Rabbit haemorrhagic disease: Cross-protection and comparative pathogenicity of GI.2/RHDV2/b and GI.1b/RHDV lagoviruses in a challenge trial

Abstract European rabbits ( Oryctolagus cuniculus ) are severely affected by rabbit haemorrhagic disease (RHD). Caused by a lagovirus, the disease leads to losses in the rabbit industry and has implications for wildlife conservation. Past RHD outbreaks have been caused by GI.1/RHDV genotype viruses. A new virus belonging to the GI.2/RHDV2/b genotype emerged in 2010, quickly spreading and replacing the former in several countries; however, limited data are available on its pathogenicity and epidemiological factors. The present work extends these issues and evaluates cross-protection between both genotypes. Ninety-four and 88 domestic rabbits were challenged with GI.2/RHDV2/b and GI.1b/RHDV variant isolates, respectively. Cross-protection was determined by a second challenge on survivors with the corresponding strain. Mortality by GI.2/RHDV2/b was highly variable due to unknown individual factors, whereas mortality by GI.1b/RHDV was associated with age. Mortality in rabbits