The global burden of trachoma: a review

Abstract

Trachoma is the commonest infectious cause of blindness worldwide. Recurrent infection of the ocular surface by Chlamydia trachomatis, the causative agent, leads to inturning of the eyelashes (trichiasis) and blinding corneal opacification. Trachoma is endemic in more than 50 countries. It is currently estimated that there are about 1.3 million people blind from the disease and a further 8.2 million have trichiasis. Several estimates for the burden of disease from trachoma have been made, giving quite variable results. The variation is partly because different prevalence data have been used and partly because different sequelae have been included. The most recent estimate from the WHO placed it at around 1.3 million Disability-Adjusted Life Years (DALYs). A key issue in producing a reliable estimate of the global burden of trachoma is the limited amount of reliable survey data from endemic regions.

Figure 1. Clinical features of trachoma.

(A) Active trachoma in a child, characterised by a mixed papillary (TI) and follicular response (TF). (B) Tarsal conjunctival scarring (TS). (C) Entropion and trichiasis (TT). (D) Blinding CO with entropion and trichiasis (TT).

Figure 2. Map of trachoma endemic countries in 2009.

Reproduced with permission from Silvio P. Mariotti, WHO/NMH/PBD.