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No evidence of rabbit haemorrhagic disease virus 2 infection in scavengers of wild rabbits in Australia

Ina Smith , Nina Huang, Megan Pavy, Alexander Gofton, Omid Fahri, Egi Kardia, Roslyn Mourant, Sammi Chong, Maria Jenckel, Robyn Hall, Tanja Strive

Abstract

Context Rabbit haemorrhagic disease virus 2 (RHDV2/b/ GI.2) is the only representative of the genus Lagovirus that is known to fatally infect multiple lagomorph species. RHDV2 is the dominant lagovirus circulating in rabbits in Australia, where some lagoviruses are used for deliberate biological control of European rabbits, a major environmental and agricultural pest in this country. Evidence of exposure to lagoviruses has been reported for a range of species that feed on rabbits, and the reduced host specificity of RHDV2 compared to RHDV1 has occasionally raised concerns, especially in a biocontrol context. Aim We investigated evidence of exposure to RHDV2 in 99 individual feral foxes, cats, dogs and pigs and then we aimed to test these animals for evidence of a productive infection. Methods Sera were analysed for the presence of antibodies to RHDV2, and faeces and tissues for the presence of viral RNA. We made provisions for downstream analysis of liver tissues by RT-qPCR and histopathology should they return a positive RT-qPCR result, to further investigate any evidence of productive virus infection. We also infected RHDV2 in hepatobiliary organoids derived from cats and foxes to test for possible infection. Key results We detected serum antibodies and viral RNA in faeces indicative of ingestion of RHDV2-infected rabbits but found no evidence for productive infection with RHDV2. Furthermore, no RHDV2 replication was seen in hepatobiliary organoids derived from foxes and cats after in vitro infection with RHDV2. Conclusion RHDV2 does not infect scavengers of rabbits, such as foxes, dogs, cats and pigs. Implications This study provides insights into the safety of this strain.

WR24122  Accepted 17 December 2024

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