Prevalence and risk factors of active trachoma among rural preschool children in Wadla district, Northern Ethiopia

BackgroundTrachoma is the neglected eye problem and the primary cause of preventable corneal blindness. In endemic areas, an initial infection can occur in early childhood, and when there is recurrence, it progresses to scarring and blindness. In the past certain decades, trachoma eliminated from developed countries through enhancements of hygiene and sanitation under immense commitments of the governments but still a problem of developing countries. Studies and reports also indicated that the Amhara region had the highest prevalence of trachoma of the other regions in Ethiopia. Thus, the aim of this study was to asse{Birlie, 2016 #48}ss prevalence and risk factors of active trachoma among rural preschool children in Wadla district, Amhara region, north Wollo zone, northern Ethiopia. Methods: Although the sample size was 583, a total of 596 children were screened for signs of active trachoma because of the sampling procedure nature, cluster sampling technique. Wadla district was had 150 rural villages, which were similar in topography and socio-demographic status. Of these villages, 30 were selected randomly as sites of data collection. An interview on the socio-demographic status with heads of households was held by health informatics professionals. The interview questioners were prepared through reviewing the literature and pretested in Meket Woreda. Eye examination was performed by integrated Eye care workers who were trained for one month for the purpose of trachoma screening. They were also involved in two national trachoma surveys as trachoma sign graders for Carter center-Ethiopia. Results - The prevalence of active trachoma among rural pre-school children in Wadla district was 130 (21.8%). On logistic regression, poor economic status (AOR (95% CI), (3.8 (1.3-11.4), being in 37- 48 months old (AOR (95% CI), (4.2 (1.5-12.0), lived in thatched house roof (AOR (95%CI), (4.4 (1.4-13.6), presence of fly in nearby home (AOR (95% CI), 4.6 (2.1-9.9), once weekly face washing frequency (AOR (95% CI), 8.6

Trachoma is usually a disease of poverty, and poor hygiene [7][8][9], that primarily infect children [5], and then adult women because of their proximity. In addition, preschool children are the main pool of trachoma infection [10]. Although, trachoma infects entire families and communities [11], it is more prevalent on children. In hyperendemic areas, active trachoma was the most common problem of preschool children with a prevalence rate of 60-90%, particularly in areas with poor water supply [10].
Trachoma transmitted through direct eye to eye spread, hand to hand contacts, or indirect spread through sharing of towels, fomites, pillows, eye seeking flies, coughing, and sneezing [12].
Globally, 60 to 80 million people were had been active trachoma and 2.3 million people were had been disability-adjusted life years [13]. More than 200 million people lived in trachoma endemic areas worldwide, 12.4 million children were suffering from active trachoma. Of the landmasses, Africa is the most affected continent with 27.8 million (68.5%) trachoma infected children [14].
Almost 50% of the worldwide burden of active trachoma was highly distributed in three African countries including Ethiopia, Malawi, and Nigeria [15]. Whereas more than 80% of the burden of active trachoma concentrated in 14 countries including Ethiopia, Mozambique, Egypt, Pakistan, Nigeria, and 9 other countries [16]. The global loss of productivity related to impaired vision and blindness from trachoma was thought to be as high as $US 5.3 billion annually [17].
WHO's 2002 global estimation indicated that there were 37 million blind people, and 124 million people with low vision. The burden of blindness in the sub-Saharan Africa region was some of the worst in the world. Fortunately, seventy-five percent of all blindness in developing countries could be prevented or cured [18].
The prevalence of blindness and low vision in Ethiopia was also among the highest in sub-Saharan Africa [18]. This degree of blindness was because of trachoma, as it is the leading cause of blindness worldwide, and especially in many developing countries [19].
Back in history and currently, Ethiopia is one of the most trachoma-affected countries in the world [18,20].
A study in Nigeria [21] revealed the presence of flies on the face of children and absence of latrine as risk factors of active trachoma. A survey in 4 African countries showed that the prevalence of trachomatous follicular was highest among children aged 2-5 years in Ethiopia and Niger [22]. Studies in Ethiopia reported female sex, having an unclean face, not using soap, poor face washing habits, and absence of latrine as risk factors of active trachoma [18,23]. A study in Gonder province revealed that being in 1 to 5 years old had an association with active trachoma [24]. According to the World Health Organization's SAFE (Surgery, Antibiotic, Facial cleanness and Environmental change) strategy recommendation [25]; Ethiopia launched the VISION 2020 initiative in 2002 [26].
In the past certain decades, trachoma was eliminated from developed countries through enhancements of hygiene and sanitation under immense commitments of those governments but still a problem of developing countries. While trachoma was endemic in developed countries, governments were constructed health facility called trachoma hospital or trachoma clinic mainly for the treatment and care center for trachoma clients Furthermore, the prevalence and risk factors of active trachoma vary from setting to setting, and studying the prevalence and risk factors in this rural community would help to recognize the burden of the infection and its association with socio-demographic, economic, environmental and other determinant variables. The study was also conducted after 5 successive years of mass drug administration in the study area and could be considered as an evaluation of program effectiveness after the intervention.

