Fig 1. Serial passaging of RHDV in adult rabbits.
Rabbits were infected orally with 1 × 105−2 × 108 capsid gene copies of RHDV. All rabbits within a passage received the same inoculum dose but the dose varied between passages. The RHDV-specific monoclonal antibody (mab 1H3) was administered intravenously 18−24 hours post-infection. Control animals were infected with RHDV but did not receive antibody injections. Rabbits were euthanised 3−4 days post-infection or when signs of terminal RHD were detected. A single animal from each passage (marked in red) was selected for the production of a new virus stock. Individual mab doses (μg/kg) are specified next to the rabbit outlines and virus titres in the liver, as quantified by qRT-PCR (capsid gene copies/mg liver tissue), are given inside rabbit drawings.