Virus genome copy numbers in samples from rabbit kittens inoculated with heat inactivated RHDV. Kittens were inoculated with 1 ml heat-inactivated (hi) RHDV containing 9x10e8 genome copies (equivalent to 2000 ID50). Kittens were sampled daily until autopsied at day 5. A: Virus genome copy numbers per μl blood; B: Genome copy numbers in rectal swab samples. SDL indicates the genome concentration relative to 20 genome copies detected in the RT-qPCR reaction, which is considered the safe detection limit.