In 1957, Chlamydia trachomatis (non-genital serovars A, B, Ba and C) was recognized as the aetiological agent of trachoma.1 C trachomatis genital serovars D to K cause ophthalmia neonatorum and conjunctivitis in older children and adults. Trachoma remains endemic in many countries of sub-Saharan Africa, the Middle East and other areas of the developing world.2 Nucleic acid amplification testing (NAAT) represented a major advance in the diagnosis of C trachomatis infection among patients with trachoma, cell culture being rarely available in endemic countries. Even using this most sensitive technology, however, one fifth of patients with severe trachoma and up to one half of those with milder infections do not have …