Course and transmission characteristics of oral low-dose infection of domestic pigs and European wild boar with a Caucasian African swine fever virus isolate
- 582 Downloads
In 2007, African swine fever virus (ASFV) was introduced into the Transcaucasian countries and Russia. Since then, it has spread alarmingly and reached the European Union. ASFV strains are highly virulent and lead to almost 100 % mortality under experimental conditions. However, the possibility of dose-dependent disease courses has been discussed. For this reason, a study was undertaken to assess the risk of chronic disease and the establishment of carriers upon low-dose oronasal infection of domestic pigs and European wild boar. It was demonstrated that very low doses of ASFV are sufficient to infect especially weak or runted animals by the oronasal route. Some of these animals did not show clinical signs indicative of ASF, and they developed almost no fever. However, no changes were observed in individual animal regarding the onset, course and outcome of infection as assessed by diagnostic tests. After amplification of ASFV by these animals, pen- and stablemates became infected and developed acute lethal disease with similar characteristics in all animals. Thus, we found no indication of prolonged or chronic individual courses upon low-dose infection in either species. The scattered onset of clinical signs and pathogen detection within and among groups confirms moderate contagiosity that is strongly linked with blood contact. In conclusion, the prolonged course at the “herd level” together with the exceptionally low dose that proved to be sufficient to infect a runted wild boar could be important for disease dynamics in wild-boar populations and in backyard settings.
KeywordsWild Boar Basic Reproduction Number African Swine Fever African Swine Fever Virus Wild Boar Population
We would like to thank all animal caretakers and technicians involved in this study for their excellent work. We are also very grateful to William Gilbert for improving the readability of this paper. This work was carried out as part of the European Union–funded project ASFORCE (Seventh Framework Programme, FP7/2007-2013, under Grant Agreement no. 311931).
- 1.Sánchez-Vizcaíno JM, Martínez-López B, Martínez-Avilés M, Martins C, Boinas F, Vial L, Michaud V, Jori F, Etter E, Albina E, Roger F (2009) Scientific review on African swine fever. EFSA Scientific Report, pp 1–141Google Scholar
- 4.Carrascosa AL, Bustos MJ, de Leon P (2011) Methods for growing and titrating African swine fever virus: field and laboratory samples. In: Bonifacino JS et al (eds) Current protocols in cell biology, chapter 26, unit 26, p 14Google Scholar
- 5.Costard S, Jones BA, Martinez-Lopez B, Mur L, de la Torre A, Martinez M, Sanchez-Vizcaino F, Sanchez-Vizcaino JM, Pfeiffer DU, Wieland B (2013) Introduction of African swine fever into the European Union through illegal importation of pork and pork products. PLoS ONE 8:e61104PubMedCentralPubMedCrossRefGoogle Scholar
- 13.Howey EB, O’Donnell V, Ferreira HCdC, Borca MV, Arzt J (2013) Pathogenesis of highly virulent African swine fever virus in domestic pigs exposed via intraoropharyngeal, intranasopharyngeal, and intramuscular inoculation, and by direct contact with infected pigs. Virus Res 178:328–329PubMedCrossRefGoogle Scholar
- 14.Khomenko S, Beltrán-Alcrudo D, Rozstalnyy A, Gogin A, Kolbasov D, Pinto J, Lubroth J, Martin V (2013) African swine fever in the Russian Federation: risk factors for Europe and beyond. EMPRES WatchGoogle Scholar
- 27.Rowlands RJ, Michaud V, Heath L, Hutchings G, Oura C, Vosloo W, Dwarka R, Onashvili T, Albina E, Dixon LK (2008) African swine fever virus isolate, Georgia, 2007. Emerg Infect Dis, CDC, pp 1870–1874Google Scholar
- 29.Sanchez-Vizcaino JM (2006) African swine fever. Diseases of Swine. Blackwell Publishing, pp 291–298Google Scholar
- 30.Takamatsu HD, Dixon LK, Alonso C, Escribano JM, Martins C, Revilla Y, Salas ML (2011) Asfarviridae. Virus taxonomy, pp 153–162Google Scholar
- 31.Vynnycky E, White R (2010) An introduction to infectious disease modelling, 1st edn. Oxford University Press, New YorkGoogle Scholar