trachoma was conducted using a WHO guideline. Six sub-districts were selected from Kersa District based on primary high risk assessment and from each sub-district; 21–27 households were randomly selected. Active trachoma for children aged 1–9 years, trachomatous trichiasis for people above 15 years old and environmental risk factors for trachoma were assessed. Data were analyzed using SPSS version 16.

Results

The overall prevalence estimate of active trachoma was 25.2% (95% CI: 20.7–30.4%). Forty three percent of children had unclean faces, 11.5% of households had water source at more than half hour walking distance, 18.2% did not have functional latrine, and 95.3% of the households had solid waste disposal within a distance of 20 meters. Households with environmental risk factors were at an increased risk to active trachoma, but the association was not statistically significant (p>0.05). The prevalence estimate of trachomatous trichiasis inclusive of “trachoma suspects” was 4.5%.

Conclusion

Trachoma is endemic in Kersa District with active trachoma being a public health problem in the studied sub-districts. Hence, SAFE strategy should be implemented.     

The relationship between prevalence of active trachoma, water availability and its use in a Tanzanian village

This study aimed to establish the relationship between the prevalence of active trachoma in children, water availability and household water use in a village in Tanzania. Nine hundred and fourteen children aged 1-9 years were examined for signs of trachoma. Data were collected on time taken to collect water, amount of water collected and other trachoma risk factors. In a sub-study, 99 randomly selected households were visited twice daily on two consecutive days to document patterns of water use. The prevalence of active trachoma in the children examined was 18.4% (95% CI 15.9-20.9). Active trachoma prevalence increased with increasing water collection time (OR 2.25; 95% CI 1.13-4.46) but was unrelated to the amount of water collected. In the sub-study, active trachoma prevalence was substantially lower in children from households where more water was used for personal hygiene (P for trend < or =0.01), independent of the total amount of water used. The allocation of water to hygiene was predicted by lower water collection time. The key element in the relationship between water availability and trachoma is the allocation of water within households. Collection time may influence both the quantity of water collected and its allocation within the household.     

Trachoma therapy with topical tetracycline and oral erythromycin: a comparative trial

Because topical antibiotic treatment has had a limited effect in previous controlled trials against trachoma, treatment with oral erythromycin was compared with topical tetracycline in 6-8-year-old children in southern Tunisia who had potentially blinding active trachoma. A total of 169 children were divided into two groups that were carefully matched for age, sex, locality, and intensity of disease. Oral erythromycin ethyl succinate in a paediatric dosage form was administered to one group and topical 1% tetracycline ointment to the other group, twice daily, six days a week for three weeks. The two treatments were equivalent in effectiveness and resulted in a substantial decrease in disease intensity and a marked reduction in chlamydial infection detected in conjunctival smears. To maintain blood levels of antibiotics known to be effective in the treatment of chlamydial infections with a dosage schedule possible in a trachoma control programme, one of the long-acting tetracyclines (doxycycline or minocycline) might be considered. Such systemic chemotherapy should be limited to selective treatment of individuals who can be adequately monitored.     

Rapid assessment for prioritisation of trachoma control at community level in one district of the Kaolack Region, Senegal

The objective of this study was to use a modified Lot Quality Assurance Sampling methodology to classify communities according to prevalence of active trachoma and to estimate the prevalence of trachoma and trichiasis in Nioro department, Kaolack Region, Senegal. A survey was conducted using two-stage cluster sampling to select 50 children aged 2-5 years in each of 33 clusters. In total 1,648 children were examined for active trachoma. Information on trachoma risk factors was collected through interviews with the mother or the household head of the child. Adults (>40 years) with trichiasis were identified through case finding. Nineteen clusters had a low prevalence of active trachoma in children aged 2-5 years (<20%), 11 had medium prevalence (20-40%) and three had high prevalence (>40%). The prevalence of active trachoma in children aged 2-5 years was 17.4% (95% CI 12.9-21.8%). Multivariate-adjusted predictors of active trachoma were: age, facial cleanliness, hygiene practices and keeping cattle in the household. The prevalence of trichiasis in adults aged over 40 years was 1.77% (95% CI 1.24-2.51), equating to 985 adults (95% CI 765-1250) with trichiasis in Nioro department. In conclusion, a survey using rapid methodology showed that trachoma is a problem of public significance in Nioro department, Senegal.     

