title: No evidence of African swine fever virus replication in hard ticks.
abstract: African swine fever (ASF) is caused by African swine fever virus (ASFV), a tick-borne DNA virus. Soft ticks of the genus Ornithodoros are the only biological vectors of ASFV recognized so far. Although other hard ticks have been tested for vector competence, two commonly found tick species in Europe, Ixodes ricinus and Dermacentor reticulatus, have not been assessed for their vector competence for ASFV. In this study, we aimed to determine whether virus replication can occur in any of these two hard tick species (I. ricinus and/or D. reticulatus), in comparison with O. moubata (the confirmed vector), after feeding them blood containing different ASFV isolates using an improved in vitro system. DNA quantities of ASFV in these infected hard ticks were measured systematically, for 6 weeks in I. ricinus, and up to 8 weeks in D. reticulatus, and the results were compared to those obtained from O. moubata. There was evidence of virus replication in the O. moubata ticks. However, there was no evidence of virus replication in I. ricinus or D. reticulatus, even though viral DNA could be detected for up to 8 weeks after feeding in some cases. This study presents the first results on the possible vector competence of European hard (ixodid) ticks for ASFV, in a validated in vitro feeding setup. In conclusion, given the lack of evidence for virus replication under in vitro conditions, D. reticulatus and I. ricinus are unlikely to be relevant biological vectors of ASFV.
authors: Virology Department, Central Veterinary Institute, Part of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands; Farm Animal Department, Faculty of Veterinary Medicine, University Utrecht, Yalelaan 7-9, 3584 CL Utrecht, The Netherlands. Electronic address: helena.c.c.ferreira@gmail.com.
authors: Helena C
authors: HC
authors: de Carvalho Ferreira
authors: Utrecht Centre for Tick-borne Diseases (UCTD), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
authors: Sara
authors: S
authors: Tudela Zúquete
authors: Utrecht Centre for Tick-borne Diseases (UCTD), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
authors: Michiel
authors: M
authors: Wijnveld
authors: Virology Department, Central Veterinary Institute, Part of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands.
authors: Eefke
authors: E
authors: Weesendorp
authors: Utrecht Centre for Tick-borne Diseases (UCTD), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands; Department of Veterinary Tropical Diseases, Faculty of Veterinary Sciences, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors: Frans
authors: F
authors: Jongejan
authors: Farm Animal Department, Faculty of Veterinary Medicine, University Utrecht, Yalelaan 7-9, 3584 CL Utrecht, The Netherlands.
authors: Arjan
authors: A
authors: Stegeman
authors: Virology Department, Central Veterinary Institute, Part of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands. Electronic address: willie.loeffen@wur.nl.
authors: Willie L A
authors: WL
authors: Loeffen
mesh_terms: D000358:African Swine Fever Virus / Q000502:physiology*; D000818:Animals; D003870:Dermacentor / Q000821:virology*; D005260:Female; D018884:Ixodes / Q000821:virology*; D008297:Male; D026861:Ornithodoros / Q000821:virology*; D013045:Species Specificity; D014779:Virus Replication / Q000502:physiology*
keywords: African swine fever virus; Dermacentor reticulatus; In vitro feeding; Ixodes ricinus