Prevalence of active trachoma and associated factors among school age children in Debre Tabor Town, Northwest Ethiopia, 2019: a community based cross-sectional study

Chlamydia trachomatis is an infectious eye disease caused by Chlamydia trachomatis, an obligate intracellular bacterium. On some occasions, it begins as follicular conjunctivitis, with superficial keratitis and corneal vascularization, and advances to conjunctiva scarring and lid distortion. It is the leading cause of blindness worldwide, and it is spread by eye-to-eye contact, transmission on fingers, fomites, coughing and sneezing, and eye-seeking flies[1, 2].

Approximately 1.3 million people are blind from trachoma, and probably 1.8 million have low vision. Trachoma is endemic in more than 50 countries, predominantly in sub-Saharan Africa, including the Middle East and Asia[3, 4]. According to the WHO weekly epidemiologic record, there were 157.7 million individuals living in districts where active trachoma was a public health hazard in 2018, with 88 percent of them in Africa and half of them (69,802,693) in Ethiopia [5].

The nationwide prevalence of active trachoma (either TF or TI) among children aged 1 to 9, was 40.14 percent in 2007. The prevalence varied significantly by location; the highest prevalence was found in Amhara (62.6%) [6], where Debre Tabor is found. The World Health Organization (WHO) and other concerned bodies have targeted trachoma for elimination by 2020 by implementing the so-called SAFE strategy (surgery for in-turned eyelashes, antibiotics to clear infection, and facial cleanliness and environmental improvement to reduce infection transmission). The global trachoma program has brought considerable success with the SAFE strategy, as 9 formerly endemic countries have recently been eliminated to a level of no more public importance[7, 8].

Although they vary among settings, factors like increased family size and the number of children in the household that create crowded living conditions increase the probability of transmission of active trachoma[9]. Childhood hygiene behaviors such as ocular and nasal secretions and unclean faces attract flies and pave the way for transmission[10]. Likewise, water scarcity also promotes the transmission, which in turn compromises hygienic practices, like face washing. Limited access to latrines increases fecal contamination of the environment, which favors Fly breading is also a mechanical vector for trachoma transmission [11‐14].

Despite the SAFE strategy, which included an annual Mass Drug Administration (MDA) with azithromycin, trachoma remained hyper-endemic in Amhara National Region State, including Debre Tabor town [15, 16]. Understanding the infection and its distribution across different study populations would be beneficial for program planning in hyper-endemic areas. As a result, the goal of this study is to fill in the gaps in knowledge on active trachoma burden and its determinants following SAFE and MDA in the elimination roadmap of neglected tropical disease in Ethiopia.

The finding revealed that active trachoma was high, and is a significant public health problem among school-age children in Debre Tabor town compared to. The overall prevalence of active trachoma was 9.9% (95% CI: 6.9–12.7%). The prevalence of TF and TI were 7.4% (95%CI: 5.1–10.1) and 7.1% (95%CI: 4.6–9.6), respectively.

The prevalence of this study was comparable with results reported from isolated treatment-nave island communities of West Africa (14.7%)[23], Gambela (12.3%)[24], Gondar Zuria (12.1%)[25], and Leku town (11%)[26], These slight variations might be due to the fact that school age children who were attending schools could wash their face and get health education about personal hygiene and active trachoma at school [27], and also might be due to mass drug administration implementation in Debre Tabor town [28] which had reduced the level of active trachoma infection. But, the prevalence was higher compared to the studies in Brazil (3.4%)[29], Shanghai, China (5.2%)[30],Yunnan province (0.2%)[31], India (6.8%)[32], Mali (0.53%)[33], Pakistan (1.91%)[34], Harari region (1.3%) [35], Mali (6.2%), Niger(4.6%), and Nigeria (4.2%) [36], and Benishangul Gumuz Region (7,4%)[37]. High prevalence of active trachoma in this study area might be due to the immigration of people into the town fleeing from civil wars across different areas of the country[38]. Hundreds of thousands of people, mostly women and children, were forced from their homes and livelihoods as a result of the fighting in northern Ethiopia[39], which in turn, overburdens the capacity of water, sanitation, and hygiene facilities.

