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Trachoma – Written by Dr. Michael Dejene Bejiga, MD, MPH, MSc.

What is trachoma?

Trachoma is a disease of the eye and is the leading infectious cause of avoidable blindness. [1,2] It is caused by infection with a certain strain of bacterium called Chlamydia trachomatus and is transmitted by direct or indirect transfer of eye or nasal discharge of infected people, and passed through contact with fingers, contaminated clothes or bedding and certain species of eye-seeking flies. [3,4] Infection is usually acquired when living in close proximity to others with active disease, and the family is the main setting for transmission. Particularly young children who harbor the disease are the principal reservoir of infection. [5]

The following sections will briefly outline the global burden and public health implications of the condition, its causes, the different stages of trachoma, and some insights into its management and treatment.

The global burden of trachoma

Trachoma remains to be highly prevalent among communities affected by poverty and are exposed to common environmental risk factors like inadequate hygiene, crowded households, inadequate access to water, sanitation and health care. [9-12] Many trachoma sufferers are mothers and children. [9, 12-13] Women may be more susceptible to the condition than men due to greater contact with children in their role as the primary caretaker of the household. [14]

Trachoma is an endemic in Africa, the Eastern Mediterranean Region, Australia and parts of Southeast Asia. [15] It is responsible for the visual impairment or blindness of about 1.9 million people. As of May 2021, 136.2 million people are at risk of trachoma globally and 44 countries require interventions for trachoma. In Africa, 115.7 million people living in 26 countries are at risk of trachoma and are known to require interventions. [6] With 66.7 million people at risk of the disease, Ethiopia is the most trachoma-affected country in the world and carries 49% of the global burden of trachoma. [7]

Trachoma causes a considerable economic burden for individuals and communities in terms of lost productivity from blindness and visual impairment which is estimated to be between US$ 2.9 to 8 billion annually. [4,8]

At what age does trachoma develop

Trachoma can present itself with a number of clinical manifestations that are the result of current or past infections. In areas where trachoma is an endemic, active (inflammatory) trachoma is common among preschool-aged children, with prevalence rates as high as 60–90%. Infection becomes less frequent and shorter in duration with increasing age. [9]

Repeated episodes of active trachoma can scar the eyelids, and, in some individuals, leads to trachomatous trichiasis (TT), in which one or more eyelashes from the upper eyelid to turn inwards and touch the eyeball. [8] TT is an extremely painful eye condition. It can be corrected surgically but, if left untreated, may lead to corneal opacification, low vision and blindness. The age at which this occurs depends on several factors including local transmission intensity. In very highly endemic communities, it can occur in childhood, though the onset of visual impairment between the ages of 30 and 40 years is more typical. Blindness from trachoma is irreversible. [9]

Stages of trachoma

The grading system developed by the World Health Organization (WHO) is used to classify the five stages of blinding trachoma. The different stages of trachoma are characterized by the clinical presentations of the disease that are seen in the affected eye as the disease progresses.

The WHO simplified trachoma grading system presented below includes five clinical signs of the disease, each of which can be present or absent in a person with trachoma. [15]

1. Trachomatous Inflammation – Follicular (TF) – The presence of five or more follicles, each at least 0.5 mm in diameter, in the central part of the upper tarsal conjunctiva. Follicles are round lumps or spots that lie beneath more superficial epithelium and are paler than the surrounding tissue. Care should be taken to distinguish follicles from small scars, conjunctival concretions, cysts and giant papillae.
2. Trachomatous Inflammation – Intense (TI): Pronounced inflammatory thickening of the upper tarsal conjunctiva that obscures more than half of the normal deep tarsal vessels.
3. Trachomatous Scarring (TS): The presence of easily visible scarring in the upper tarsal conjunctiva. Scars are white lines, bands, or sheets in the upper tarsal conjunctiva.
4. Trachomatous Trichiasis (TT): At least one eyelash from the upper eyelid touches the eyeball, or evidence of recent epilation of in-turned eyelashes from the upper eyelid.
5. Corneal Opacity (CO): Easily visible corneal opacity that is so dense that at least part of the pupil margin is blurred when viewed through the opacity. This definition is intended to detect corneal opacities that cause significant visual impairment. In individuals with corneal opacity, visual acuity should be measured, if possible.

If you experience any of these signs and symptoms, schedule an appointment with an eye health professional to get your eyes checked. It is also important to note that the development of myopia may even start before symptoms appear, which makes going for regular and timely eye checks that much more essential.

Treatment for trachoma

The early stages of trachoma (TF and TI) can be treated with oral azithromycin and tetracycline eye ointment. Azithromycin eye drops have also been shown to be very effective antibiotics. [16] While TT, which is potentially blinding form of trachoma, can be treated with a relatively simple surgical procedure conducted in the affected eyelid.

Elimination of trachoma as a public health problem

Trachoma can be classified as the community-level eye disease, thus the fight against it should also start at the community level and the SAFE strategy provides a feasible way to eliminate the disease. [17]

WHO-recommended “SAFE strategy” for the prevention and treatment of trachoma based on community intervention is a package of inter­ventions comprising of four key components: [18]

• Surgery to treat the blinding stage (trachomatous trichiasis)
• Antibiotics to clear infection, particularly mass drug administration of the antibiotic azithromycin
• Facial cleanliness and
• Environmental improvement, particularly improving access to water and sanitation.

