Reality sets in today as the fields are empty and polo takes an involuntary break. The only news to report is that one horse in the quarantined Forum field stabling had a mild fever, though it exhibited no other signs of illness. We have established an isolation barn at the old showgrounds along Avenue 52. It provides the perfect set up far away from our horses and gives up plenty of separation among the many stalls available there should we need them. Since this horse comes from the initial outbreak zone, it has been moved to isolation as a precaution and was tested for EHV-1. Results should hopefully come back by Saturday. Access to and from this isolation is restricted so if you have a sick horse that you feel needs to be moved there please contact your veterinarian first and them have them contact me personally.
Many questions arise about preventative measures for other horses. As we have said, there is no specific vaccination for this neurologic strain of the virus. Boostering with the respiratory or pregnant mare Rhinopneumonitis vaccines does not afford any protection. In fact, the stress of vaccination on the immune system may be unwanted. Another product called Zylexis has been used as an immune stimulant and is given in a 3 shot series on days 1. 2 and 9. The company’s material itself only claims boosting response to the respiratory forms of EHV-1 and EHV-4, so its effects in protecting against the neurologic strain are again questionable.
In the case of a new infection, Valtrex or valcyclovir has been used in human herpes infections and has shown some benefit in the equine infection in certain cases. This is a 21 day treatment and can cost as much as $200 per day or more.
More than anything else, twice daily monitoring of temperatures is our most important key to assessing our horses. Again, we are not recommending random testing of horses that do not display fevers or clinical signs of the disease as the results cannot be accurately processed. False positives in healthy animals may only muddy the water and lead to undue concern.
Michael Manno, DVM, MS