Understanding Trachoma: A Global Public Health Challenge
Key Facts
Trachoma is a debilitating eye disease caused by the bacterium Chlamydia trachomatis. It poses a significant public health challenge in 38 countries, leading to blindness or visual impairment in approximately 1.9 million individuals. The blindness resulting from trachoma is irreversible, making prevention and timely intervention crucial. As of April 2024, around 103 million people reside in areas where trachoma is endemic, placing them at risk of developing blindness from this disease.
The infection spreads through personal contact—via hands, clothing, bedding, or hard surfaces—and by flies that come into contact with the eye or nasal discharge of infected individuals. Repeated infections can cause the eyelashes to turn inward, leading to painful abrasion of the cornea. In 2023, efforts to combat trachoma included surgical treatment for 130,746 individuals suffering from advanced stages of the disease and antibiotic treatment for 32.9 million people, with a global antibiotic coverage of 29%.
Overview
Trachoma is recognized as the leading infectious cause of blindness worldwide. The disease is primarily transmitted through direct or indirect contact with the eye and nose discharges of infected individuals, especially young children who serve as the main reservoir of the infection. Flies, particularly certain species, play a significant role in spreading the disease by transferring these discharges.
Symptoms and Transmission
In endemic regions, active trachoma is prevalent among preschool-aged children, with prevalence rates soaring between 60% to 90%. While younger children are more frequently infected, the duration and frequency of infections tend to decrease with age. Close living conditions facilitate the spread of the infection, with families being the primary setting for transmission. Although an individual’s immune system can clear a single episode of infection, re-acquisition is common in endemic communities.
Over time, repeated infections can lead to severe scarring of the eyelid (trachomatous conjunctival scarring), causing the eyelashes to rub against the eyeball (trachomatous trichiasis). This condition results in chronic pain and light sensitivity, ultimately leading to corneal scarring. If left untreated, these changes can result in irreversible blindness, with onset typically occurring between the ages of 30 and 40 in highly endemic areas.
The impact of visual impairment extends beyond the individual, affecting families who are often already among the poorest in society. Women are disproportionately affected, experiencing blindness up to four times more frequently than men, likely due to their close contact with infected children.
Environmental factors that exacerbate the transmission of C. trachomatis include inadequate hygiene, overcrowded living conditions, limited access to clean water, and insufficient sanitation facilities.
Distribution
Trachoma is hyperendemic in some of the world’s poorest and most rural regions, affecting communities in Africa, Central and South America, Asia, Australia, and the Middle East. It accounts for about 1.4% of all blindness globally, with Africa being the most affected continent.
As of October 21, 2024, the World Health Organization (WHO) has validated 21 countries, including Benin, Cambodia, and Ghana, as having eliminated trachoma as a public health problem. This progress highlights the potential for successful intervention strategies.
Economic Impact
The economic burden of trachoma is substantial, with estimates suggesting that lost productivity due to blindness and visual impairment costs between US$ 2.9 billion and US$ 5.3 billion annually. When considering the broader implications of trichiasis, this figure rises to approximately US$ 8 billion. The economic strain on affected individuals and communities underscores the urgent need for effective intervention and prevention strategies.
Prevention and Control
Efforts to eliminate trachoma in endemic countries are guided by the WHO-recommended SAFE strategy, which encompasses:
- Surgery: To treat the blinding stage of the disease (trachomatous trichiasis).
- Antibiotics: Mass drug administration of azithromycin, donated by the manufacturer, is crucial for clearing infections.
- Facial Cleanliness: Promoting hygiene practices to reduce transmission.
- Environmental Improvement: Enhancing access to clean water and sanitation facilities.
In 2023, significant strides were made, with 130,746 individuals receiving corrective surgery and 32.9 million treated with antibiotics. However, these numbers are still below pre-pandemic levels, emphasizing the need for continued commitment to elimination efforts.
WHO Response
The WHO has been at the forefront of the global response to trachoma since adopting the SAFE strategy in 1993. The organization launched the WHO Alliance for the Global Elimination of Trachoma by 2020, which aims to support member states in implementing the SAFE strategy and strengthening national capacities through epidemiological surveys and resource mobilization.
The World Health Assembly’s resolution WHA51.11, adopted in 1998, set a target for the global elimination of trachoma as a public health problem by 2020. However, with the endorsement of the neglected tropical diseases roadmap for 2021–2030, the new target date for elimination has been set for 2030.
Conclusion
Trachoma remains a significant public health challenge, particularly in impoverished regions where access to healthcare, sanitation, and education is limited. The disease not only leads to irreversible blindness but also exacerbates poverty and hinders economic development. Continued global efforts, community engagement, and resource allocation are essential to combat this preventable cause of blindness and improve the quality of life for millions at risk. Through sustained commitment to the SAFE strategy and collaboration among various stakeholders, the goal of eliminating trachoma as a public health problem is within reach.