Thursday, March 12, 2009

Equine Infection Anemia and the Coggins Test

At the end of March I am going to have my friend, Max, ride the newest addition to our herd, Bailey the pony, for a month to get her in shape for spring. She'll also be evaluating the pony's disposition and abilities as they relate to being ridden by a young child - namely, my granddaughter. Ponies are great for young kids, but I still want to have Bailey ridden by an experienced rider first.

In preparation for this, I had the veterinarian out the other day to draw blood for a Coggins test, which is required for any new horse coming into Benvelle Equestrian Center.

I can remember a time when this test was not required, in fact I hadn’t even heard of it when I first started with my horses. The Coggins test, which is now widely known, is to prevent the spread of EIA (equine infectious anemia) by detecting those horses that are positive and/or carriers of the disease.

EIA, also known as Swamp Fever, is a retroviral infection which persists for the life of the horse and for which there is no vaccine, no cure, and no effective treatment. It is related to bovine and feline leukemia and HIV. In simplified layman’s terms, a retrovirus is a deadly virus that changes the nucleus of the body’s cells which can cause malignancies and EIA or HIV.

EIA, similarly to HIV, is transmitted through bodily fluids, but mainly through biting insects, especially horse and deer flies, with the large horsefly as the main carrier. The virus doesn’t live long in the fly so horses must be within close proximity in order for the fly to transmit the disease. It can also be transmitted by re-using needles, and has in some instances been transferred from a mare to her foal.

There are 3 forms of Equine Infection Anemia disease:

  • Acute: the horse develops fever, depression and goes off his feed 1 -4 weeks after infection. He may appear to recover, but is developing anemia.
  • Chronic: the horse has developed anemia which can come and go. He appears to have recovered, but it recurs, especially during times of stress.
  • Carrier: the horse is infected, but shows no signs of the disease. The longer it goes undetected, the more other horses can be infected.

If a horse is tested positive for EIA through the use of the Coggins test, it must be either destroyed or isolated for life. All potentially exposed horses must then be tested. A few years ago a horse at Benvelle tested positive. The mare, who had a foal at her side, was put down and the whole barn was quarantined until 2 separate tests, performed 45 days apart, came back as negative for each horse. I also remember another time, quite a number of years ago, when someone up in the Brainerd area brought a new horse into the herd that was discovered to have EIA and it ended up that half of the horses on that farm either died or had to be put down.

It is now a requirement of all shows and sales that a horse have proof of a negative Coggins test. The cost of approximately $20.oo per test is a small price to pay for peace of mind and also, hopefully, the eventual eradication of the disease.

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