However, the prevalence in this study was lower than in studies in the Southern Nation Nationalities Peoples Region(> 10%) [40], Madda Walabu (22%) [41], Gonji Kolella (23%)[42], Zala district (36.7%)[43], Gazegibela (52.4%) [44], evaluation survey of active trachoma prevalence in Ethiopia (19.1%)[36], and Sokoto State (37%)[45]. This might be the current finding, and the previous studies mentioned above were not similar by the age of the study population. On the other hand, it might also be due to better access to safe water, improved sanitation and health facilities in areas where this study was conducted compared to the previous studies. In addition, Gazegibela district is repeatedly drought-affected and food-insecure, which is attributed to the high prevalence of trachoma[44].

Multivariable logistic regression analysis implies, the odds of having active trachoma among school-age children from households having greater than 4 family sizes was 3.4 times higher than those from households that had less than or equal to 4 family sizes (AOR = 3.4; 95% CI:1.22–9.49). This result was supported by research conducted in the Brazilian amazon [29], Harari Region [35] and Leku town [26]. This may be due to a lack of time to guardians to take care as the number of school-age children, and families are rising within the household. Besides, the infection rate and severity of trachoma are closely related to the overcrowded living conditions of the households [46, 47]. The probability of direct human contact, sharing sleeping places, towels, and clothing might be increased for ocular Chlamydia to spread[48].

The odds of having active trachoma among children who had unclean faces were 23. 93 times higher than those who had clean face (AOR = 23.93; 95% CI: 8.25–69.4). Similar findings were reported in Mali [33], Zala [49], and Ethiopia [50]. This might be due to the fact that an unclean face attracts eye- seeking flies that transmit trachoma mechanically. Children with unclean faces could be more likely to spread nasal and ocular secretions infected with Chlamydia trachomatis among one another, particularly if they are sharing fomites and cross infection through contaminated fingers [18, 46].

Moreover, the odds of having active trachoma among school-age children who washed their faces without soap were 3.27 times higher compared to those who washed their faces by using soap (AOR = 3.27; 95%CI: 1.19–8.94). This finding is well supported by a systematic review and meta-analysis study [51]. Using soap was the key to abolishing flies, which are the main cause and transmission of trachoma due to the continuous interruption of contact between vectors and children [52].

The odds of having active trachoma among children from households where solid waste was disposed of improperly were 3.02 times higher than those households that disposed of solid waste properly (AOR = 3.02; 95%CI: 1.17, 7.8). This finding is in line with the studies done in the Harari Region [35] and Gazegibela [53]. This may be due to improper solid waste management at the household level, which is a persistent problem in the town that might harbor and support fly breeding [52]. Solid waste is a challenge in Debre Tabor town[54]. Solid waste can create unsanitary conditions to the environment which in turn can lead to pollution of the land and nearby water sources and accelerate outbreaks of vector-borne disease—that is, diseases spread by rodents and insects. This implies that basic sanitation is of paramount importance to prevent trachoma.

In addition, the odds of active trachoma among households having an unimproved type of latrine were 5.18 times higher than those from households who have an improved type of latrine (AOR = 5.18; 95%CI: 1.90–13.69). This finding is parallel with that of Darfur [55], because inadequate sanitation favors the breeding site of flies [18, 56]. As a limitation of the study, school wash facility and livestock factors were not included in the study.

The prevalence of active trachoma among school-age children was high compared to WHO’s definition of trachoma as a public health problem [57]. Improper home solid waste management, an unimproved type of toilet, an unclean face, the lack of soap during face washing, and a household with more than four family sizes were significantly associated factors to active trachoma. This finding implies the need for mass drug administration to reduce the burden of active trachoma among school age children. Promotion of behavioral determinants through health education programs like keeping facial cleanliness by washing their child’s face with soap, managing solid waste properly, and installing improved latrines to reduce active trachoma needs to be in place. The promotion of the utilization of family planning to improve short birth intervasl, and thereby reduce the number of children in a household would be important.