Infectious virus and WNV RNA were isolated from at least one tissue in all mice at 1 mo p.i..

− negative, + positive.
1Skin at the inoculation site consisted of the left rear footpad.
2Distal skin sites consisted of right rear footpad and both front footpads.
3Lymph nodes consisted of both popliteal and both inguinal lymph nodes.
4WNV was isolated on fourth pass.
Adult, female B6 mice were inoculated s.c. in the left rear footpad with diluent alone (mock) or with 103 PFU of WNV. Mice were sacrificed at 1 mo p.i., and WNV infection was confirmed in all WNV-inoculated mice by seroconversion. Eight tissues per mouse were harvested for virus isolation and RT-PCR for WNV. Virus isolation was performed on eight tissues per mouse by co-culturing the homogenized tissues on Vero cell monolayers. All samples were passed at least two more times onto fresh monolayers, and tissue culture supernatants from the third passage were tested for the presence of WNV by RT-PCR. Mouse #90 was sick during acute phase of disease (7 to 14 days p.i.). All other mice did not show any clinical disease.