1. From the Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland; the
2. Kongwa Trachoma Project, Kongwa, Tanzania; the
3. London School of Hygiene and Tropical Medicine, London, United Kingdom; and the4Medical Research Council Laboratories, Fajara, The Gambia, West Africa.
4. London School of Hygiene and Tropical Medicine, London, United Kingdom; and the