Update provided by Dr. Scott Austin, DVM, Diplomate ACVIM, Wisconsin Equine Clinic
Since the last posting, the affected farm has remained under voluntary quarantine, and twice daily monitoring of temperature has continued.
There have not been any horses with respiratory signs, neurological signs, or fever since January 27,2007. Nasal swabs and blood were evaluated by PCR from all horses that have been febrile, tested positive for EHV-1, or been in-contact with any confirmed or suspected EHV-1 cases on on February 15, 2007.
All nasal swabs and blood tests taken on February 15, 2007 were negative for EHV-1. Since it has been 24 days since the last clinical signs and all in-contact horses have tested negative for the virus, it has been recommended that the voluntary quarantine be lifted.
The outbreak was confined to the 4 horses previously reported. The updated outcome of the 4 confirmed or suspected horses is as follows:
- Horse A: PCR positive for EHV-1 on nasal swab and blood. This horse developed neurological signs and was euthanized. Viral isolation confirmed that this case was neurotropic EHV-1.
- Horse B: This horse was febrile at the time of testing and had a positive PCR for EHV-1 on blood. This horse did not develop any clinical signs of disease and tested negative for the virus on both nasal and blood PCR's on February 15, 2007.
- Horse C: This horse was negative for EHV-1 on nasal swabs and blood but developed typical neurological signs of ataxia and bladder paralysis that progressed to rear limb paralysis. This horse was euthanised. A post-mortem examination has not been able to confirm the cause of the neurological signs at this time.
- Horse D: This horse was febrile at the time of testing and was negative for
EHV-1 on both blood and nasal swab. The fever resoloved within 36 hours and no clinical signs of respiratory or neurological disease have been seen. Repeat testing of nasal swabs and blood on February 15, 2007 were still negative for the virus.
Please contact your veterinarian with any questions you may have.
There are precautionary practices that horse owners and stable managers can take to help prevent the spread of any contagious disease. Those recommended practices are:
- Isolate new arrivals, sick horses, and horses returning from competition for at least 7 days. If you know that horses at the competition had confirmed EHV-1 infection, isolate your horses for at least 21 days before reintroducing them into your barn.
- Disinfect all areas of the barn in which a suspect horse has been housed or worked. Use bleach (1 part bleach to 10 parts water) or phenolic based disinfectants if significant organic material is around.
- Encourage barn personnel and riders to wear leather or rubber boot/shoes that can be disinfected. Use a disinfectant tub at the entrance to the barn and ask all visitors to step in it before entering and leaving. This includes blacksmiths and veterinarians. Change the bleach in the tub daily.
- Wash hands before handling horses.
- Do not share water buckets, feed tubs, or stalls among horses.
- Segregate horses into the smallest possible groups. Large groups of horses sharing a common airspace may all be infected by one or a few horses shedding the virus.
- Take rectal temperatures daily. Isolate any horse with a fever, over 101F for adult horses. Consult your veterinarian immediately.