Prevalence and Pattern of Ocular Morbidity among School Children in Southern Ethiopia

BackgroundVisual health is linked to school achievement, quality of life and productivity. But eye screening in school children is not routinely done in most Ethiopian schools. This study was done to determine prevalence and pattern of ocular morbidity among school children in Roman Dega-Kedida, Southern Ethiopia.MethodThis was a cross-sectional study. All children aged 16 years or less, attending the school during the study period were included. Data entry and statistical analyses were performed using SPSS Version 16. A P - value of < 0.05 was considered statistically significant.ResultA total of 778 children participated in this study. The female to male ratio was 1.06:1. The mean age was 11.34(±2.31) years. A total of 201 (25.8%) children had ocular morbidities. The most common was trachoma found in 85(10.9%). Of these, 49(56.5%) had active trachoma, while 37(43.5%) had either trachoma scar or trachomatous trichiasis. Allergic conjunctivitis was found in 49(6.3%), refractive error in 37(4.8%), and xerophthalmia in 17(2.2%) children. Visual impairment in one or both eyes was found in 41(5.3%) children. Thirty-two children (4.1%) had bilateral Visual impairment of which 6(18.8%) had moderate to severe visual impairment. The cause of visual impairment was refractive error in 37(90.2%), corneal opacity in 3(7.3%) and cataract in 1(2.4%) child.ConclusionMost of the ocular diseases observed were either preventable or treatable. Health education to the community and establishing regular school screening program is recommended.     

Cartography of trachoma in Mali: results of a national survey

Prior to a campaign to eliminate blinding trachoma, a survey of the prevalence of the disease was conducted in the seven administrative regions of Mali between March 1996 and June 1997. In each region (with the exception of Bamako District) a random sample of thirty clusters was taken from the general population, in accordance with the principle of probability proportionate to the size of the communities. All children under 10 years of age and all women over 14 years were examined. The simplified coding proposed by WHO was used for data gathering. A total of 15,310 children and 11,530 women were examined. The prevalence of active trachoma, follicular (TF) or intense (TI), was estimated to be 34.9% among children under 10 years of age (95% CI: 32.3-37.6). The prevalence of TI showing the intensity of trachoma was 4.2% (95% CI: 3.5-5.0) among the same children. The prevalence increased up to the age of 3 years, when it reached 49.2%. The prevalence of TF/TI was 35.7% among boys and 34.3% among girls. The prevalence of entropion trichiasis among women over 14 years of age was 2.5% (95% CI: 2.1-2.9), and 1% had central corneal opacity (95% CI: 0.8-1.3). These prevalences increased with age, such that 10% of women over 70 years of age had trichiasis. By region of the country, the prevalence ranged from 23.1% of active trachoma among children in Ségou, to 46.2% in Gao. The prevalence of entropion trichiasis was 0.65% in Gao region and 3.9% in Koulikoro region. This survey allows the trachoma treatment needs of Mali to be quantified. We estimate that 1.09 million children under 10 years are carriers of active trachoma and require local or general antibiotic treatment. If all the under-10-year-olds from all villages where TF/TI exceeded 20% were to be treated, a total of 2.436 million children would be involved. A total of 85,000 adults should have surgery to correct trichiasis and avoid the onset of blindness.     

Efficacy of oral azithromycin versus topical tetracycline in mass treatment of endemic trachoma

OBJECTIVE: To compare the impact of mass treatment with oral azithromycin and topical tetracycline on the prevalence of active trachoma. METHODS: A total of 1803 inhabitants from 106 households of eight Gambian villages were randomized, in pairs, to receive either three doses of azithromycin at weekly intervals, or daily topical tetracycline over 6 weeks. Ocular examinations were conducted before treatment, and 2, 6 and 12 months after treatment. FINDINGS: Prior to treatment, 16% of the study participants had active trachoma. Two months after treatment, the prevalence of trachoma was 4.6% and 5.1% in the azithromycin and the tetracycline groups, respectively (adjusted odds ratio (OR) = 1.09; 95% confidence interval (CI) = 0.53, 2.02). Subsequently, the prevalence rose to 16% in the tetracycline group, while remaining at 7.7% in the azithromycin group (adjusted OR at 12 months = 0.52; 95% CI = 0.34, 0.80). At 12 months post-treatment, there were fewer new prevalent cases in the azithromycin group, and trachoma resolution was significantly better for this group (adjusted OR = 2.02; 95% CI = 1.42, 3.50). CONCLUSION: Oral azithromycin therefore appears to offer a means for controlling blinding trachoma. It is easy to administer and higher coverages may be possible than have been achieved hitherto.     

