Volume 10, Number 12—December 2004
Research
Differential Virulence of West Nile Strains for American Crows
Figure 3

Figure 3. Survivorship of American Crows previously immunized with West Nile virus (WNV)-KUN or WNV-KEN viruses after injection with 1,500 PFU of NY99 WNV. hd, high dose.