Trachoma is the leading infectious cause of blindness worldwide. Caused by repeated infections with the bacteria Chlamydia trachomatis (Ct), it eventually results in the inward turning of the eyelashes, scratching against the cornea and leading to pain, sight loss and blindness.

Despite the disease being eliminated in most high-income areas globally, there are still 125 million people at risk of developing the condition. More than 67 million of those live in Ethiopia, of which the largest region is Oromia.

Trachoma control programs have only been in place in Oromia since 2016, and there has been a lack of risk factor evidence for the condition from this region to date. A new study from ICEH is the first to investigate risk factors for trachoma and the association with socio-economic status in this area.

The study, part of the wider Stronger-SAFE project to test improved strategies for trachoma control, looked at 1211 individuals in a rural district which had previously been identified as having high rates of trachoma. Each household had at least one child aged 1-9, which are known to be an age group at greater risk of the early stages of the disease.

The households were interviewed and nurses conducted a clinical inspection of people’s eyes, along with taking swabs for the presence of Ct.  

The nurses inspected people for signs of trachoma, in line with the WHO ‘simplified grading system’. This delineates the stages of trachoma into: TF, the early stages of the disease; TI, a more intense presentation; TS, the scarring of the eyelids; and TT, the advanced stage of the disease. ‘Active trachoma’ is assessed as having TF or TI in at least one eye.

The results showed a high percentage of children with trachoma and the presence of Ct. 20% of children aged 1-9 had TF, and nearly 2% had TI. 11% of the children with TF tested positive for Ct, compared with 20% of those with TI.

The researchers also recorded the presence of ocular discharge (28% of all participants), nasal discharge (23%) and flies on face (36.8%).

Adjusting for age, active trachoma was associated with younger age, the lowest income households, the presence of flies on the face and ocular discharge. Pre-school children washing more than once a day, and children whose clothes were washed at least once per week had lower odds of having active trachoma.

This was the first study to investigate socio-economic status and trachoma in Oromia. Even after adjusting for improved hygiene available to people with higher incomes, there was an association between lower socio-economic status and trachoma, suggesting that trachoma disproportionately affects the poorest communities.

Collectively these findings provide further evidence for the utility of hygiene interventions and environmental improvements to reduce the spread of Ct and the development of trachoma. As a highly endemic area, this first study in Oromia is useful for creating robust, region-specific data to tackle trachoma in Ethiopia.

Publication

Shafi Abdurahman O, Last A, Macleod D, Habtamu E, Versteeg B, Dumessa G, et al. (2023) Trachoma risk factors in Oromia Region, Ethiopia. PLoS Negl Trop Dis 17(11): e0011679. https://doi.org/10.1371/journal.pntd.0011679