title: DIFFERENT SEROLOGICAL PROFILES TO CO-OCCURRING PATHOGENIC AND NONPATHOGENIC CALICIVIRUSES IN WILD EUROPEAN RABBITS (ORYCTOLAGUS CUNICULUS) ACROSS AUSTRALIA.
abstract: Rabbit hemorrhagic disease virus (RHDV) was released in Australia as a biocontrol agent for wild European rabbits ( Oryctolagus cuniculus ) in 1995-96; however, its effects were variable across Australia with the greatest population reductions seen in lower annual rainfall areas (<400 mm). There is speculation that the reduced effectiveness observed at higher annual rainfall sites is at least partially due to the presence of a nonpathogenic calicivirus (RCV-A1). The RCV-A1 is related to RHDV and confers partial and transient protection against lethal RHDV infection in laboratory tests. What is not well understood is where, how, and to what degree RCV-A1 impedes the effect of RHDV-mediated rabbit control under field conditions. We investigated seven wild rabbit populations across six states and territories representing different seasonal rainfall zones across Australia, four times during 2011-12, to investigate if the presence and prevalence of RCV-A1 coincided with a change in RHDV immunity status within these populations. Besides serology, tissue samples from both trapped and shot rabbits were collected for virus detection by reverse transcription PCR. Overall, 52% (n=258) of the total samples (n=496) tested positive for RHDV antibodies and 42% (n=208) positive for RCV-A1 antibodies; 30% (n=150) of the sera contained antibodies to both viruses. The proportion of rabbits with RHDV antibodies increased significantly at sites where RCV-A1 antibodies were present (χ21, α=0.1, P<0.001). Evidence that preinfection of RCV-A1 may lead to a higher proportion of sampled rabbits with antibodies to both viruses was found at only one site.
authors.affiliation: 1   New South Wales Department of Primary Industries, 1447 Forest Road, Orange NSW 2800, Australia.|2   Invasive Animals Cooperative Research Centre, UC Innovation Centre, Building 22, University Drive S, University of Canberra, Bruce ACT 2617, Australia.
authors.forename: Tarnya E
authors.initials: TE
authors.lastname: Cox
authors.affiliation: 3   Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Building 101, Clunies Ross Street, Black Mountain, Acton ACT 2601, Australia.
authors.forename: June
authors.initials: J
authors.lastname: Liu
authors.affiliation: 1   New South Wales Department of Primary Industries, 1447 Forest Road, Orange NSW 2800, Australia.
authors.forename: Remy van
authors.initials: RV
authors.lastname: de Ven
authors.affiliation: 2   Invasive Animals Cooperative Research Centre, UC Innovation Centre, Building 22, University Drive S, University of Canberra, Bruce ACT 2617, Australia.|3   Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Building 101, Clunies Ross Street, Black Mountain, Acton ACT 2601, Australia.
authors.forename: Tanja
authors.initials: T
authors.lastname: Strive
mesh_terms: D000818:Animals; D001315:Australia; D017250:Caliciviridae Infections / Q000662:veterinary*; D017929:Hemorrhagic Disease Virus, Rabbit / Q000302:isolation & purification* / Q000472:pathogenicity; D011157:Population Dynamics; D011817:Rabbits / Q000821:virology*
keywords: Biocontrol; RHDV; disease; epidemiology; introduced; resistance; wildlife