Effects of intervention with the SAFE strategy on trachoma across Ethiopia.

BACKGROUND/AIMS: The impact of the SAFE strategy (surgery, antibiotics, face washing, environmental hygiene), recommended to eliminate blinding trachoma, is not well explored. We determined the operational effectiveness of the whole SAFE intervention package. METHODS: Analytical cross-sectional trachoma surveys were conducted in four program areas across Ethiopia before and after 3 years of intervention with the SAFE strategy. A total of 8358 children 1-9 years, 4684 people above 14 and 3572 households were assessed in the follow-up evaluations using methodologies recommended by the WHO. Effects were measured by comparing follow-up proportions with baseline estimates of four key indicators. RESULTS: Coverage was 36% for trichiasis surgery, 59% for antibiotic and 57% for health-promotion services. Prevalence of trachoma trichiasis (TT) decreased from 4.6% (95% CI: 3.6% to 5.8%) down to 2.9% (CI: 2.1% to 3.9%). Prevalence of trachoma inflammation-follicular (TF) dropped from 36.7% (33.9% to 39.6%) to 18.4% (CI: 15.4% to 21.8%). The proportion of unclean faces and households not using latrines fell from 72.8% (68.9% to 76.4%) and 74.5% (69.9% to 78.7%) down to 47.0% (CI: 43% to 51%) and 51.7% (47.2% to 56.2%), respectively. All the reductions related with antibiotic (TF), face washing (clean face) and environmental (latrine) components were statistically significant except for Surgery (TT). CONCLUSIONS: Considerable decline in the magnitude of trachoma and its risk factors was observed in areas where the SAFE strategy was implemented. The coverage of services should be maintained or improved in order to eliminate blinding trachoma by the year 2020

Modelling urban run-off : a quasilinear approach

The non-linear behaviour of catchments, as ascertained by various investigators, is discussed. Blackbox analysis with Laguerre functions shows non-linear behaviour for a small urban catchment area. Some approaches to non-linear systems for rainfall and run-off are considered. Two quasilinear methods are compared with a theoretical model for their application. Results from an application of the most promising method on an urban catchment area confirm the feasibility of this method. Six conceptual models are compared and an application of the quasilinear method is given with a conceptual model. A satisfactory treatment of losses forms a major problem in modelling urban rainfall and run-off. Hence a chapter is devoted to transformation of rainfall into sewer inflow and concurrent losses. The use of critical sequences of rainfall for modelling is discussed. Evidence suggesting the maximum time interval between samples is given.<p/