Study design, period and setting
A community based cross-sectional study design was used from March 11/2017 to April 26/2107 in Wadla district. Wadla district is one of the administrative centers in the North Wollo zone, Amhara region. The capital city of the district is Kone. The town far away 725 km from the capital city of Ethiopia, Addis Ababa, and 75 km from Lalibela. The population of Wadla district was 128,170 with 64,574 males and 63, 596 females. There were 28,414 households in this district and resulting in having an average of 4.51 persons per house ratio [35]. The district had 1 general hospital, 7 health centers, and 20 health posts.

Population
The source population was children aged 1-5 years and their mothers in 150 rural villages of Wadla district. Whereas the study populations were children aged 1-5 years old and their mothers in 30 selected clusters or villages of Wadla district. The study units were rural households that had preschool children.

Sample size determination
The sample size estimated using a single population proportion formula. The assumptions used were a proportion of previous study 35.7% [21] from a study done in Nigeria, 95% CI, 5% margin of error, 1.5 design effect, and 10% non-response rate. It was calculated as n= (Z @/2 ) 2 p (1-q )   [14] ( Figure 1).
The heads of the households were interviewed for sociodemographic and economic information, housing and environmental conditions. Children were examined for the signs of trachoma from the 12 selected rural kebeles, and then 30 villages accordingly. Trachomatous trichiasis (TT): the presence of at least one eyelash rubs on the eyeball, or evidence of eyelash removal within two weeks before data collection periods [2,6,7].

Exclusion and Inclusion Criteria
All rural preschool children who lives in the district for at least 6 months and available during the data collection period were included. Seriously ill children or mothers who was not cooperative because of their illness for the data that the researchers required were excluded.

Data collection tools and procedures
Face to face interviews, observation using a checklist, and clinical eye examination were used to collect the data. The interview part on sociodemographic status, environmental, and housing conditions were collected by experienced diploma health informatics professionals using structured interview questioners, which were prepared through reviewing pieces of literature [33,36]. All the socio-demographic status, housing, and environmental condition, observation checklist, and eye examination tools were pretested, and validated before data collection in Kosomender, Meket district. This is one of the boundaries to the south of Wadla district. A household wealth index was computed using the composite indicator for rural residents using assets: livestock ownership, size of agricultural land and quantity of crop production. trachomatous trichiasis (TT), and corneal opacity (CO) [4].

Data analysis and presentation
The data were checked for completeness, coded and entered into Epidemiological Information (Epi -info) version 7 and then transferred to statistical package for social science version 23 for analysis. The data were also checked for normality using Hosmer-Lemeshow-goodness-of-fit. Both bivariable and multivariable analysis was carried out and variables in bivariable analysis with p-value of 0.25 included for multivariable analysis.
Potential co-linearity was also considered and tested. Variables with a P-value of less than 0.05 in multivariable analysis were considered as statistically significant. A principal component analysis was performed to categorize the households' wealth index into lowest or poor, middle, and highest or rich. The result of the analysis expressed in descriptive and inferential statistics. The finding was also presented in the forms of tables, and figures. The main output of the study was presented in considering both types of trachoma ( Figure 2).

Data Quality Assurance
The questionnaire was prepared in English and translated to Amharic, and then translated

Socio-demographic status of households
In this study, a total of 596 preschool children from 499 households were screened for signs of active trachoma and making a response rate of 100%. Nearly three fourth,  (Table 1).

Environmental characteristics of households
Households that used less than 20 liters of water per day were accounted for 180 (36.1%) and 459 (92%) of the households got water after walking 1/2hr. This 1/2hr walking was the minimum time among all households but the maximum hour to fetch water was 4hr. The minimum distance of households from local town was 0.4 km and the maximum distance was 9 km with a median distance of 2km. In addition, the minimum distance of households from the nearest health center was 0.5km and the maximum distance was 13 km with the median distance of 3km. Nearly, 147 (29.5%) of the houses were had clean grass house roof, 133 (26.7%) of houses had thatched corrugated iron roof, 139 (27.9%) of house had thatched grass roof, and 80 (16%) of houses were had clean corrugated iron roof ( Table   2).  Table 3).   (Table 4).

