Presentation on theme: "Module 3 Evaluation unit"— Presentation transcript:
1 Module 3 Evaluation unit Training in monitoring and epidemiological assessment of mass drug administration for eliminating lymphatic filariasisModule 3 Evaluation unit
2 Learning objectives By the end of this module, you should understand: How to define a survey area, known as an evaluation unit (EU).
3 Overview Survey area for a TAS Defining an EU Combining IUs Dividing IUGeographical area of an EU
4 Sample size and critical cut-off Survey area for a TASIf all the data from relevant IUs confirm that they are eligible for a TAS, planning can begin.The first step in designing a TAS is to define the survey area.1. Survey areaEvaluation unit2. Survey siteSchoolCommunity3. Sampling strategyCluster-based samplingSystematic samplingCensus4. Sample sizeSample size and critical cut-off
5 Survey area for a TASImplementation unit (IU): The administrative unit in a country used for MDAEvaluation unit (EU): An area selected for a TAS
6 Defining an EUIUs within an EU can be combined, divided or remain the same, but all IUs in a country in which MDA is conducted must be included in a TAS.IUs in an EU are usually contiguous.All IUs in an EU should have had at least five effective rounds of MDA (i.e. ≥ 65% total population) and meet all the eligibility criteria for conducting a TAS.All areas in the EU should have similar epidemiological features and LF transmission dynamics (e.g. epidemiological drug coverage, baseline prevalence, prevalence of Mf or Ag in sentinel and spot- check sites, principal parasites, vector abundance).The population should not exceed 2 million.
7 Combining IUs 2 1 Endemic IU 3 MDA #1 #2 #3 #4 #5 Unit Total populationBaseline Mf prevalence (%)MDA coverage (%)Sentinel site Mf prevalence (%)(after fifth round)Spot-check site Mf prevalence (%)#1#2#3#4#5132 9832.18169797623.4786777720.30.1352 1382.975706821Endemic IU3MDA
8 Dividing an IU Endemic IU MDA 1 2 3 #1 #2 #3 #4 #5 1 798 234 1.8 2 Total populationBaseline Mf prevalence (%)MDA coverage (%)Sentinel site Mf prevalence (%)(after fifth round)Spot-check site Mf prevalence (%)#1#2#3#4#52.879667174720.20.3Endemic IUMDA12Sub-districtTotal populationBaseline Mf prevalence (%)11.825.431.23
9 Geographical area of an EU Although there is no upper limit to the geographical area of an EU, the following considerations should be taken into account when combining IUs:The probability that foci of infection will be missed increases as the geographical area of the EU increases.Covering a larger area during the survey may increase logistical requirements (e.g. transport costs).
10 ExerciseUsing existing data (e.g. maps, list of IUs, population sizes, number of rounds of MDA and coverage).Define an appropriate EU(s).Note: Some of the data will have been reported on the ‘ELIGIBILITY’ worksheet of the TAS Eligibility and Reporting FormPresent the defined EU(s) to the group.
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