title: A Spatio-temporal Model of African Animal Trypanosomosis Risk.
abstract: BACKGROUND
  African animal trypanosomosis (AAT) is a major constraint to sustainable development of cattle farming in sub-Saharan Africa. The habitat of the tsetse fly vector is increasingly fragmented owing to demographic pressure and shifts in climate, which leads to heterogeneous risk of cyclical transmission both in space and time. In Burkina Faso and Ghana, the most important vectors are riverine species, namely Glossina palpalis gambiensis and G. tachinoides, which are more resilient to human-induced changes than the savannah and forest species. Although many authors studied the distribution of AAT risk both in space and time, spatio-temporal models allowing predictions of it are lacking.
  
  
  RESULTS
  We used datasets generated by various projects, including two baseline surveys conducted in Burkina Faso and Ghana within PATTEC (Pan African Tsetse and Trypanosomosis Eradication Campaign) national initiatives. We computed the entomological inoculation rate (EIR) or tsetse challenge using a range of environmental data. The tsetse apparent density and their infection rate were separately estimated and subsequently combined to derive the EIR using a "one layer-one model" approach. The estimated EIR was then projected into suitable habitat. This risk index was finally validated against data on bovine trypanosomosis. It allowed a good prediction of the parasitological status (r2 = 67%), showed a positive correlation but less predictive power with serological status (r2 = 22%) aggregated at the village level but was not related to the illness status (r2 = 2%).
  
  
  CONCLUSIONS
  The presented spatio-temporal model provides a fine-scale picture of the dynamics of AAT risk in sub-humid areas of West Africa. The estimated EIR was high in the proximity of rivers during the dry season and more widespread during the rainy season. The present analysis is a first step in a broader framework for an efficient risk management of climate-sensitive vector-borne diseases.
authors.affiliation: West African Science Service on Climate Change and Adapted Land Use, Climate Change Economics Research Program, Cheikh Anta Diop University, Dakar-Fann, Sénégal.
authors.forename: Ahmadou H
authors.initials: AH
authors.lastname: Dicko
authors.affiliation: The Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC), Bobo-Dioulasso, Burkina Faso.
authors.forename: Lassane
authors.initials: L
authors.lastname: Percoma
authors.affiliation: Ecole Inter Etats des Sciences et Médecine Vétérinaires de Dakar (EISMV), Dakar, Sénégal.
authors.forename: Adama
authors.initials: A
authors.lastname: Sow
authors.affiliation: Veterinary Services Department of the Ministry of Food and Agriculture, Pong-Tamale, Ghana.
authors.forename: Yahaya
authors.initials: Y
authors.lastname: Adam
authors.affiliation: Veterinary Services Department of the Ministry of Food and Agriculture, Pong-Tamale, Ghana.
authors.forename: Charles
authors.initials: C
authors.lastname: Mahama
authors.affiliation: The Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC), Bobo-Dioulasso, Burkina Faso; Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso.
authors.forename: Issa
authors.initials: I
authors.lastname: Sidibé
authors.affiliation: The Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC), Bobo-Dioulasso, Burkina Faso; Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso.
authors.forename: Guiguigbaza-Kossigan
authors.initials: GK
authors.lastname: Dayo
authors.affiliation: CIRAD, UMR INTERTRYP, Montpellier, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Thévenon
authors.affiliation: West African Science Center on Climate Change and Adapted Land Use, Ouagadougou, Burkina Faso.
authors.forename: William
authors.initials: W
authors.lastname: Fonta
authors.affiliation: West African Science Center on Climate Change and Adapted Land Use, Ouagadougou, Burkina Faso.
authors.forename: Safietou
authors.initials: S
authors.lastname: Sanfo
authors.affiliation: Direction Nationale des Services Vétérinaires, Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC), Mali, Bamako, Mali.
authors.forename: Aligui
authors.initials: A
authors.lastname: Djiteye
authors.affiliation: Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso; Université Polytechnique de Bobo Dioulasso (UPB), Bobo Dioulasso, Burkina Faso.
authors.forename: Ernest
authors.initials: E
authors.lastname: Salou
authors.affiliation: Felix Houphouet Boigny University, National Institute of Public Health, Abidjan, Côte d'Ivoire.
authors.forename: Vincent
authors.initials: V
authors.lastname: Djohan
authors.affiliation: Food and Agriculture Organization of the United Nations (FAO), Sub-regional Office for Eastern Africa, Addis Ababa, Ethiopia.
authors.forename: Giuliano
authors.initials: G
authors.lastname: Cecchi
authors.affiliation: CIRAD, UMR INTERTRYP, Montpellier, France; CIRAD, UMR CMAEE, Dakar-Hann, Sénégal; CIRAD, UMR CMAEE, Montpellier, France; INRA, UMR1309 CMAEE, Montpellier, France; Institut Sénégalais de Recherches Agricoles (ISRA), Laboratoire National d'Elevage et de Recherches Vétérinaires (LNERV), LNERV, Dakar-Hann, Sénégal.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Bouyer
mesh_terms: D000349:Africa / Q000453:epidemiology; D000818:Animals; D002417:Cattle; D017753:Ecosystem; D007303:Insect Vectors / Q000469:parasitology* / Q000502:physiology; D008962:Models, Theoretical; D012307:Risk Factors; D012621:Seasons; D014354:Trypanosomiasis, Bovine / Q000453:epidemiology* / Q000469:parasitology / Q000635:transmission; D014370:Tsetse Flies / Q000469:parasitology* / Q000502:physiology