title: The Potential Role of Direct and Indirect Contacts on Infection Spread in Dairy Farm Networks.
abstract: Animals' exchanges are considered the most effective route of between-farm infectious disease transmission. However, despite being often overlooked, the infection spread due to contaminated equipment, vehicles, or personnel proved to be important for several livestock epidemics. This study investigated the role of indirect contacts in a potential infection spread in the dairy farm network of the Province of Parma (Northern Italy). We built between-farm contact networks using data on cattle exchange (direct contacts), and on-farm visits by veterinarians (indirect contacts). We compared the features of the contact structures by using measures on static and temporal networks. We assessed the disease spreading potential of the direct and indirect network structures in the farm system by using data on the infection state of farms by paratuberculosis. Direct and indirect networks showed non-trivial differences with respect to connectivity, contact distribution, and super-spreaders identification. Furthermore, our analyses on paratuberculosis data suggested that the contributions of direct and indirect contacts on diseases spread are apparent at different spatial scales. Our results highlighted the potential role of indirect contacts in between-farm disease spread and underlined the need for a deeper understanding of these contacts to develop better strategies for prevention of livestock epidemics.
authors.affiliation: Dipartimento di Bioscienze, Università degli studi di Parma, Parco Area delle Scienze, Parma, Italy.|Risk Analysis Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via dei Mercati, Parma, Italy.
authors.forename: Gianluigi
authors.identifier: 0000-0002-6540-8467
authors.initials: G
authors.lastname: Rossi
authors.affiliation: Dipartimento di Bioscienze, Università degli studi di Parma, Parco Area delle Scienze, Parma, Italy.|Stanford University, Hopkins Marine Station, Pacific Grove, CA, United States of America.
authors.forename: Giulio A
authors.identifier: 0000-0002-4186-3369
authors.initials: GA
authors.lastname: De Leo
authors.affiliation: Risk Analysis Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via dei Mercati, Parma, Italy.
authors.forename: Stefano
authors.identifier: 0000-0002-4823-3562
authors.initials: S
authors.lastname: Pongolini
authors.affiliation: Servizio Veterinario e Igiene Alimenti, Assessorato Politiche per la Salute Regione Emilia-Romagna, Viale Aldo Moro, Bologna, Italy.
authors.forename: Silvano
authors.initials: S
authors.lastname: Natalini
authors.affiliation: Servizio Igiene degli Allevamenti e Produzioni Zootecniche, AUSL di Parma, Via Vasari, Parma, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Zarenghi
authors.affiliation: National Reference Centre for Paratuberculosis, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Strada Faggiola 1, loc. Gariga-Podenzano (PC), Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Ricchi
authors.affiliation: Risk Analysis Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via dei Mercati, Parma, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Bolzoni
mesh_terms: D000383:Agriculture / Q000706:statistics & numerical data*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology*; D003141:Communicable Diseases / Q000453:epidemiology* / Q000662:veterinary; D003198:Computer Simulation; D016358:Contact Tracing / Q000662:veterinary*; D003612:Dairying / Q000706:statistics & numerical data*; D004196:Disease Outbreaks / Q000706:statistics & numerical data / Q000662:veterinary*; D005260:Female; D015994:Incidence; D007558:Italy; D008297:Male; D015233:Models, Statistical; D012307:Risk Factors