This is from a seminar on West Nile last week at Kansas State University.

The horse information was given by Dr. Bonnie Rush, Clinical Sciences, KSU
College of Veterinary Medicine. Just thought I would pass on some of the more
pertinent and interesting information she presented. Feel free to cut
and paste this email to any other forums or sites you wish.

Refresh water containers 1 time per week. If you have large stock tanks put
in goldfish or minnows to eat the mosquito larvae.

Light colored horses seem more susceptible and come down with the disease
more frequently than dark colored horses. A horse in the evening in a wooded
pastures gets approx 2000 mosquito bites per hour. If unvaccinated, they are
25 times more likely to get the disease and 8 times more likely to die if
they get the disease than vaccinated horses. Approx 27% of the horses get
protective antibodies without showing any signs.

Old age and stress (i.e. stallions) increase the occurrence. Vaccinate 2
times per year after initial first time booster, so give in early spring and
around July. Foals from vaccinated mares should be vaccinated at 3,4, and 6
months. Foals from unvaccinated mares should be vaccinated at 1,2,3, and 6
months.

Cost for average recovery if they get sick - $1100-$1400. Cost if they go
recumbent....$2500 and 70% of the ones that go recumbent will die from it.

They saw no correlation between the vaccine and abortion or still birth but
said an unvaccinated mare that contracted it was much more likely to lose her
foal.

Of the 55 cases that KSU saw this year, 5 were vaccinated
and all 5 lived that were vaccinated lived.