Landscape attributes driving avian influenza virus circulation in the Lake Alaotra region of Madagascar

Guerrini, Laure and Paul, Mathilde C. and Leger, Lucas and Andriamanivo, Harentsoaniaina R. and Maminiaina, Olivier F. and Jourdan, Marion and Molia, Sophie and Rakotondravao, René and Chevalier, Véronique (2014) Landscape attributes driving avian influenza virus circulation in the Lake Alaotra region of Madagascar. Geospatial Health, 8 (2). pp. 445-453. ISSN 1970-7096

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While the spatial pattern of the highly pathogenic avian influenza H5N1 virus has been studied throughout Southeast Asia, little is known on the spatial risk factors for avian influenza in Africa. In the present paper, we combined serological data from poultry and remotely sensed environmental factors in the Lake Alaotra region of Madagascar to explore for any association between avian influenza and landscape variables. Serological data from cross-sectional surveys carried out on poultry in 2008 and 2009 were examined together with a Landsat 7 satellite image analysed using supervised classification. The dominant landscape features in a 1-km buffer around farmhouses and distance to the closest water body were extracted. A total of 1,038 individual bird blood samples emanating from 241 flocks were analysed, and the association between avian influenza seroprevalence and these landcape variables was quantified using logistic regression models. No evidence of the presence of H5 or H7 avian influenza subtypes was found, suggesting that only low pathogenic avian influenza (LPAI) circulated. Three predominant land cover classes were identified around the poultry farms: grassland savannah, rice paddy fields and wetlands. A significant negative relationship was found between LPAI seroprevalence and distance to the closest body of water. We also found that LPAI seroprevalence was higher in farms characterised by predominant wetlands or rice landscapes than in those surrounded by dry savannah. Results from this study suggest that if highly pathogenic avian influenza H5N1 virus were introduced in Madagascar, the environmental conditions that prevail in Lake Alaotra region may allow the virus to spread and persist

Item Type: Article
Uncontrolled Keywords: Avian influenza, epidemiology, remote sensing, spatial analysis, risk factors, landscape, Madagascar
Subjects: 600 Tecnologia - Scienze applicate > 610 Medicina e salute (Classificare qui la tecnologia dei servizi medici) > 614 Medicina legale; incidenza delle malattie; Medicina preventiva pubblica > 614.4 Incidenza delle malattie e misure pubblica per prevenirle (classificare qui l'Epidemiologia, l'Epidemiologia clinica)
Depositing User: Chiara D'Arpa
Date Deposited: 29 Jul 2014 15:48
Last Modified: 29 Jul 2014 15:48

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