title: Benign Rabbit Calicivirus in New Zealand.
abstract: The Czech v351 strain of rabbit hemorrhagic disease virus (RHDV1) is used in Australia and New Zealand as a biological control agent for rabbits, which are important and damaging introduced vertebrate pests in these countries. However, nonpathogenic rabbit caliciviruses (RCVs) can provide partial immunological cross-protection against lethal RHDV infection and thus interfere with effective rabbit biocontrol. Antibodies that cross-reacted against RHDV antigens were found in wild rabbits before the release of RHDV1 in New Zealand in 1997, suggesting that nonpathogenic RCVs were already present in New Zealand. The aim of this study was to confirm the presence of nonpathogenic RCV in New Zealand and describe its geographical distribution. RCV and RHDV antibody assays were used to screen serum samples from 350 wild rabbits from 14 locations in New Zealand. The serological survey indicated that both RCV and RHDV are widespread in New Zealand wild rabbits, with antibodies detected in 10 out of 14 and 12 out of 14 populations, respectively. Two closely related RCV strains were identified in the duodenal tissue from a New Zealand wild rabbit (RCV Gore-425A and RCV Gore-425B). Both variants are most closely related to Australian RCV strains, but with 88% nucleotide identity, they are genetically distinct. Phylogenetic analysis revealed that the New Zealand RCV strains fall within the genetic diversity of the Australian RCV isolates, indicating a relatively recent movement of RCVs between Australia and New Zealand.IMPORTANCEWild rabbits are important and damaging introduced vertebrate pests in Australia and New Zealand. Although RHDV1 is used as a biological control agent, some nonpathogenic RCVs can provide partial immunological cross-protection against lethal RHDV infection and thus interfere with its effectiveness for rabbit control. The presence of nonpathogenic RCVs in New Zealand wild rabbits has been long hypothesized, but earlier attempts to isolate a New Zealand RCV strain have been unsuccessful. Therefore, it is important to determine if such nonpathogenic viruses exist in New Zealand rabbits, especially considering the proposed introduction of new RHDV strains into New Zealand as biocontrols.
authors.affiliation: Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.|Wildlife Ecology and Management Group, Landcare Research, Lincoln, New Zealand.|Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, Canberra, Australian Capital Territory, Australia.
authors.forename: Leila J
authors.initials: LJ
authors.lastname: Nicholson
authors.affiliation: Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Black Mountain, Canberra, Australian Capital Territory, Australia.|Marie Bashir Institute for Infectious Disease and Biosecurity, School of Life and Environmental Sciences and Sydney Medical School, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Jackie E
authors.initials: JE
authors.lastname: Mahar
authors.affiliation: Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Black Mountain, Canberra, Australian Capital Territory, Australia.|Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, Canberra, Australian Capital Territory, Australia.
authors.forename: Tanja
authors.initials: T
authors.lastname: Strive
authors.affiliation: AgResearch Ltd., Hopkirk Research Institute, Grasslands Research Centre, Palmerston North, New Zealand.
authors.forename: Tao
authors.initials: T
authors.lastname: Zheng
authors.affiliation: Marie Bashir Institute for Infectious Disease and Biosecurity, School of Life and Environmental Sciences and Sydney Medical School, Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Edward C
authors.identifier: http://orcid.org/0000-0001-9596-3552
authors.initials: EC
authors.lastname: Holmes
authors.affiliation: Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Vernon K
authors.initials: VK
authors.lastname: Ward
authors.affiliation: Wildlife Ecology and Management Group, Landcare Research, Lincoln, New Zealand duckworthj@landcareresearch.co.nz.|Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, Canberra, Australian Capital Territory, Australia.
authors.forename: Janine A
authors.initials: JA
authors.lastname: Duckworth
mesh_terms: D000818:Animals; D017250:Caliciviridae Infections / Q000662:veterinary* / Q000821:virology; D005260:Female; D017929:Hemorrhagic Disease Virus, Rabbit / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D008297:Male; D009520:New Zealand; D010802:Phylogeny; D011817:Rabbits / Q000821:virology*
keywords: ELISA; RHDV; rabbit; rabbit calicivirus; virus discovery