Collection of entomological baseline data in the mouhoun river basin (burkina faso): the use of Gis, remote sensing and Gps

This paper describes how geographic information system (GIS), remote sensing (RS) and Global Positioning System (GPS) technologies were used to plan the collection of entomological baseline data for a tsetse and trypanosomiasis (T&T) elimination project in the Mouhoun river basin in Burkina Faso. Historical data were collated as the background for data analysis. These data were used to define the survey area and to assess the probability of tsetse fly presence. Existing data and satellite images were used both to determine the sampling and trapping sites and to navigate to the areas used for deployment and release of the traps. For data management, a geodatabase (ArcGIS ArcInfo Desktop) and a relational database (MS Access) were created. The geodatabase was used to compile all geographical data, and the relational database served to integrate field data using a user-friendly interface for technicians. The methodologies and datasets presented in this paper represent essential prerequisites for subsequent project activities, including suppression and eradication of tsetse. introduCtion The distribution of tsetse and trypanosomiasis is determined mainly by habitat structure and vegetation types. Tsetse flies live in forests, savannah and riparian woodlands where vegetation provides a suitable climate and habitat for their survival and reproduction. Burkina Faso, like many other tsetse-infested countries in western Africa, suffers subsequent constraints on its agriculture and the livelihood of its rural populations. It is located on a plateau, with most of the country between 300 and 400 m in elevation. It consists of vast plains, broken by occasional low hills. Riverine forest vegetation is predominant in most areas infested by tsetse. The impact of landscape fragmentation on the structure and distribution of a population of Glossina palpalis gambiensis along the Mouhoun (Black Volta) river basin can be traced to human and climatic factors. Tsetse-transmitted trypanosomiasis is a unique and complex disease that requires strategic study at the continental level. Careful evaluation is necessary of the many different variables that exert a varying influence on its distribution and impact, both geographically and over time. For this reason, GIS, RS and GPS technologies provide powerful tools that can be used to measure a wide range of field parameters essential to sampling, surveys and T&T interventions. GIS has been used principally to predict Collection of entomological baseline data in the Mouhoun river basin (Burkina Faso) 54 the distribution and dynamics of different vectors (Lessard et al., 1990), and numerous digital georeferenced databases have been developed to accomplish different tasks. In Burkina Faso, GIS, RS and GPS technologies have been used to define the project area for the collection of entomological baseline data in the Mouhoun river basin and to assist in the implementation of the project to create sustainable T&T-free areas in western Africa under the Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC) initiative. projeCt area With the aid of GIS software, the project area was delineated using river basin maps, topographic maps and a map of tsetse fly distribution in Africa (FAO, 2000). The project area was divided into five blocks covering the Mouhoun river basin. The area of each block ranges from 10 000 to 30 000 km2. The survey area referred to in this paper is in Block I (Map 1). data-mining software used: arcGis arcinfo desktop 9.0, erdas imagine 8.4, ms access Three programs were used: ArcGIS ArcInfo Desktop 9.01, Erdas Imagine 8.4 and Microsoft Access2. The choice of these programs was made according to their individual capabilities and the compatibility among them. • ArcGIS ArcInfo Desktop is the most widely used GIS (i.e. vector-oriented) software; it is able to handle a geodatabase and has good compatibility with MS Access; • Erdas Imagine is image-processing software that is oriented to raster datasets, especially satellite imagery; its file format (.img) is easily readable in ArcGIS; • Microsoft Access is a relational database management system (RDBMS); for this project, it was used to build the database for storing and managing entomological data collected in the field. Importantly, these three programs are compatible with one another, which facilitated project data management. A key feature of ArcGIS ArcInfo Desktop is its ability to build geodatabases capable of integrating existing data. Various geographical layers in various formats were collected from different sources and subsequently loaded into ArcGIS geodatabases, which stored these layers as “Feature classes” grouped into “Feature datasets”. To fit the needs of the survey, two geodatabases were created: a base maps geodatabase and an entomological data geodatabase. base maps geodatabase Most of the data for the base maps geodatabase were obtained from the Institut Géographique du Burkina. They are in shapefile format in a WGS 84 zone 30 projection and include administrative boundaries, land use/land cover, rivers, etc. 1 http://www.esri.com 2 http://www.microsoft.com 55 Collection of entomological baseline data in the Mouhoun river basin (Burkina Faso)