Infectious Disease Update – May 2017

There has been a number of reports of significant infectious disease in our area. Here is a quick summary:

EIA – Equine Infectious Anemia is a virus spread by biting insects. It can result in a very serious, and untreatable disease. When you have a Coggins’ test performed on your horse, this is the disease you are ruling out. A 5-year old racing Quarter Horse was diagnosed positive in Fort Lupton and was euthanized May 8, 2017. Since this occurred before many of the biting insects were around in large numbers, the hope is that no other horses will be affected. The barn is under quarantine for 60 days and all horses will be retested at the end of that time.

Strangles – This is a respiratory disease caused by the bacteria Streptococcus equi subspecies equi. This strep bacteria usually causes symptoms such as nasal and ocular discharge, coughing, fever and swollen lymph nodes that can rupture and drain pus. In severe cases, these lymph nodes swell to the point that they obstruct the airflow through the trachea, causing respiratory distress and even death. Rarely, it can also cause other symptoms such as colic, depending on whether the bacteria makes it to the abdomen. While we may see a couple of cases each year, this year has seen a higher than normal spread of the disease, including an outbreak at the Jefferson County Fairgrounds, home of the Westernaires Equestrian Team.

Rabies – This is a nearly 100% fatal virus that can easily spread between animals and from animals to humans. Two skunks and one fox were recently found to be positive for this disease. No horses or humans have been affected at this time. The signs associated with this disease are neurological (loss of coordination, odd behavior, sometimes aggressiveness) Another common sign is the appearance during the daytime of nocturnal animals or animals that usually hide. This disease can be prevented through routine rabies vaccination. If your horse has not been vaccinated against rabies within the last year, please call us to schedule one.

PPID Basics

PPID (Equine Pituitary Pars Intermedia Dysfunction) is a disease of the horse’s brain.  It is caused by damage to the nerves that control secretion of hormones by the pituitary gland.  Pituitary hormones include regulation for Cortisone, Thyroid Hormone, Hair growth, Urination, Lactation, and Reproduction.  Loss of control usually causes elevation of the various hormones, although sometimes it just mean loss of the normal up and down cycles that occur daily.

The signs of PPID are related to which hormones have gone out of control.  The most commonly observed ones are ACTH, which regulates body cortisone levels, MTH, which regulates hair growth, and ADH, which regulates production of urine.  As you might expect, the horse shows these problems by urinating too much, growing too much hair, or getting a large abdomen or foundering.  Horses that show the typical long dreadlock type hair are obvious.  The urination and reproductive issues must be tested for , indirectly, by looking at kidney, urine, and reproductive hormone levels.  Cortisol is best evaluated indirectly by measuring ACTH levels, although there are older tests such as the dex suppression test that can also be used.  Detecting cortisol elevations is vital because of the increase in insulin resistance it causes, as well as the direct suppression of the immune system and liver damage.

Once diagnosed, the treatment of PPID is medical, and the goal is to return hormone levels to normal.  Fortunately, we now have available a prescription medication to treat the disease called Prascend.  Prior to the availability of Prascend, we were forced to use compounded pergolide, which was shown in multiple studies to be very unreliable and unstable.  Prascend causes ACTH to go down to normal levels when dosed correctly in over 90% of the horses.  It is important to monitor the ACTH level at least twice yearly to be sure the ACTH is staying in the normal range.  There is a fall rise in the normal level of ACTH in August through December, and it is exaggerated in PPID patients.  This elevation causes an increase in insulin resistance, and is responsible for the fall laminitis episodes that occur each year.

Equine Metabolic Syndrome Basics

Equine Metabolic Syndrome (EMS) is a disease similar to Type 2 Diabetes in humans. Normally, when horses eat a meal, they absorb sugars from their intestines, causing an increase in blood sugar levels. In response, the pancreas secretes insulin, a hormone that helps glucose get into the cells where it can be used for energy. The circulating blood sugar thus goes back to a lower level. This is an active balancing mechanism.

In the EMS patient, the body becomes much less sensitive to insulin, and ever increasing amounts are required to return the blood sugar to normal. This lack of sensitivity to insulin causes a number of problems. First and foremost, there is significant evidence that chronically elevated insulin levels directly damage the lamina in the feet, causing founder. In addition, there is strong evidence of immune system damage, and increased fat deposition both externally (the crest, loin, and tail head), and internally, particularly in the liver. The internal fat is particularly damaging, because it releases various other compounds that amplify the insulin resistance.

