title: Ecological modeling of the spatial distribution of wild waterbirds to identify the main areas where avian influenza viruses are circulating in the Inner Niger Delta, Mali.
abstract: Predicting areas of disease emergence when no epidemiological data is available is essential for the implementation of efficient surveillance programs. The Inner Niger Delta (IND) in Mali is a major African wetland where >1 million Palearctic and African waterbirds congregate. Waterbirds are the main reservoir of Avian Influenza Viruses (AIV). Our objective was to model their spatial distribution in order to predict where these viruses would be more likely to circulate. We developed a generalized linear model (GLM) and a boosted regression trees (BRT) model based on total aerial bird counts taken in winter over 6 years. We used remotely sensed environmental variables with a high temporal resolution (10 days) to predict the spatial distribution of four waterbird groups. The predicted waterbird abundances were weighted with an epidemiological indicator based on the prevalence of low pathogenic AIV reported in the literature. The BRT model had the best predictive power and allowed prediction of the high variability of waterbird distribution. Years with low flood levels showed areas with a higher risk of circulation and had better spatial distribution predictions. Each year, the model identified a few areas with a higher risk of AIV circulation. This model can be applied every 10 days to evaluate the risk of AIV emergence in wild waterbirds. By taking into account the IND's ecological variability, it allows better targeting of areas considered for surveillance. This could enhance the control of emerging diseases at a local and regional scale, especially when resources available for surveillance programs are scarce.
authors.affiliation: CIRAD ES, UR Animal et Gestion intégrée des risques (AGIR), TA C 22/E, Campus International de Baillarguet, Montpellier, France. julien.cappelle@cirad.fr
authors.forename: Julien
authors.initials: J
authors.lastname: Cappelle
authors.forename: Olivier
authors.initials: O
authors.lastname: Girard
authors.forename: Bouba
authors.initials: B
authors.lastname: Fofana
authors.forename: Nicolas
authors.initials: N
authors.lastname: Gaidet
authors.forename: Marius
authors.initials: M
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D046090:Anseriformes / Q000821:virology*; D001717:Birds; D017753:Ecosystem; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology*; D008302:Mali / Q000453:epidemiology; D008954:Models, Biological; D011156:Population Density; D011157:Population Dynamics; D012044:Regression Analysis; D012307:Risk Factors; D045483:Rivers