There are 9 states with fewer square miles than San Bernardino county, including all the New England states.
I grew up in San Diego, and had relatives in Riverside county, so we were up there a lot. Now I’m in Massachusetts. The whole New England/East Coast thing of being able to travel through 6 or 7 states in one day was really weird to me at first.
Not saying it’s in Brea. Just that Brea is contiguous to San Bernardino county. Have no idea where VS is in the OC.
Indeed, I heard through the grapevine that Silverado Canyon had some cases.
ETA: I had the wrong canyon
Rumor is it is in Trabuco Canyon, which is contiguous with Coto de Casa and Rancho Santa Margarita.
There are conflicting reports now. I will wait to update until we know for sure. It is in one of the canyon communities in eastern Orange County against the base of the mountains, the other side of which is Riverside county.
Unsurprising. It will be all over Southern California by the end of the summer, in my opinion. Flies are tricky and can hitch rides in all sorts of places.
Agree. The 2020 Arizona outbreak lasted 6 months from start to finish, and spread to 4-5 states.
We’re now three weeks from the initial alert/confirmed case (May 17), and I know a few barns in San Diego are just now getting the word out to clients and boarders about protecting horses. 
Now in Los Angeles.
But, as is the case with Orange County, we don’t know which city. Though neither of those counties is as large as San Bernardino County.
And, unlike the EVH reports, there’s no info on whether the affected animals had been at a competition recently or any demographic info on the horses.
A rhinoceros is San Diego county has it, presumably at the Safari Park.
USDA Link - requires additional navigation
It is not in Santiago Canyon.
The quarantined facility in eastern Orange County is in Modjeska Canyon, off Santiago Canyon Road. There is another rumored suspect facility in Trabuco Canyon.
A rhinoceros at the San Diego Wild Animal Park has vesicular stomatitis now. Flies fly where they will. Poor rhino!
Really weird virus. Seems to be very hit and miss. Large facility in south Riverside had only a few horses out of hundreds. Backyard mom and pop’s seem to have one or two get it but not others. No big spreads reported from shows/events. The ones that have gotten it have been stay at home variety. Horses are only infectious if oozing vesicles present, so it would seem fairly simple to just stay away from the ones with “cooties”. The flies and their friends are the culprit. Too bad they can’t dispatch pesticide spraying drones… 
It’s spread by flies? How does that stop it from spreading to neighboring states unless they shut down horses being trailered out of state? Flies can ride along quite comfortably in trailers, especially the fancy enclosed ones people tend to have now. I would worry if I had horses in neighboring states.
How deadly is it?
Does it die off with the flies during a good freeze? How can SoCal get rid of it if it doesn’t get cold enough?
It’s not deadly. From the USEF alert:
“VS is a viral disease of horses and other animals. Infection results in vesicles (blisters), crusts, and ulceration of the lips, muzzle, nose, tongue, ears, sheath, teats, and/or coronary band. Transmission is predominantly by black flies, sand flies, and biting midges. The virus is in the active lesion, thus animals with active lesions can transmit the virus by direct contact, shared feed/water sources, and other carriers contaminated by infective lesions, vesicular fluid and/or saliva. The lesions are self-limiting and typically resolve within 14 days. Humans can be infected from exposure to this virus and have mild flu-like symptoms.“
There’s a suspected case at Middleranch main ranch, which is on lockdown (no horses in or out.). So that’s the edge of the San Fernando Valley.
While our flies may not die off completely, there are far fewer in the winter. They ramp
up as it gets hotter. One thing that may be helping at the moment is that May Gray and June Gloom have been gloomier, grayer, and more persistent than usual, resulting in cooler temperatures, even inland. On the other hand, September and even into October can be pretty warm, meaning that VS could stick around well into fall. This was noted in the email that USEF sent out yesterday.
Thank you! If it isn’t deadly, why is it causing such a panic? A self limiting virus that resolves within 14 days is certainly better than other human and equine illnesses we face. Is it that it’s interrupting show schedules?
Two things make it a big deal to CDFA and the equivalent entities in other states. It has an impact on commercial agriculture (cattle) and it presents similarly to hoof and mouth disease. IMHO if it weren’t for one or both of those it wouldn’t even be a reportable disease.
CDFA VS Factsheet - https://www.cdfa.ca.gov/ahfss/animal_health/pdfs/VS_Factsheet.pdf
Aaaaaah, that makes perfect sense now. I have never seen it or been in a state that had an outbreak. Good learning experience. It could be my state next.
Because some like to panic, lol! It’s also proving not to be as infectious (horse to horse) as some are making it out to be. When you have a facility with 400+ horses and only a few get it, what does that tell you? Some events were cancelled early on, then we saw that a BIG h/j show could be held right next to the quarantined facility and nothing happened. Hmmmmm.
It’s highly contagious, and people can get it from an infected horse. The USDA vet that presented the USEF/USDA webinar about it said that she caught it from an infected horse when the horse sneezed in her face. She was very ill (like a bad flu, aches and pains, fever) for about 3 days.
Also people are concerned about it because it’s painful to the horses ! They can stop eating, and drinking because of the sores in their mouth and lips. Several infected horses in San Diego are on IV’s to keep them hydrated.
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