Trachoma,flies and environmental factors in Burkina Faso

The presence of flies is one of the earliest risk factors for trachoma and it has been suggested that flies could act as vectors for transmission of chlamydiae. A national trachoma survey was conducted in 1997 in Burkina Faso to (i) study the relationship between trachoma occurrence, flies, dirty faces and some environmental factors, and (ii) investigate the role of flies in the presence of trachoma. The country was stratified into eight groups of provinces and a random sample of 30 clusters was selected in each group. All children aged < 10 years were examined for the diagnosis of active trachoma (trachomatous inflammation which was follicular and/or intense) and the dirtiness of the face and the presence of flies on the face were recorded. The children's carers were questioned about the number of baths given and daily face-washing. Household heads were asked about ownership of cattle and small ruminants. The presence of latrines, a stable, and garbage collection inside the yard was noted. Among 16,514 children examined, 27.0% had active trachoma and 3.3% intense inflammatory trachoma. Flies were present on 11.2% of children's faces and 82.4% and 19.7% of these children had active and intense inflammatory trachoma, respectively. Among the 30.2% of children with dirty faces, 70.2% had active and 10.2% intense inflammatory trachoma. In multivariate analysis, at least one daily bath showed a protective effect on both active and intense inflammatory trachoma. Face-washing twice daily was found to be significantly protective for active trachoma in some regions. A strong association was demonstrated between the presence of flies and dirty faces (odds ratio = 334, 95% confidence interval 202-546). The presence of flies on children's faces, dirty faces and trachoma appeared to be strongly associated. Although the presence of flies may be a marker of socio-economic status and is probably linked with other trachoma risk factors, our data indicated that interventions targeting fly control should be an important issue in controlling trachoma.     

四川省甘孜州高原藏族地区0~6岁儿童维生素A水平与影响因素

目的 考察甘孜藏族自治州0~6岁儿童血清维生素A(VitA)水平,为预防VitA相关疾病的发生提供参考依据。方法 2017年4月-2019年4月在甘孜州乡城县和稻城县对2 122名藏族儿童进行体格检查,并采用高效液相色谱法检测血清VitA的含量。结果 2 122名0~6岁儿童血清VitA平均水平为(1.05±0.27)μmol/L,亚临床缺乏率为8.15%,可疑亚临床缺乏率为45.99%。婴儿组VitA 平均水平为(0.94±0.26)μmol/L,低于幼儿组[(1.09±0.28)μmol/L]和学龄前儿童组[(1.05±0.27)μmol/L](F=15.308),海拔4 km以上VitA 平均水平为(0.96±0.19)μmol/L,低于海拔2~3 km[(0.99±0.26)μmol/L]和3~4 km[(1.12±0.27)μmol/L](F＝61.735),夏季VitA 平均水平高于其他季节(F＝52.194),差异均有统计学意义(P<0.001)。此外0~1岁组亚临床缺乏率为23.97%,高于其他年龄段(χ²=43.503,P<0.001)。Logistic回归分析结果显示海拔高度、季节和年龄对亚临床缺乏和可疑亚临床缺乏均有影响,其中随着海拔升高亚临床缺乏和可疑亚临床缺乏发生几率增大。结论 甘孜藏族自治州0~6岁儿童VitA平均水平较低,以可疑亚临床缺乏为主,VitA的缺乏与年龄、海拔、季节相关,不同年龄阶段儿童应根据当地海拔高度、不同季节补充VitA及富含VitA的食物,以预防VitA缺乏及相关疾病的发生。     

Trachoma in Chad: results of an epidemiological survey

A regional survey was carried out in Chad in 2000 and 2001 to estimate the prevalence and severity of trachoma. The main objectives were to describe the epidemiological pattern in terms of prevalence of inflammatory trachoma and blinding complications in two sub-samples of the population: children under 10 years of age and women over 14. Two strata were identified based on geographical criteria: two regions [Ouadda?-Biltine, North-East] and [Lac-Kanem-Chari Baguirmi, North-West]. Random samples of thirty clusters were selected in each stratum with probability proportional to size. The simplified grading system proposed by the World Health Organisation (WHO) was used. A total of 3,952 children and 2,492 women were examined. The participation in the survey was 95% for the children sample, 92% for the women sample and the representativity of the samples was fairly good. In children under 10 years of age, the prevalence of follicular trachoma (TF) was estimated at 31.5% (IC(95%): 28.6-34.5) and that of intense inflammatory trachoma (TI) at 16.7% (IC(95%) : 14.4-19.2). The severity of the disease is high, as shown by the prevalence of trichiasis-entropion of 1.5% (IC(95%): 0.9-2.2), of central corneal opacity of 1% (IC(95%) :0.6-1.6) and of trachoma-related blindness of 0.5% (IC(95%) : 0.2-1) in women over 14. The epidemiological pattern of trachoma deserves particular attention in the field of public health in Northern Chad, where all indicators are consistently high. The national program for prevention of blindness has prepared a 3-year work plan to implement the SAFE strategy as soon as possible in these areas.     

