Equine Warts

Although unsightly, warts are generally a trivial disease, provided the horse is given good nutrition and care. Papilloma virus is the cause of warts. It is a virus and is contagious to other horses, but not to humans. It is interesting to note that this virus can be carried by biting insects carrying the virus. If a horse has warts he should be kept away from other horses. Also, do not use any tack from the infected horse on any other horse. Good stable management is really important. Good nutrition and a worming schedule are tantamount.

Warts usually appear on the face, mouth, or nose. Because younger horses have a less efficient immune system they are more susceptible to warts than older horses.    Warts can be single in appearance or they can cluster. Sometimes they look like a cauliflower head. Time will usually take care of warts. Most will disappear within 6 to 9 months, if left alone, because the infection is self limiting. As the younger horse develops a more efficient immune system he will build up immunity to the virus.

Complications from warts do not usually occur. If they do usually they are secondary. For example, injury caused by scrapes or bangs on barn doors, fencing or tack that rubs can cause sores which get infected. If a wart is rubbed raw "summer sores" can occur on the warts. Maggots or other insect larvae can be laid on wart in these open wounds. In the heat of summer extra care must be taken if your horse has warts. Increased insect and horse activity give greater rise to secondary infections.

Other than secondary infections there are no real health consequences associated with warts. The only time warts become dangerous is when a horse has an immune deficiency such as CID* which compromises the immune system. In these cases, the warts could become much more extensive and cover wider areas of the body because the animal's immune system will not contribute to self-curing. The warts can persist and all sorts of health problems can occur as a result.

Sometimes surgical removal of warts is recommended. There is some thought that if warts are numerous, surgical removal may stimulate the immune system to clear up the virus more quickly. This has not been definitively proven because warts are self curing in horses. Talking to your vet is always advised.

*CID is equine combined immunodeficiency disease. It is caused by homozygosity for an autosomal recessive gene. There are markers that have been linked to CID and are used to identify horses that have this gene.