Management of EMS in the horse is centered on dietary changes and increased exercise. Exercise is the best insulin sensitizer available. Riding 4-5 days a week for an hour is great therapy for both horse and owner. Each session should work up a sweat.

Modification of the diet to limit intake of soluble sugars is very helpful. There are broadly two types of sugars available in the horse’s diet. These sugars are classed as soluble and insoluble. Soluble sugars are things like glucose and fructose and taste sweet. Insoluble sugars are more like pasta. It is possible to measure the soluble sugars in hay and grain samples. The goal is to have less than 10% soluble sugars in the horse’s diet. Hays with more than 10% soluble sugars can be soaked for 30 minutes to remove the soluble sugars. Remember to pour out the water before you feed the hay! There are sources of low soluble sugar hay pellets and pre-formulated rations available from Purina, Nutrena, and others.

The other essential part of dietary management is total caloric intake. EMS horses need to be a little on the thin side. Normal recommendation for total caloric consumption is 1.5 pounds of feed (total hay and grain) per day per hundred pounds. If your horse is over weight, a weight loss program should be devised to get his weight down.  Remember, less fat = less insulin resistance.

Wound Care

My horse has a cut on his leg, what should I do?

This is one of the most common questions we hear. The critical things to know are depth, discharge, and whether important structures are involved. Wound depth can not always be determined by looking. In a typical wound, you can see hair missing, a raw spot, and maybe edges and deeper structures. If all you see is missing hair, the wound is not serious, and all that is required is to keep it clean with water. If you are able to identify complete edges on both sides of a wound, the wound is termed <em>full thickness</em>. Full thickness means that the skin has been cut clear through, and that structures inside are exposed to the outside. These wounds require inspection by your veterinarian, because they often are like an iceberg, bigger on the inside than on the outside. There may be tendons, ligaments, muscles or joints underneath that are damaged, and often there is debris like manure and hair packed inside. These wounds are likely to get infected and need medical management in order to get good healing. The last bit of information to process is whether or not important internal structures are involved. Wounds that involve joints, tendon sheaths, tendons, ligaments, or bone are particularly serious because infection or injury to these structures can become life threatening. These wounds can often be managed successfully if diagnosed early. Once infection has set in, it is much more difficult to achieve a good outcome.

A similar question is whether or not a wound needs stitches. Wound suturing is recommended for larger wounds, wounds with a lot of injury underneath the skin, if tendons, muscles, or joints are involved, and if a good cosmetic result is desired. Usually, sutured wounds heal faster than those left to heal by themselves, with less scarring.Wounds over joints can be successfully sutured, they just require specialized bandaging to limit movement while the cut heals.

My horse’s wound has pus coming out of it. What should I do

These wounds are infected, usually with bacteria and debris from the skin, as well as the barnyard. Infected wounds are swollen, red, have discharge, may or may not smell bad, and are painful. These wounds are treated in two ways. First, it is essential to decontaminate the wound. This is done by applying large quantities of hypertonic saline solution to the wound to dilute the discharge. The recipe for the solution is below. In a pinch, you can use a garden hose to decontaminate a wound. Do not apply Furacin, disinfectants, antibiotics, soap, bleach, Vetricyn, or other substances unless directed to do so by your veterinarian. Sampling of the wound for bacterial culture and determination of antibiotic sensitivity may be very important in order to get the infection resolved. Bandaging of draining wounds is helpful to remove discharge and protect the raw surfaces from recontamination by the environment.

Pain management for wounds is very important. Numerous studies have shown that adequate pain management speeds and improves the quality of wound healing. Minor wound pain is often well managed with anti-inflammatories like phenylbutazone, Previcox, or others. More substantial wounds may require opiates, local anesthetics, epidural, or other modalities to adequately control the pain.

Welcome to the NEW Cherry Creek Equine Website

Please excuse our dust!

The construction continues around here, but we are proud to finally launch our new website. With all of the crazy changes around here recently — new doctor, new technician, new location, new shoulder! — we thought we needed a facelift too!

On a serious note, we are very thankful that you are visiting us! As we redesigned this site we tried to keep our clients foremost in our decision making. Most horse owners have come to realize, there is a LOT of information and advice online. However, judging the good from the bad has become increasingly difficult. We know that many people are seeing all sorts of things online because we often get asked about things people have read or heard about from a friend.

For these reasons, we are excited to build this repository of curated information and recommendations so that you have a trusted resource. Our practice has always strived to advocate horsemanship, basic veterinary education and animal husbandry. Please check back regularly as new information is being added often!