Replication of the RG Mal/01 in mice and ferrets. (A) Four five-week-old BALB/c mice were infected under isoflurane anesthesia with 5 × 105TCID50/50 μl of RGMal/01. Body weight was measured for 14 days after infection. Body weight was compared with the body weight on day "0" before infection. (B) Three ferrets were inoculated i.n. with 5 × 105TCID50 of RGMal/01. Twenty-four hours later, one naïve ferret was added to the same cage as each of the infected ferrets. Viral titers were measured in nasal washes collected daily and were titrated in MDCK cells. The titers are expressed as log10 numbers of TCID50/ml. The detection limit is 0.699 log10TCID50/ml.