WHO Alliance for the Global Elimination of Trachoma by 2020: progress report, 2019

Overview

Trachoma, caused by certain serovars of Chlamydia trachomatis, is the leading infectious cause of blindness. Infection is transmitted within ocular and nasal secretions that are passed from person to person on fingers, fomites (such as clothing) and eye-seeking flies (particularly Musca sorbens). Ophthalmic infection is associated with an inflammatory conjunctivitis known as “active trachoma”. Repeated episodes of active trachoma can scar the eyelids. In some individuals, this leads to trachomatous trichiasis (TT), in which one or more eyelashes from the upper eyelid touch the eye. TT is extremely painful. It can be corrected surgically, but, if left untreated, may lead to corneal opacification, low vision and blindness.

Trachoma can be eliminated as a public health problem through use of a package of interventions known as the “SAFE strategy”, comprising Surgery for TT, Antibiotics to clear ocular C. trachomatis infection and Facial cleanliness and Environmental improvement (particularly in access to water and sanitation) to reduce C. trachomatis transmission. Surgery should be offered to any individual with TT thought likely to benefit from an operation; the S component of the SAFE strategy is a public health-level 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 (usually populations of 100 000–250 000) in which the prevalence of the active trachoma sign “trachomatous inflammation−follicular” (TF) is ≥5% in children aged 1–9 years. All residents of these districts should be offered antibiotic treatment annually, the planned number of rounds depending on the most recent estimate of TF prevalence. The criteria for elimination of trachoma as a public health problem are: (i) a prevalence of TT unknown to the health system of <0.2% among people aged ≥15 years, and (ii) a prevalence of TF of <5% among children aged 1–9 years in each formerly endemic district and (iii) evidence that the health system can continue to identify and manage incident cases of TT.