How fast does West Nile kill a crow?

We have a sick crow, first noticed around 7:30 a.m. to the present, around 4:00 p.m.
I put some cat pellets out for it and it took one over to the pond and dropped in a shallow area to soak, but it did not attempt to retrieve it. The poor thing is very lethargic and is letting me get much too close to it for it to be healthy. It does not seem able, or even be trying to fly.
The health department said that there are too many to test and that I should just call animal control to come and get it. My feeling is that if it is going to die that it should be left alone in it’s last moments. So how long is this going to take? I thought that this virus (if indeed it is the WNV) would have taken it ong ago. I think it may be one of the three babies from this year’s nest and this is breaking my heart.
Any advice out there?

I don’t know, but there was 2 dead crows in our park in the past week. Scary.

I had a thread called “West Nile virus; hazard to predators?” (or something like that,) a chap whose job it was to test dead birds and know these things, said that the birds die in about a day. The victim birds were mostly corvids. That is, they were crows, blue jays, and, um, some birds I can’t recall. To be infected, one would have to either be bitten by a mosquito who had bitten an infected creature, or eat the creature itself.

WNV fever is nasty stuff. The encephalitis form can leave the victim rather badly dead. If you’d like to avoid that fate, wear insect repellant (DEET) , long sleeves and long pants.