Strategies for the Control and Elimination of Blinding Trachoma
Trachoma is the world's leading cause of preventable blindness. This disease, caused by Chlamydia trachomatis, is endemic in many parts of the developing world. In 1990s we evaluated the use of community-wide treatment with oral azithromycin in a project called Azithromycin in Control of Trachoma (ACT). This approach resulted in clinical improvement and dramatic reduction in prevalence of chlamydial infection through a 1-year follow-up. We enrolled the ACT villages, as well as an additional village that had not had any prior treatments, in our ACT II (2005) study and performed clinical surveys to assess trachoma activity testing conjunctival swabs for the presence of C. trachomatis by nucleic acid amplification tests (NAATs). Thus, we hoped to determine the long-term (10 year) effects of azithromycin treatment.
We have completed the census and clinical survey of the initial three villages. Mass treatment with azithromycin would not be justified with such low rates (1.8 - 4%) of ocular chlamydial infection. We have treated only those living in households with one or more cases of chlamydial infection and we will not follow up on these individually treated families.
In order to achieve the goals of our study, we now propose to identify other more remote villages with trachoma infection rates of 20% or more to evaluate the effect of community-wide treatment with single dose of oral azithromycin. If one or more of these villages (dependent upon population) has trachoma rates of 20% or more they will be invited to participate in the azithromycin treatment. In one set of subjects (1 or 2 villages, dependent upon population and infection rate) we will perform treatment, and follow them up at 2-, 12-, and 24-months post-treatment to ascertain infection rates. In a second set of subjects (1 or 2 villages, dependent upon population and infection rate) we will perform treatment, then perform re-treatment at 30-days post initial treatment, and follow them up at 2-, 12-, and 24-months post-treatment to ascertain infection rates. This should help us determine the need for/and the best time for re-treatment to eliminate blinding trachoma, as some recent studies suggest there is a 2-4% failure rate in the initial treatment. In sum, this study should provide a rational approach to use of community-wide azithromycin treatment to eliminate blinding trachoma as a public health problem