The reduction in the transmission of trachoma can occur through general socioeconomic improvement or specific implementation of the antibiotics, facial cleanliness and environmental improvement components of the SAFE strategy for trachoma elimination. [19, 20-22]

The S component of the SAFE strategy is a public health intervention, including active case finding if necessary, recommended when the prevalence of TT “unknown to the health system” is ≥0.2% among people aged ≥15 years. The A, F and E components of SAFE are recom­mended for districts in which the prevalence of the active trachoma sign “trachomatous inflammation—follicu­lar” (TF) is ≥5% in children aged 1–9 years. In such districts, all residents should be offered antibiotic treat­ment annually, the planned number of rounds depend­ing on the most recent estimate of TF prevalence. [23-27]

Elimination of trachoma as a public health problem is defined as:

(i) a prevalence of trachomatous trichiasis (TT) “unknown to the health system” of < 1 case per 1000 total population and

(ii) a prevalence of trachomatous inflammation-follicular (TF) in children aged 1–9 years of < 5%, in each formerly endemic district. TT “unknown to the system” excludes TT in individuals with postsurgical recurrence, TT in individuals who have refused surgery, and TT in individuals who are listed for surgery but have not yet received an operation, but for whom a surgical date has been set. There must also be written evidence that the health system is able to identify and manage incident TT cases, using defined strategies, with evidence of appropriate financial resources to implement those strategies. [28-30]

The proportion of individuals showing clinical signs of trachoma (prevalence) amongst specific age groups in a district remains the key indicator for guiding trachoma control program. WHO recommends using the prevalence of TF in children between 1-9 years and TT in adults aged 15 and over for deciding where to implement different components of the SAFE strategy. [25, 28, 31]

Despite all the efforts made so far, not having enough resources, hard-to-reach populations, inequity, environmental threats and humanitarian crisis remain to be the challenge for the global effort to eliminate trachoma as a public health problem. [27]

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The information, include but not limited to, text, graphics, images and other material contained on this website are for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new healthcare regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.

References

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[6]      ICTC. Key trachoma facts and statistics. https://www.trachomacoalition.org/trachomastatistics.  Accessed on February 2, 2022

[7]      WHO Alliance for the Global Elimination of Trachoma by 2020: progress report on elimination of trachoma, 2020. WHO Weekly Epidemiological Record, 6 August 2021. No 31 2021, 96, 353–364 http://www.who.int/wer

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[15]     Anthony W Solomon, Amir B Kello, Mathieu Bangert, Sheila K West, Hugh R Taylor, Rabebe Tekeraoi & Allen Foster. WHO simplified trachoma grading system. Bull World Health Organ 2020;98:698–705 | doi: http://dx.doi.org/10.2471/BLT.19.248708

[16]    Andrew G Lee. Trachoma Treatment and Management. emedicine.medscape.com/ article/ 1202088-treatement.

[17]     Lei Tian, Ning-Li Wang. Trachoma control: the SAFE strategy. Int J Ophthalmol, Vol. 11, No. 12, Dec.18, 2018 www.ijo.cn

[18]     Solomon A, Zondervan M, Kuper H, Buchan J, Mabey D, Foster A. Trachoma Control: A Guide for Program Managers. Geneva, Switzerland: World Health Organization: World Health Organization; 2006.

[19]     Mun˜ oz B, West S. Trachoma: the forgotten cause of blindness. Epidemiologic Reviews, 1997, 19: 205–217

[20]      Dolin PJ, Faal H, Johnson GJ, Minassian D, Sowa S, Day S, et al. Reduction of trachoma in a sub-Saharan village in absence of a disease control programme. Lancet. 1997 May 24;349(9064):1511–12. doi: http:// dx .doi .org/ 10 .1016/ S0140 -6736(97)01355 -X PMID: 9167460

[21]     Hoechsmann A, Metcalfe N, Kanjaloti S, Godia H, Mtambo O, Chipeta T, et al. Reduction of trachoma in the absence of antibiotic treatment: evidence from a population-based survey in Malawi. Ophthalmic Epidemiol. 2001 Jul;8(2-3):145–53. doi: http:// dx .doi .org/ 10 .1076/ opep .8 .2 .145 .4169 PMID: 11471084

[22]     Hammou J, El Ajaroumi H, Hasbi H, Nakhlaoui A, Hmadna A, El Maaroufi A. In Morocco, the elimination of trachoma as a public health problem becomes a reality. Lancet Glob Health. 2017 03;5(3):e250–1. doi: http:// dx .doi .org/ 10 .1016/ S2214 -109X(17)30023 -2 PMID: 28089329

[23]     Thylefors B et al. A simple system for the assessment of trachoma and its complica­tions. Bull World Health Organ. 1987;65(4):477–83.

[24]      Taylor HR et al. Trachoma. Lancet 2014; 384(9960): 2142–52.

[25]      WHO Fact Sheet on Trachoma 2022. https://www.who.int/news-room/fact-sheets/detail/trachoma. Accessed on February 2, 2022

[26]      WHO Alliance for the Global Elimination of Trachoma by 2020: progress report on elimination of trachoma, 2020. Weekly epidemiological record. No 31 2021, 96, 353–364 http://www.who.int/wer

[27]      ICTC 2021. #EndTrachoma in the WHO African Region: The time is now.

[28]      Report of the 2nd global scientific meeting on trachoma, Geneva, 25-27 August, 2003. Geneva: World Health Organization; 2003.

[29]      Report of the 3rd global scientific meeting on trachoma, Johns Hopkins University, Baltimore, MA, 19-20 July 2010. Geneva: World Health Organization; 2010.

[30]      Validation of Elimination of Trachoma as a Public Health Problem, 2016.   Geneva: World Health Organization; 2016.

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