RHDV and RHDVa replication, excretion and tissue distribution in rabbit kittens infected with a high dose of inoculum. Shown are virus genome copy numbers per μl whole blood (A, B) or rectal swab (C, D) measured via RT-qPCR in samples taken from RHDV (A, C) and RHDVa (B, D) infected kittens 4–5 weeks of age at the indicated time points. SDL indicates the genome concentration relative to 20 genome copies detected in the RT-qPCR, which is considered the safe detection limit. E: Virus loads in tissues of RHDV and RHDVa infected kittens, 5 dpi. The safe detection limit of our assay in these tissues was 40 genome copies/mg on average (range: 35–71 depending on the amount of tissue the RNA was extracted from) or 12 genome copies/μl bile.