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Overview of trachoma

Heathcote R Wright, PhD FRANZCO
Hugh R Taylor, AC, MD
Section Editor
Peter F Weller, MD, FACP
Deputy Editor
Elinor L Baron, MD, DTMH


Trachoma is a contagious eye infection caused by Chlamydia trachomatis and is the leading infectious cause of blindness worldwide. C. trachomatis is transmitted by intimate social or sexual contact. Serotypes A, B, Ba, and C cause trachoma, and serotypes D to K cause genital tract infection. (See "Clinical manifestations and diagnosis of Chlamydia trachomatis infections" and "Treatment of Chlamydia trachomatis infection".)


Trachoma is endemic in over 50 countries [1]. It is generally confined to resource-limited settings in developing nations of Africa, the Middle East, Asia, Latin America, Pacific Islands, and remote Aboriginal communities in Australia (figure 1) [2,3]. Worldwide, over 80 million people have active trachoma, over 7 million have trichiasis (ingrown eyelashes), and over 1 million have blindness due to corneal scarring [4].

Active infection with C. trachomatis is mostly seen in young children with a peak incidence around four to six years, while subsequent scarring and blindness is seen in adults (figure 2). In many regions, women have two to six times the rate of trachoma than men [5,6], which may be due to women's ongoing exposure to children with C. trachomatis infection [7].

Transmission — Trachoma is spread by direct contact with eye, nose, and throat secretions from affected individuals (figure 3). It can also be spread by contact with fomites such as handkerchiefs, towels, or washcloths contaminated with these secretions. Eye-seeking flies such as Musca sorbens can carry C. trachomatis, but there is no animal or insect reservoir [2,8,9].

Survey assessment — Since most patients with active trachoma are asymptomatic and are young children (figure 2), survey methods are needed to identify populations at risk. The choice of a survey method must take into account the anticipated trachoma prevalence and concerns specific to a local community. Population-based surveys remain the gold standard for determining prevalence and for establishing and monitoring intervention programs. Rapid assessment protocols also have an important role.


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Literature review current through: Sep 2016. | This topic last updated: Mar 12, 2015.
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