title: The major portal of entry of koi herpesvirus in Cyprinus carpio is the skin.
abstract: Koi herpesvirus (KHV), recently designated Cyprinid herpesvirus 3, is the causative agent of a lethal disease in koi and common carp. In the present study, we investigated the portal of entry of KHV in carp by using bioluminescence imaging. Taking advantage of the recent cloning of the KHV genome as a bacterial artificial chromosome (BAC), we produced a recombinant plasmid encoding a firefly luciferase (LUC) expression cassette inserted in the intergenic region between open reading frame (ORF) 136 and ORF 137. Two viral strains were then reconstituted from the modified plasmid, the FL BAC 136 LUC excised strain and the FL BAC 136 LUC TK revertant strain, including a disrupted and a wild-type thymidine kinase (TK) locus, respectively. In vitro, the two recombinant strains replicated comparably to the parental FL strain. The FL BAC 136 LUC TK revertant strain was shown in vitro to induce a bioluminescent signal allowing the detection of single positive cells as early as 24 h postinfection, while in vivo, it induced KHV infection in carp that was indistinguishable from that induced by the parental FL strain. To identify the KHV portal of entry, carp were analyzed by bioluminescence imaging at different times postinfection with the FL BAC 136 LUC TK revertant strain. These analyses demonstrated that the skin of the fish covering the fins and also the body is the major portal of entry for KHV in carp. Finally, to further demonstrate the role of the skin as the KHV portal of entry, we constructed an original system, nicknamed "U-tube," to perform percutaneous infection restricted to the posterior part of the fish. All the data obtained in the present study demonstrate that the skin, and not the gills, is the major portal of entry for KHV in carp.
authors.affiliation: Immunology-Vaccinology (B43b), Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Costes
authors.forename: V Stalin
authors.initials: VS
authors.lastname: Raj
authors.forename: B
authors.initials: B
authors.lastname: Michel
authors.forename: G
authors.initials: G
authors.lastname: Fournier
authors.forename: M
authors.initials: M
authors.lastname: Thirion
authors.forename: L
authors.initials: L
authors.lastname: Gillet
authors.forename: J
authors.initials: J
authors.lastname: Mast
authors.forename: F
authors.initials: F
authors.lastname: Lieffrig
authors.forename: M
authors.initials: M
authors.lastname: Bremont
authors.forename: A
authors.initials: A
authors.lastname: Vanderplasschen
mesh_terms: D000818:Animals; D002347:Carps / Q000821:virology*; D005393:Fish Diseases / Q000821:virology*; D017930:Genes, Reporter; D006564:Herpesviridae / Q000235:genetics; D006566:Herpesviridae Infections / Q000662:veterinary* / Q000821:virology; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D012867:Skin / Q000821:virology*; D051598:Whole Body Imaging / Q000379:methods
chemical_list: D008164:Luminescent Proteins