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[RC] OutBreak 2. - Steven Proe

From:
Bayhill Equine
Dr. Wayne Browning
123   Belmont Avenue
Redwood City   , CA      94061  
(650) 851-2300 ? BayhillEq@xxxxxxx 
 
As most of you already know there has been a recent outbreak of the neurotropic form of Equine Herpes Virus (EHV-1) in Montara.  This was the first confirmed case in San Mateo     County    . To date, Bayhill Equine is the only veterinary practice that has seen, or treated any horse involved in this outbreak.Therefore, as many questions have arisen, I felt I should respond to a previous post to let people know the current status and avoid any misinformation.     
 
I originally saw a 4-year old filly on Monday morning, March11, that was unable to stand and had a history of fever 5 days earlier.  Another horse in the same paddock was also showing signs of ataxia (incoordination).  Based on clinical signs, history, and multiple horses affected, a tentative diagnosis of EHV-1 was made and the horses referred to UC-Davis.  By 5:15     that afternoon, a positive diagnosis was confirmed by laboratory tests.  I called at area veterinarians on Tuesday morning, which is where they got their information.  Both horses were started on Valcyclovir, but were euthanized yesterday after failing to respond to treatment.    
 
Two other horses on this ranch were febrile and were thus tested.  One was positive and one was negative.  Of of these horses had gone on a ride with members of a neighboring ranch one day prior to breaking with a fever.  Additionally, a 29 year-old mare was euthanized on a second neighboring ranch after being unable to stand.  She and one additional horse tested positive today, March 15th. Therefore, these three ranches are currently on a voluntary quarantine based on recommendations from out practice and those of UC-Davis.    
       
No new horse had been introduced on the primary ranch for 6 weeks, and the last horse to do so was from Pescadero.  Dr. Magdesian at UC-Davis felt that a fomite, such as clothing or shoes, could have been the introduction method.  He did not believe it was a spontaneous mutation. Additionally, Drs. Madigan and Dr. Ferraro are planning a site visit after obtain ranch owner approval both to study and to make further recommendations to contain the outbreak.      

I have attached a copy of the letter I wrote today, which is an updated version of the one posted on the 12th.  Also, we have additional pages covering prevention, treatment, and management that are available.  You may contact our office for these or with any addtional questions regarding the status of this outbreak.  
 
PS.
 
1) Obviously contact your regular veterinarian for information regarding treatment, prevention, etc.  I simply said that we have those papers already available which include links to appropriate web sites for the latest information, etc.

2) Bayhill Equine is working with UC-Davis to contact the ranch owners to obtain permission to visit the properties. We will be there as well to ask questions of them, etc.      
 
3) We are holding a community forum for all boarders on the coast so we can update them with the latest information as well in hopes of limiting this outbreak.