Population-based prevalence surveys were undertaken to determine whether trachoma is a public health problem in Laos requiring implementation of the SAFE strategy (surgery, antibiotics, facial cleanliness, environmental improvement).
The country was divided into 19 evaluation units (EUs), each containing a population of roughly 100,000-350,000 people. Of these, 16 were believed most likely to harbor trachoma (based on historical evidence), and were mapped using the Global Trachoma Mapping Project methods. A 2-stage cluster sampling was used to sample approximately 1222 children aged 1-9 years in each EU, as well as all adults aged 15 years and older resident in households with children. The presence or absence of trachomatous inflammation - follicular (TF) and of trichiasis was documented in each subject, and prevalences (adjusted for age and sex) estimated.
The adjusted prevalence of TF in 1-9-year-olds ranged from 0.2% to 2.2% across the 16 EUs. Adjusted all-ages prevalence of trichiasis was 0.00% in 13 EUs, 0.06% in two EUs, and 0.12% in one EU. The trichiasis prevalence in adults in the last EU was 0.19%.
The assessment included all areas of Laos suspected of ever harboring trachoma and most of the rural population of the country. The low prevalence of TF and trichiasis do not warrant any special programs against trachoma at this time.
The purpose of this study is to analyze the relationships among clinical signs (follicular trachoma) and the prevalence of infection and antibody and to determine whether it may be appropriate to consider one or more alternative indicators for deciding whether trachoma programs can stop MDA.