Remote sensing as a data source in a resource-limited context: species distribution modelling of invasive cattle ticks in West Africa

De Clercq, Eva M. [UCL] Vanwambeke, Sophie [UCL]

Approximately eight years ago, an exotic cattle tick from Latin America, Rhipicephalusmicroplus, invaded West Africa. Ad hoc sampling revealed that it has established viable populations in a few locations in Ivory Coast and through most of Benin.Because of the threat that R. microplus poses toanimal production,several research projects are working on an efficient control strategy, which is based on a map of current and potential distribution. This type of health mapping is part of a long-existing but currently re-emerging field of study that investigates the spatial dynamics of diseases and other health-related issues. Remote sensing and GIS have been essential instruments in this field. In this paper, we illustrate the contribution of environmental variables for disease management in the case of R. microplus, varying from the drafting of a sampling strategy to maps of areas at-risk of invasion for intensive monitoring. Individual Earth Observation images provide only very static information on tick habitat. Often, it is precisely the seasonality of temperature, humidity and vegetation which is important for vector development. NOAA’s AVHRR and more recently the MODIS sensor provide this data on a (bi) weekly basis and is an ideal source for tick distribution mapping. Of particular interest for further development are the EO data describing air temperature, humidity, vapour pressure deficit, and soil moisture. In order to be useful forepidemiological applications, this data needs to be available easily and in a standardised manner over large areas, and sufficiently detailed in terms of both spatial and temporal resolution.