Discussion
The objective of this study was to assess the current status of active trachoma and to identify risk factors among children aged 1 -5 years in the rural communities of Wadla district. The prevalence of Active Trachoma in rural Wadla district among rural preschool children was 21.8%, [(95%, CI), (18%, 25%)]. This prevalence puts the district on 3 years of mass drug administration as the World Health Organization's recommendation [25]. The recommendation is stated as if the prevalence of TF≥10% to <30%, mass drug administration for the population at the district level for at least 3 years is required [25]. Because the maximum years of mass drug administration to decrease the prevalence of active trachoma to below 10% in an endemic area is 5 years [25]. The result was agreed with some studies [18,23,32,36] that reported the prevalence of Active Trachoma was above 20%. This current evidence together with this literature assures that trachoma is still a public health problem. In more comparison, the finding also agreed with previous reports and researches [23,37]  The similarity is expected as both of the studies were conducted on pre-school children from one region, the Amhara region. The finding of this study was lower than that of the studies done in southern Sudan 64.5% [38], in Egypt 49% [39], and in Nigeria 35.7% [21].
This variation might be the result of different study periods and differences in health care service. Because this study conducted after 8 years relative to those studies used to referee. In addition, intensive SAFE strategy implementation in all endemic countries have reached a peak in the past seven years, which contributed to this low result report.
Similarly, the finding is lower than many studies 59.2% [40] [24]. The difference might be because of different study populations, the difference in the level of urbanization and difference in infrastructure.
This study was done only in rural children aged 1 to 5 years but the comparative one is in urban children aged 1 -9 years old [24]. The other possible reason may be that trachoma is highly prevalent in pre-school children than children aged 1-9 years old.
The prevalence of TI in this study area was 3.4% agreed with the study conducted in South Wollo zone 4.3% [41], and lower than the study in the South Gonder zone 7.0% [41]. This discrepancy might be the result of different study subjects and this discrepancy agreed with the statement that the progress of trachoma from one stage to another stage is gradual and increases as age increases [2].

Conclusions
The prevalence of active trachoma among rural preschool children was found to be high as per the WHO recommended thresholds to initiate trachoma control strategies (>10% prevalence), which indicates that active trachoma is still a major public health problem in the study area. But this study is studied on pre-school children only, who had the highest prevalence of trachoma than studies studied on children aged 1-9 years. Some environmental factors were also found to be associated with active trachoma than other variables and this may use as evidence for policymakers to emphasize on the environmental components of the SAFE strategy mainly on facial cleanness and environmental hygiene.

Limitation
The study has some important limitations that should be considered when inferring the results. The first limitation, the study did not take stool sample and unable to show the association of active trachoma with sanitation and hygiene as supported with intestinal parasitic infections. Second, the lack of researches done on children aged 1 to 5 years cause to discuss the finding with researches done on children aged 1 to 9 years. This might decrease the reliability of the discussion section as preschool children had high prevalence of active trachoma than children aged 1 to 9 years old. Third, most of the studied variables were more subjective by nature and may be susceptible to reporting bias regardless of rigorous methodology and quality assurance procedure as the data was collected based on self-reported information.

Ethical Consideration
An ethical approval letter was obtained from Mekelle University, College of health science.

The study protocol was evaluated and approved by the Health Research Ethics Review
Committee [HRERC 0917/2017] of the College of Health Sciences, Mekelle University.
Written permission was also obtained from Woldia zonal health department and send to Wadla district health office. The Woreda health office have also approved the permission written by North Wollo zone health department. Finally, a written consent was taken from children's mothers for interview and eye screening after explaining the purpose of the study. Confidentiality was also maintained by omitting the name and personal identification of respondents (both children and caregivers) because it was not compelled to the study.

Consent for Publication
Participants were informed and gave their written consent to publish the findings in reputable international journal.    Face washing frequency of children (self-report) 2 or more times per a day 108 Once daily 79 2 to 6 times per week 149 Once weekly 167 Stays unwashed for longer than a week. 93 Habit of child bathing for at least one times per a week (self-report)

Yes 445
No 151 Use of soap for face washing (self-report)

Yes 264
No 332 Use of soap for hand washing (self-report) Took drug during mass drug administration in the last year (self-report)

Yes 515
No 81 Note: "*" = P -value less than 0.001 and "**" = P -value less than 0.05 Figure 1 The schematic diagram of sampling procedure in assessing prevalence and risk factors of active trachoma among rural pre-school children in Wadla district, 2017

Figures
The sample size calculated was 583 using single population proportion formula, but as the sampling procedure was cluster sampling, the screening was included 596 pre-school children.