Figure 4

Replication of VN1194-W, VN1194-P and 1194-LP viruses in mouse lung, blood and brain. Mice were infected i.n. with 100 pfu (A), or i.v. with 50 pfu (B) of each virus. On days three and six p.i., three mice in each group were sacrificed and virus titers in each organs or tissues were determined by TCID₅₀ on MDCK cells. The ratio of positive to total sample was labeled on the top of each histogram. A: Virus titers in the lung of mice infected with VN1194-W were significantly lower on three p.i. but significantly higher on six p.i. than those in the lung of mice infected with the other two viruses (P < 0.01). The differences of virus titers in mouse brain on daythree or six p.i. between the mice infected with 1194-LP and those infected with the other two viruses were also significant (P < 0.01). B: virus titers in the lung of mice infected with VN1194-W were significantly higher on both day three and six p.i. than those in the lung of mice infected with the other two viruses (P < 0.01), and the differences of virus titers in mouse brain on day three or six p.i. between the mice infected with 1194-LP and those infected with the other two viruses were also significant (P < 0.01).