Household willingness to pay for azithromycin treatment for trachoma control in the United Republic of Tanzania

OBJECTIVE: Household willingness to pay for treatment provides important information for programme planning. We tested for relationships between socioeconomic status, risk of trachoma, perceptions of the effects of azithromycin, and the household willingness to pay for future mass treatment with azithromycin. METHODS: We surveyed 394 households in 6 villages located in central United Republic of Tanzania regarding their willingness to pay for future azithromycin treatment. A random sample of households with children under 8 years of age was selected and interviewed following an initial treatment programme in each village. Data were gathered on risk factors for trachoma, socioeconomic status, and the perceived effect of the initial azithromycin treatment. Ordered probit regression analysis was used to test for statistically significant relationships. FINDINGS: 38% of responding households stated that they would not be willing to pay anything for future azithromycin treatment, although they would be willing to participate in the treatment. A proxy for cash availability was positively associated with household willingness to pay for future antibiotic treatment. Cattle ownership (a risk factor) and being a household headed by a female not in a polygamous marriage (lower socioeconomic status) were associated with a lower willingness to pay for future treatment. A perceived benefit from the initial treatment was marginally associated with a willingness to pay a higher amount. CONCLUSIONS: As those at greatest risk of active trachoma indicated the lowest willingness to pay, imposing a cost recovery fee for azithromycin treatment would likely reduce coverage and could prevent control of the disease at the community level.     

High proportion of 6 to 18-year-old children and adolescents in the United Arab Emirates are not meeting dietary recommendations

In the United Arab Emirates (UAE), overweight, obesity, and associated chronic diseases have recently emerged as major public health concerns among all age groups, including children and adolescents. We hypothesized that although energy needs might be met by the majority of Emirati children and adolescents, their diet quality and intakes of certain micronutrients may not meet recommendations. A cross-sectional design was used to assess dietary intakes of 253 children (6-10 years of age) and 276 adolescents (11-18 years of age) in the UAE. Trained dietitians collected a 24-hour food recall in the homes of the participants. Nutrient intakes were compared with the Dietary Reference Intakes, and food group consumption was compared with MyPyramid recommendations. Results showed that 9 to 13-year-old females consumed 206 kcal/d from candy and sweets and nearly 264 cal/d from sugar-sweetened beverages. The proportion of participants with percentage energy from saturated fat greater than the recommendation ranged from 27.6% (males 9-13 years) to 45.9% (males 6-8 years). Mean intakes of vitamins A, D, and E were lower than the Estimated Average Requirements for all the subgroups. Mean calcium intake was lower than recommendations for all age and sex subgroups. The proportions of participants whose intakes were less than the recommended number of servings from the food groups were substantial: more than 90% of each of the 6 subgroups for the milk group and 100% among 9 to 18-year-old males for vegetables. In conclusion, the results of this study indicate the need for interventions targeting 6 to 18-year-old children and adolescents in the UAE to improve their diet quality.     

Reliability of clinical diagnosis in identifying infectious trachoma in a low-prevalence area of Nepal.

The WHO Alliance for Global Elimination of Trachoma by 2020 has increased the need to identify ocular chlamydial infections by clinical examination in areas of both high and low prevalence. The relationship between clinically active trachoma (as defined by clinical examination) and chlamydial infection is known for areas with hyperendemic trachoma, but not for areas with a low prevalence of the clinical disease. In the present study, we examined, photographed, and DNA tested the conjunctivae of children in the Surkhet district of mid-western Nepal, an area known to have a low prevalence of clinically active trachoma. Although 6% of the children aged 10 years and under were found to have clinically active trachoma, none were found to have chlamydia infection by the most sensitive DNA amplification tests available. A very low prevalence of clinically active trachoma is not necessarily evidence of the presence of chlamydial infection. Therefore, the WHO policy of not recommending an intensive trachoma control effort when the prevalence of clinically active trachoma is less than 10% in children is appropriate for this area of Nepal.     

