Use of complementary indicators in trachoma surveys in Nigeria: results of impact surveys in two local government areas
Summary
Persistent trachomatous inflammation-follicular (TF) has delayed trachoma elimination in Binji and Silame local government areas (LGAs), Sokoto State, Nigeria. To assess ongoing Chlamydia trachomatis (Ct) transmission, surveys measured TF prevalence, Ct infection and seroconversion rates (SCRs). Binji had TF below the elimination threshold (4.1%), with very low Ct infection (0.1%) and SCR (1.1), indicating elimination of active trachoma. Although Silame’s TF prevalence remained slightly above the threshold (5.6%), Ct infection (0.2%) and SCR (1.6) were also low, suggesting minimal transmission and no need for mass drug administration. Both LGAs can transition to surveillance, highlighting the value of complementary indicators for informed programmatic decisions.