UPDATE – May 24
The CDFA has posted current cases by county and status of those horses on their website http://www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html.
UPDATE – May 21
As of Saturday, May 21, 10 horses in California have been confirmed, two in Colorado, one each in Washington and Alberta. In Colorado there are also six horses that have shown the symptoms of the virus.
EHV-1 is most commonly spread by direct horse-to-horse contact, but can also be carried on contaminated tack and clothing.
It is believed that horses that are current on their vaccination are likely protected as flu-rhino includes EHV.
I am providing this letter of guidance, from Colorado State, for horse owners whose horses may have been exposed to horses with EHV-1.