Pathogenic lagoviruses (Rabbit hemorrhagic disease virus, RHDV) are widely spread across the world and are used in Australia and New Zealand to control populations of feral European rabbits. The spread of the non-pathogenic lagoviruses, e.g., rabbit calicivirus (RCV), is less well studied as the infection results in no clinical signs. Nonetheless, RCV has important implications for the spread of RHDV and rabbit biocontrol as it can provide varying levels of cross-protection against fatal infection with pathogenic lagoviruses. In Chile, where European rabbits are also an introduced species, myxoma virus was used for localised biocontrol of rabbits in the 1950s. To date, there have been no studies investigating the presence of lagoviruses in the Chilean feral rabbit population. In this study, liver and duodenum rabbit samples from central Chile were tested for the presence of lagoviruses and positive samples were subject to whole RNA sequencing and subsequent data analysis. Phylogenetic analysis revealed a novel RCV variant in duodenal samples that likely originated from European RCVs. Sequencing analysis also detected the presence of a rabbit astrovirus in one of the lagovirus-positive samples.

Gene drives are transmission distorters that can transmit specific alleles to >90% of the progeny, e.g., the naturally occurring t-haplotype in mice. The hypothesised mechanism involves biased allele expression with impaired transcript sharing between developing spermatids. For invasive pest species, there is interest in co-opting naturally occurring gene drives. It is unknown whether similar natural gene drives exist in the European rabbit, a detrimental pest species in Australia. Here, we analysed the allele-specific expression (ASE) in rabbit spermatids to identify candidate genes for future investigation in genetic biocontrol applications. We utilised short-read and long-read technologies and performed a comparative analysis. Illumina sequencing was deemed unsuitable, whereas both long-read sequencing platforms demonstrated similar performance. The SPINK2 gene that plays an important role in fertility, consistently showed ASE towards one of the alleles. Furthermore, two kinases displayed bimodal allele expression. Future work is warranted to assess suitability of these genes for genetic biocontrol.

The ongoing circulation of pathogenic rabbit haemorrhagic disease viruses (RHDV1 and RHDV2) worldwide makes vaccination of domestic rabbits essential. Most commercially available RHDV vaccines are prepared by inactivating virus purified from the tissues of infected rabbits. Although highly effective, the production of such vaccines requires the use of rabbits in both manufacturing and quality assurance, raising ethical concerns. Inactivated cell culture-derived vaccines for RHDVs have not been described, as RHDV could not be grown reliably in vitro since its discovery. A recently developed rabbit liver-derived cell culture system supports RHDV replication to high titres, providing opportunities to explore development of a cell culture-based vaccine. Here, we compared a commercially available vaccine with an experimental RHDV2 vaccine derived from culture-grown virus. All rabbits, vaccinated with either formulation, survived RHDV2 challenge. These preliminary results demonstrate the potential of the RHDV culture system as an alternative platform for RHDV vaccine production.