Strategies for the control and elimination of blinding trachoma. (360G-Wellcome-078460_B_05_Z)

Trachoma, caused by ocular Chlamydia trachomatis infection, is the commonest infectious cause of blindness. We have shown that a single round of mass treatment with azithromycin can eliminate the infection from endemic populations for up to two years. The studies proposed here will enable this drug to be used to maximum effect. We will Determine the sensitivity and specificity of a new rapid point-of-care (POC) diagnostic test for ocular C. trachomatis infection in communities with high, medium and low prevalence of trachoma in three countries, before and after mass treatment. Use the above data, datasets from our current Wellcome Trust-Burroughs Wellcome Fund grand, to develop optimal sampling strategies to assess the need for community-based mass treatment depending on the prevalence of clinical signs of trachoma or of ocular C. trachomatis infection, determined by the POC test. Use this data to model the impact and cost-effectiveness of strategies in which a POC test is used to decide whether a community should be treated, and to compare this with the cost-effectiveness of the current strategy, based on the prevalence of clinical signs of trachoma.