Trachoma

Abstract

Trachoma is the leading infectious cause of blindness worldwide and the eighth commonest blinding disease. Blinding trachoma is hyperendemic in many of the poorest and most remote rural areas in 53 countries. Africa alone harbors about 44 % of the global total cases. Caused by the obligate intracellular bacterium C. trachomatis of the four ocular serovars (A, B, Ba, and C), the recurrent episodes of conjunctival infection, and the associated chronic inflammation it causes, initiate a scarring process that ultimately leads to irreversible blindness. The genital serovars (D to K) of C. trachomatis can infect the conjunctiva causing either ophthalmia neonatorum in infants or inclusion conjunctivitis in adults. Infection is probably usually acquired through living in close physical proximity to an infected person, with the family as the principle unit for transmission. Trachoma has two major phases: active or inflammatory trachoma, the key sign of which is the “trachoma follicle,” that is lymphoid follicles or germinal centers in the superior tarsal conjunctiva and cicatricial or late trachoma, marked by structural change in the lid with tarsal scarring and trichiasis. In hyperendemic settings, infection may be acquired in early infancy, whereas in meso-endemic and hypo-endemic regions, it is probably on average later. Active trachoma is predominantly seen in young children, becoming less frequent and of shorter duration with increasing age, while trichiasis and corneal opacity are more common in women than men. Control of trachoma is based on the SAFE strategy, which is composed of Surgery for trichiasis cases, Antibiotics to treat the community pool of infection, Face washing, and Environmental improvement to reduce transmission. The major challenges in national trachoma control programs have been the generation of baseline data, conducting baseline surveys, and scaling up of program interventions due to inadequate funds. The prevailing insecurity and inaccessibility in some of the endemic countries are another critical impediment to effective implementation. More research is required in diagnostics, use of photography for trachoma grading, Mass Drug Administration and especially alternative treatment strategies, determination of threshold level at which infection disappears without MDA, monitoring and evaluation, and defining the endgame strategies. The outlook for the fight against trachoma in next decade is bright given all the various parameters that have been put in place with the hope that nobody would go blind from trachoma after the elimination target date, 2020.