Selection against domestication alleles in introduced rabbit populations.

Humans have moved domestic animals around the globe for thousands of years. These have occasionally established feral populations in nature, often with devastating ecological consequences. To understand how natural selection shapes re-adaptation into the wild, we investigated one of the most successful colonizers in history, the European rabbit.

First Detection and Circulation of RHDV2 in New Zealand.

Rabbit haemorrhage disease virus 2 (RHDV2) is a highly pathogenic lagovirus that causes lethal disease in rabbits and hares (lagomorphs). Since its first detection in Europe in 2010, RHDV2 has spread worldwide and has been detected in over 35 countries so far. Here, we provide the first detailed report of the detection and subsequent circulation of RHDV2 in New Zealand.

A single introduction of wild rabbits triggered the biological invasion of Australia.

Biological invasions are a major cause of environmental and economic disruption. While ecological factors are key determinants of their success, the role of genetics has been more challenging to demonstrate. The colonization of Australia by the European rabbit is one of the most iconic and devastating biological invasions in recorded history.

Age and Infectious Dose Significantly Affect Disease Progression after RHDV2 Infection in Naïve Domestic Rabbits.

Rabbit haemorrhagic disease virus 2 (RHDV2 or GI.2, referring to any virus with lagovirus GI.2 structural genes) is a recently emerged calicivirus that causes generalised hepatic necrosis and disseminated intravascular coagulation leading to death in susceptible lagomorphs (rabbits and hares).

Benign Rabbit Calicivirus in New Zealand.

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.

Benign Rabbit Caliciviruses Exhibit Evolutionary Dynamics Similar to Those of Their Virulent Relatives.

Unlabelled: Two closely related caliciviruses cocirculate in Australia: rabbit hemorrhagic disease virus (RHDV) and rabbit calicivirus Australia 1 (RCV-A1). RCV-A1 causes benign enteric infections in the European rabbit (Oryctolagus cuniculus) in Australia and New Zealand, while its close relative RHDV causes a highly pathogenic infection of the liver in the same host. The comparison of these viruses provides important information on the nature and trajectory of virulence evolution, particularly as highly virulent strains of RHDV may have evolved from nonpathogenic ancestors such as RCV-A1.

Resolving the Origin of Rabbit Hemorrhagic Disease Virus: Insights from an Investigation of the Viral Stocks Released in Australia.

To resolve the evolutionary history of rabbit hemorrhagic disease virus (RHDV), we performed a genomic analysis of the viral stocks imported and released as a biocontrol measure in Australia, as well as a global phylogenetic analysis. Importantly, conflicts were identified between the sequences determined here and those previously published that may have affected evolutionary rate estimates. By removing likely erroneous sequences, we show that RHDV emerged only shortly before its initial description in China.

Comparative Phylodynamics of Rabbit Hemorrhagic Disease Virus in Australia and New Zealand.

Unlabelled: The introduction of rabbit hemorrhagic disease virus (RHDV) into Australia and New Zealand during the 1990s as a means of controlling feral rabbits is an important case study in viral emergence. Both epidemics are exceptional in that the founder viruses share an origin and the timing of their release is known, providing a unique opportunity to compare the evolution of a single virus in distinct naive populations. We examined the evolution and spread of RHDV in Australia and New Zealand through a genome-wide evolutionary analysis, including data from 28 newly sequenced RHDV field isolates.

Rsx is a metatherian RNA with Xist-like properties in X-chromosome inactivation.

In female (XX) mammals, one of the two X chromosomes is inactivated to ensure an equal dose of X-linked genes with males (XY). X-chromosome inactivation in eutherian mammals is mediated by the non-coding RNA Xist. Xist is not found in metatherians (marsupials), and how X-chromosome inactivation is initiated in these mammals has been the subject of speculation for decades.

Vaccinia virus as a vaccine delivery system for marsupial wildlife.

Vaccines based on recombinant poxviruses have proved successful in controlling diseases such as rabies and plague in wild eutherian mammals. They have also been trialled experimentally as delivery agents for fertility-control vaccines in rodents and foxes. In some countries, marsupial mammals represent a wildlife disease reservoir or a threat to conservation values but, as yet there has been no bespoke study of efficacy or immunogenicity of a poxvirus-based vaccine delivery system in a marsupial.

Humoral immune responses in brushtail possums (Trichosurus vulpecula) induced by bacterial ghosts expressing possum zona pellucida 3 protein.

