To assess virus dissemination following i.n. or i.o. inoculation, three ferrets per group were inoculated with indicated viruses and euthanized 3 days p.i. for postmortem examination and collection of tissues for virus titration as previously described [29] . Tissue specimens were collected for virus titration were immediately frozen on dry ice and stored at 270uC until processed. Blood samples collected during necropsy were subjected to complete blood counts (CBCs) and serum chemistry analyses performed per manufacturer's instructions as previously described [56] .