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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Vet. Sci. | doi: 10.3389/fvets.2019.00376

Free-ranging pig and wild boar interactions in an endemic area of African swine fever

  • 1Complutense University of Madrid, Spain
  • 2Experimental Zooprophylactic Institute of Sardinia, Italy
  • 3Instituto de Investigación en Recursos Cinegéticos (IREC), Spain

African swine fever virus (ASFV) is spreading throughout Eurasia and there is no vaccine nor treatment available, so the control is based on the implementation of strict sanitary measures. These measures include depopulation of infected and in-contact animals and export restrictions, which can lead to important economic losses, making currently African swine fever (ASF) the greatest threat to the global swine industry. ASF has been endemic on the island of Sardinia since 1978, the longest persistence of anywhere in Eurasia. In Sardinia, eradication programs have failed, in large part due to the lack of farm professionalism, the high density of wild boar and the presence of non-registered domestic pigs (free-ranging pigs). In order to clarify how the virus is transmitted from domestic to wild swine, we examined the interaction between free-ranging pigs and wild boar in an ASF-endemic area of Sardinia. To this end, a field study was carried out on direct and indirect interactions, using monitoring by camera trapping in different areas and risk points. Critical time windows for the virus to survive in the environment (long window) and remain infectious (short window) were estimated, and based on these, the number of indirect interactions were determined. Free-ranging pigs indirectly interacted often with wild boar (long window = 6.47 interactions/day, short window =1.31 interactions/day) and these interactions (long window) were mainly at water sources. They also directly interacted 0.37 times per day, especially between 14:00 and 21:00 h, which is much higher than for other interspecific interactions observed in Mediterranean scenarios. The highly frequent interactions at this interspecific interface may help explain the more than four-decade-long endemicity of ASF on the island. Supporting that free-ranging pigs can act as a bridge to transmit ASFV between wild boar and registered domestic pigs. This study contributes broadly to improving the knowledge on the estimation of frequencies of direct and indirect interactions between wild and free-ranging domestic swine. As well as supporting the importance of the analysis of interspecific interactions in shared infectious diseases, especially for guiding disease management. Finally, this work illustrates the power of the camera-trapping method for analyzing interspecific interfaces.

Keywords: Interaction, Wild boar (<italic>Sus scrofa</italic>), Free ranging pigs, Camera trapping, critical time window, African Swine Fever

Received: 28 Jun 2019; Accepted: 11 Oct 2019.

Copyright: © 2019 Cadenas-Fernández, Sanchez-Vizcaino, Pintore, Denurra, Cherchi, Jurado, Vicente and Barasona. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Miss. Estefanía Cadenas-Fernández, Complutense University of Madrid, Madrid, Spain, estefania.cadenas@ucm.es