The introduced common brushtail possum (Trichosurus vulpecula) is a major pest in New Zealand and immunocontraceptive vaccines are being developed for biocontrol of possum populations, with bacterial ghosts (BGs) being evaluated as a means of oral delivery. Recombinant BGs expressing possum zona pellucida 3 protein (ZP3) as an L' membrane-anchored protein (ZP3-L') or as an S-layer SbsA-fusion protein (MBP-SbsA-ZP3) were produced by the expression of the cloned bacteriophage phiX174 lysis gene E in E. coli NM522.

Identification and evaluation of an infertility-associated ZP3 epitope from the marsupial brushtail possum (Trichosurus vulpecula).

Immunologically based fertility control vaccines against zona pellucida (ZP) proteins are being developed in New Zealand for biocontrol of the brushtail possum (Trichosurus vulpecula), an introduced Australian marsupial pest. We have shown that immunization of female possums with recombinant possum ZP3 protein (rZP3) reduced fertility by 79%. To enhance the specificity of possum immunocontraceptive vaccines, B-cell epitopes on possum ZP3 protein were mapped using sera of female possums immunized with possum rZP3 and subjected to a fertility trial.

MHC haplotypes and response to immunocontraceptive vaccines in the brushtail possum.

The possum is a major invasive pest in New Zealand. One option for its control is the use of immunocontraceptive vaccines. Initial trials of vaccines have shown individual variation in response.

Bacterial ghosts as a delivery system for zona pellucida-2 fertility control vaccines for brushtail possums (Trichosurus vulpecula).

The introduced brushtail possum is a serious pest in New Zealand and there is much interest in the development of an immunocontraceptive vaccine for population control. Immunisation of female possums against recombinant possum zona pellucida protein-2 (ZP2) is known to reduce embryo production by 72-75% but successful development of fertility control will depend on a delivery system that is effective for field use. Bacterial ghost vaccine technology is a promising system to formulate a non-living vaccine for bait or aerosol delivery.

Immunogenicity and contraceptive potential of three infertility-relevant zona pellucida 2 epitopes in the marsupial brushtail possum (Trichosurus vulpecula).

In a previous study, three infertility-relevant epitopes of possum ZP2 (Pep12 (amino acids 111-125), Pep31 (amino acids 301-315), and Pep44 (amino acids 431-445)) were identified using sera from possums (Trichosurus vulpecula) immunized with recombinant possum zona pellucida 2 (ZP2) constructs, and a synthetic peptide library of possum ZP2 protein. In this study, the three peptides were conjugated to keyhole limpet hemocyanin and 300 mug of each conjugated peptide were administered subcutaneously to female possums (n = 20 per peptide) in complete Freund's adjuvant. Immunogen doses were repeated 3 and 6 weeks later using incomplete Freund's adjuvant.

Plant-based immunocontraceptive control of wildlife--"potentials, limitations, and possums".

Possums (Trichosurus vulpecula), originally introduced from Australia, are spread over 90% of New Zealand and cause major economic and environmental damage. Immunocontraception has been suggested as a humane means to control them. Marsupial-specific reproductive antigens expressed at high levels in edible transgenic plant tissue might provide a safe, effective, and cheap oral delivery bait for immunocontraceptive control.

Mapping of B cell epitopes on the zona pellucida 2 protein of a marsupial, the brushtail possum (Trichosurus vulpecula).

Immunocontraceptive vaccines against zona pellucida (ZP) proteins are being developed for brushtail possum (Trichosurus vulpecula) management in New Zealand. Mapping of B cell epitopes on the ZP2 protein of possums was undertaken in this study to define the antigenic regions that may be crucial to sperm-egg binding. The amino acid sequence of the full-length possum ZP2 protein (712 amino acids) was used to synthesize a complete set of 71 (15-mer) biotinylated peptides with an offset of five amino acids.

Expression in Escherichia coli and immunological characterization of three zona pellucida proteins (ZP1, ZP2, and ZP3) from a marsupial, the brushtail possum (Trichosurus vulpecula).

The brushtail possum (Trichosurus vulpecula) zona pellucida (ZP) is composed of three major glycoproteins, designated ZP1, ZP2, and ZP3 based on their size and homology with eutherian ZP proteins. These proteins are candidate antigens for the development of an immunocontraceptive vaccine to control the fertility of the brushtail possum in New Zealand, where it is an introduced pest. In order to further their immunological and functional characterization, recombinant possum ZP proteins were produced in Escherichia coli (E.