title: Using remote sensing to map larval and adult populations of Anopheles hyrcanus (Diptera: Culicidae) a potential malaria vector in Southern France.
abstract: BACKGROUND
  Although malaria disappeared from southern France more than 60 years ago, suspicions of recent autochthonous transmission in the French Mediterranean coast support the idea that the area could still be subject to malaria transmission. The main potential vector of malaria in the Camargue area, the largest river delta in southern France, is the mosquito Anopheles hyrcanus (Diptera: Culicidae). In the context of recent climatic and landscape changes, the evaluation of the risk of emergence or re-emergence of such a major disease is of great importance in Europe. When assessing the risk of emergence of vector-borne diseases, it is crucial to be able to characterize the arthropod vector's spatial distribution. Given that remote sensing techniques can describe some of the environmental parameters which drive this distribution, satellite imagery or aerial photographs could be used for vector mapping.
  
  
  RESULTS
  In this study, we propose a method to map larval and adult populations of An. hyrcanus based on environmental indices derived from high spatial resolution imagery. The analysis of the link between entomological field data on An. hyrcanus larvae and environmental indices (biotopes, distance to the nearest main productive breeding sites of this species i.e., rice fields) led to the definition of a larval index, defined as the probability of observing An. hyrcanus larvae in a given site at least once over a year. Independent accuracy assessments showed a good agreement between observed and predicted values (sensitivity and specificity of the logistic regression model being 0.76 and 0.78, respectively). An adult index was derived from the larval index by averaging the larval index within a buffer around the trap location. This index was highly correlated with observed adult abundance values (Pearson r = 0.97, p < 0.05). This allowed us to generate predictive maps of An. hyrcanus larval and adult populations from the landscape indices.
  
  
  CONCLUSIONS
  This work shows that it is possible to use high resolution satellite imagery to map malaria vector spatial distribution. It also confirms the potential of remote sensing to help target risk areas, and constitutes a first essential step in assessing the risk of re-emergence of malaria in southern France.
authors.affiliation: Territories, Environment, Remote Sensing and Spatial Information Joint Research Unit (UMR TETIS), Maison de la Télédétection, 500 rue J,-F, Breton, 34093 Montpellier Cedex 5, France. annelise.tran@cirad.fr
authors.forename: Annelise
authors.initials: A
authors.lastname: Tran
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ponçon
authors.forename: Céline
authors.initials: C
authors.lastname: Toty
authors.forename: Catherine
authors.initials: C
authors.lastname: Linard
authors.forename: Hélène
authors.initials: H
authors.lastname: Guis
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Ferré
authors.forename: Danny
authors.initials: D
authors.lastname: Lo Seen
authors.forename: François
authors.initials: F
authors.lastname: Roger
authors.forename: Stéphane
authors.initials: S
authors.lastname: de la Rocque
authors.forename: Didier
authors.initials: D
authors.lastname: Fontenille
authors.forename: Thierry
authors.initials: T
authors.lastname: Baldet
mesh_terms: D000818:Animals; D000852:Anopheles / Q000254:growth & development* / Q000469:parasitology; D004772:Entomology; D004777:Environment; D004784:Environmental Monitoring / Q000379:methods; D005602:France; D005843:Geography; D007303:Insect Vectors / Q000254:growth & development; D007814:Larva / Q000254:growth & development* / Q000469:parasitology; D008288:Malaria / Q000469:parasitology*; D011157:Population Dynamics; D018531:Spacecraft