important facts
Trachoma is an eye disease caused by infection with the bacterium Chlamydia trachomatis. Trachoma is a public health problem in 38 countries and causes blindness or visual impairment in approximately 1.9 million people. Blindness caused by trachoma cannot be reversed. According to data based on April 2024, 103 million people live in trachoma-endemic areas and are at risk of trachoma blindness. Infection is spread by personal contact (through hands, clothing, bedding, or hard surfaces) or by flies that come into contact with secretions from a person’s eyes or nose. Infected person. Repeated infections over many years can cause the eyelashes to pull inward and rub against the surface of the eye. This can be painful and cause permanent damage to the cornea. In 2023, 130,746 people will receive advanced stage surgical treatment and 32.9 million people will receive antibiotic treatment. In 2023, the global antibiotic penetration rate was 29%.
overview
Trachoma is the leading infectious cause of blindness worldwide. It is caused by an obligate intracellular bacterium called Chlamydia trachomatis. The infection is transmitted by direct or indirect contact with eye and nasal secretions of infected people, especially young children, who carry the primary reservoir. These secretions can be spread by certain types of flies.
Symptoms and infection
In areas where trachoma is endemic, active (inflammatory) trachoma is more common in preschool children, with prevalence rates ranging from 60% to 90%. As you get older, infections become less frequent and last for a shorter period of time. Infection usually occurs when people live close to people with active disease, and household members are the main points of transmission. Although an individual’s immune system can clear a single episode of infection, microbial reinfection frequently occurs in endemic communities.
Repeated infections over many years can cause severe scarring on the inside of the eyelids (trachomatous conjunctival scarring), causing them to curve inward and cause the eyelashes to rub against the eyeballs (trachomatous trichiasis), resulting in Continued pain and photo intolerance develop. This and other changes in the eye can cause corneal scarring. If this condition is left untreated, irreversible clouding forms, resulting in visual impairment or blindness. The age at which this occurs depends on several factors, including local infection intensity. In highly endemic areas, onset can occur during childhood, but visual impairment is more common between the ages of 30 and 40.
Visual impairment and blindness lead to a worsening of the life experiences of affected individuals and their families, who are usually already among the poorest of the poor. Women go blind up to four times more often than men. This is probably due to close contact with infected children and consequent more frequent infectious episodes.
Environmental factors associated with stronger transmission of C. trachomatis include:
Inadequate sanitation conditions Crowded households Inadequate access to water Inadequate access to and use of sanitation facilities.
distribution
Trachoma is endemic in many of the poorest rural areas of Africa, Central and South America, Asia, Australia, and the Middle East.
It is responsible for blindness and visual impairment for approximately 1.9 million people. Approximately 1.4% of all blindness worldwide is caused by this disease.
Overall, Africa remains the most affected continent and the continent with the most intensive control efforts.
As of October 21, 2024, 21 countries – Benin, Cambodia, China, Gambia, Islamic Republic of Iran, Lao People’s Democratic Republic, Ghana, India, Iraq, Malawi, Mali, Mexico, Morocco, Myanmar, Nepal, Oman, Pakistan, Saudi Arabia, Togo, Vanuatu and Vietnam had been verified by the WHO to have eradicated trachoma as a public health problem.
economic impact
The burden on individuals and communities affected by trachoma is significant. The economic cost of lost productivity due to blindness and visual impairment is estimated to be between US$2.9 billion and US$5.3 billion annually, increasing to US$8 billion when trichiasis is included.
prevention and control
Eradication programs in endemic countries are being implemented using the SAFE strategy recommended by the WHO. This consists of:
Surgery to treat blindness (trachomatous trichiasis), antibiotics to eliminate infections, especially large doses of the antibiotic azithromycin (which the manufacturer donates to eradication programs through the International Trachoma Initiative), facial Cleanliness. Improving the environment, especially access to water and sanitation.
Most endemic countries have agreed to accelerate implementation of this strategy to achieve elimination goals.
Data reported by member states to WHO in 2023 shows that in the same year, 130,746 people with trachomatous trichiasis underwent corrective surgery and 32.9 million people in endemic areas received antibiotic treatment to eliminate trachoma. It has been shown that In 2019, when COVID-19 did not impact the ability of programs to conduct community-based activities, 92,622 people with trachomatous trichiasis received corrective surgery and 95.2 million people received antibiotics. Received substance treatment.
Eradication efforts must continue to ensure that the goal of eliminating trachoma as a public health problem, set by World Health Assembly resolution WHA 51.11, is achieved (1). Particularly important is the full involvement of multiple actors involved in water, sanitation, and socio-economic development.
WHO response
WHO adopted the SAFE strategy in 1993. WHO’s mission is to provide leadership and coordination to international efforts to eliminate trachoma as a public health problem, and to report on progress towards that goal.
In 1996, WHO launched the WHO Alliance to Eliminate Trachoma Globally by 2020. The alliance supports member states’ implementation of the SAFE strategy and the implementation of epidemiological research, surveillance, surveillance, project evaluation, and resource mobilization.
The World Health Assembly adopted resolution WHA51.11 in 1998, setting a goal of 2020 as the target date for the global eradication of trachoma as a public health problem. The Roadmap for Neglected Tropical Diseases 2021-2030, approved by the 2020 World Health Assembly through Decision 73(33), sets a new target date for global eradication in 2030.
Precautions
(1) Elimination of trachoma as a public health problem is defined as: (i) The prevalence of trachomatous trichiasis “unknown to the health care system” in adults 15 years of age and older; (ii) the prevalence of follicular trachomatous inflammation in children aged 1 to 9 years is less than 5% in each previously endemic region; , lasting for at least 2 years in the absence of continued mass treatment with antibiotics. In addition, (iii) the existence of a system capable of identifying and managing incident cases of trachomatous trichiasis using defined strategies, with evidence of adequate financial resources to implement those strategies.