青海省不同海拔高度地区4～18岁人群先天性心脏病流行病学调查

目的 调查青海省6个州和海东地区3个县4～18岁少年儿童先天性心脏病(CHD)流行病学特征.方法 共计对288 066名少年儿童按初筛、复筛、彩色多普勒超声心动图确定三级筛选方法.分析不同海拔、不同民族CHD患病率及病种分布,探讨性别间及各年龄段间CHD变化及与海拔高度的关系.结果 查出CHD 1633例,总患病率为5.66‰.不同海拔(2000m～、3000m～、4000m～)患病率分别为4.89‰、5.71‰、8.74‰.不同海拔之间患病率差异有统计学意义(χ~2=54.696,P＜0.001),趋势分析表明随着海拔高度的上升总患病率明显增加(χ~2=41.826,P＜0.001).女性总患病率(6.95‰)明显高于男性(4.54‰),χ~2=73.79,P＜0.001.海拔2000m～地区男女性患病率差异无统计学意义(χ~2=0.807,P＞0.05).随海拔升高女性CHD的患病率高于男性,3000 m～(χ~2=84.733,P＜0.001)、4000 m～(χ~2=16.313,P＜0.001).海拔2000m～地区各年龄段间CHD患病率差异有统计学意义(χ~2=18.138,P＜0.001),但患病率不随年龄的增加而变化(χ~2=3.424,P＞0.05).海拔3000m～、4000m～地区CHD患病率随年龄增长而增加,差异有统计学意义(χ~2=19.230,P＜0.001;χ~2=26.894,P＜0.001).各民族间患病率的差异有统计学意义(χ~2=24.456,P＜0.001),其中蒙古族7.55‰、藏族6.40‰、汉族5.32‰、土族5.23‰、回族4.89‰、撒拉族2.22‰.CHD构成比以房间隔缺损(ASD)为主(37.42%),其次为动脉导管未闭(PDA)(28.47%)和室间隔缺损(VSD)(26.01%).但海拔不同其构成比又有不同,海拔2000 m～、3000 m～以ASD为首位,分别占37.80%、37.67%,4000 m～PDA占首位(46.36%).结论 青海省4～7岁少年儿童CHD患病率、病种分布、性别间及各年龄段间变化与海拔高度有关.     

Analysis of the household distribution of trachoma in a Gambian village using a Monte Carlo simulation procedure

Studies on the household distribution of trachoma have reached conflicting conclusions. This paper describes a cross-sectional survey of endemic trachoma in a Gambian village. Cases of active trachoma were mapped, and the compound and household distribution of the disease analysed by a Monte Carlo simulation procedure which takes into account differences in the size and age distribution within individual households. Significant clustering of active trachoma cases both by village compound (p less than 0.0001) and bedroom (less than 0.05) were detected supporting the concept that intra-familial transmission of trachoma is important. There was no evidence of spatial clustering of rooms with higher than expected prevalence of trachoma. Clustering of disease in space or time provides important evidence of infectious aetiology and route of transmission. The methods discussed here are generally applicable in the study of other infectious diseases.     

Risk factors for active trachoma in The Gambia

Trachoma has been endemic in The Gambia for decades but national surveys indicate that the prevalence is falling. Risk factor data can help guide trachoma control efforts. This study investigated risk factors for active trachoma and ocular Chlamydia trachomatis infection in children aged below 10 years in two Gambian regions. The overall prevalence of C. trachomatis infection was only 0.3% (3/950) compared with 10.4% (311/2990) for active trachoma, therefore analyses were only performed for active trachoma. After adjustment, increased risk of trachoma was associated with being aged 1-2 years (odds ratio (OR) 2.20, 95% CI 1.07-4.52) and 3-5 years (OR 3.62, 95% CI 1.80-7.25) compared with <1 year, nasal discharge (OR 2.07, 95% CI 1.53-2.81), ocular discharge (OR 2.68, 95% CI 1.76-4.09) and there being at least one other child in the household with active trachoma (OR 11.28, 95% CI 8.31-15.31). Compared with other occupations, children of traders had reduced risk (OR 0.53, 95% CI 0.30-0.94). At the household level, only the presence of another child in the household with active trachoma was associated with increased risk of active trachoma, suggesting that current trachoma control interventions are effective at this level. In contrast, child-level factors were associated with increased risk after adjustment, indicating a need to increase control efforts at the child level.     

The epidemiology of trachoma in central Tanzania.

Trachoma is the leading infectious cause of blindness worldwide and data are needed on the epidemiological characteristics of active and residual disease in hyperendemic areas. This study describes the epidemiological characteristics of trachoma in Central Tanzania. Active, inflammatory disease peaks in pre-school children, with 60% showing signs of trachoma. Evidence of past infection, scarring, trichiasis, and corneal opacity, rose with age. In this population, 8% of those over age 55 had trichiasis/entropion. Females of all ages had more trachoma than males, with a fourfold increased risk of trichiasis observed in females. Women who were taking care of children appeared to have more active disease than non-caretakers. Clear evidence of clustering of trachoma by village, and within village, by neighbourhood was found. Clustering persisted even after accounting for differences in distance to water, local religion, and proportion of children with unclean faces. These findings have important implications for a trachoma control strategy.