What more is there to learn about trachoma?

few minutes spent searching Medline reveals some interesting trends: while the total number of scientific publications has exploded over the past 35 years, the number of papers incorporating the keyword " trachoma " has actually decreased (Fig 1A). The number of reviews of trachoma, however, has increased (Fig 1B). Is this a sign that the study of trachoma has matured— that effective treatments are well known and that the only challenge left is to implement them? Many recent editorials have indeed suggested that a wide variety of treatments are effective. 1–6 In fact, studies suggest that trachoma is disappearing even in the absence of a programme specifically targeting the disease. 7–10 Is the war against trachoma, or at least the scientific part, finally over? The past decade has witnessed numerous advances in chlamydia research: the chlamydial genome has been sequenced, 11 diagnosis with sensitive nucleic acid amplification tests has become routine, 12–14 and randomised clinical trials have purported to demonstrate the efficacy of behavioural, 15 pharmacological, 16 and even entymological 17 control measures in reducing the prevalence of trachoma. A course of three doses of oral azithromy-cin administered to all members of a community was shown to be as effective as a 6 week course of topical tetracycline. 18 This is important because compliance with oral azithromycin is clearly far superior. Another trial suggested that an intensive face washing programme helped reduce the severity, if not the prevalence, of active disease. 15 Chemical fly control in a village not only reduces the number of eye-seeking flies (Musca sorbens), but also may have an effect on the prevalence of active trachoma. 17 Is trachoma this easy to eradicate? As revolutionary as these studies have been, there are reasons why the success observed in research studies may not be achieved in an actual trachoma programme. A research programme that can concentrate on a small number of villages can achieve higher coverage of the population than national programmes that must spread their attention over hundreds of villages. Some research investigators have done such a thorough job of enrolling and treating patients that they have covered over 95% of the intended population. 18 Trachoma programmes however have had coverage of 80% 19 or even less. Mathematical models imply that coverage will be one of the key determinants of whether infection can be progressively reduced with repeated periodic treatments. 20 Many recent studies have been …