title: Spatial and Functional Organization of Pig Trade in Different European Production Systems: Implications for Disease Prevention and Control.
abstract: Understanding the complexity of live pig trade organization is a key factor to predict and control major infectious diseases, such as classical swine fever (CSF) or African swine fever (ASF). Whereas the organization of pig trade has been described in several European countries with indoor commercial production systems, little information is available on this organization in other systems, such as outdoor or small-scale systems. The objective of this study was to describe and compare the spatial and functional organization of live pig trade in different European countries and different production systems. Data on premise characteristics and pig movements between premises were collected during 2011 from Bulgaria, France, Italy, and Spain, which swine industry is representative of most of the production systems in Europe (i.e., commercial vs. small-scale and outdoor vs. indoor). Trade communities were identified in each country using the Walktrap algorithm. Several descriptive and network metrics were generated at country and community levels. Pig trade organization showed heterogeneous spatial and functional organization. Trade communities mostly composed of indoor commercial premises were identified in western France, northern Italy, northern Spain, and north-western Bulgaria. They covered large distances, overlapped in space, demonstrated both scale-free and small-world properties, with a role of trade operators and multipliers as key premises. Trade communities involving outdoor commercial premises were identified in western Spain, south-western and central France. They were more spatially clustered, demonstrated scale-free properties, with multipliers as key premises. Small-scale communities involved the majority of premises in Bulgaria and in central and Southern Italy. They were spatially clustered and had scale-free properties, with key premises usually being commercial production premises. These results indicate that a disease might spread very differently according to the production system and that key premises could be targeted to more cost-effectively control diseases. This study provides useful epidemiological information and parameters that could be used to design risk-based surveillance strategies or to more accurately model the risk of introduction or spread of devastating swine diseases, such as ASF, CSF, or foot-and-mouth disease.
authors: Le Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), UPR Animal and Integrated Risk Management (AGIRs), Montpellier, France; Center for Animal Disease Modeling and Surveillance (CADMS), Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
authors: Anne
authors: A
authors: Relun
authors: Le Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), UPR Animal and Integrated Risk Management (AGIRs) , Montpellier , France.
authors: Vladimir
authors: V
authors: Grosbois
authors: Animal Health Department, Complutense University of Madrid , Madrid , Spain.
authors: José Manuel
authors: JM
authors: Sánchez-Vizcaíno
authors: Bulgarian Food Safety Agency , Sofia , Bulgaria.
authors: Tsviatko
authors: T
authors: Alexandrov
authors: Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche , Perugia , Italy.
authors: Francesco
authors: F
authors: Feliziani
authors: Institut National Polytechnique-Ecole Nationale Vétérinaire de Toulouse (INP-ENVT) , Toulouse , France.
authors: Agnès
authors: A
authors: Waret-Szkuta
authors: Le Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), UPR Animal and Integrated Risk Management (AGIRs) , Montpellier , France.
authors: Sophie
authors: S
authors: Molia
authors: Le Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), UPR Animal and Integrated Risk Management (AGIRs), Montpellier, France; Center for Animal Disease Modeling and Surveillance (CADMS), Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
authors: Eric Marcel Charles
authors: EM
authors: Etter
authors: Center for Animal Disease Modeling and Surveillance (CADMS), Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis , Davis, CA , USA.
authors: Beatriz
authors: B
authors: Martínez-López
keywords: community; infectious diseases; movements; network analysis; risk-based surveillance; swine