Contagious Equine Metritis (CEM)
Filed under: Bacterial Disease, CEM, Reproduction, Stallion
Tawna Purcell, DVM
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Contagious Equine Metritis (CEM) has been a recent topic of concern for many veterinarians and some owners as of late. CEM, caused by the bacteria Taylorella equigenitalis, was first discovered in England in 1977 and was first identified in the United States in 1978 (in Columbia, MO). The disease was eradicated at that time until it made a brief showing again in 2006 and once again in 2008. Efforts to eradicate the 2008 outbreak are still ongoing.
CEM is highly contagious. Horses are often asymptomatic (no outward sign of infection) although some affected mares can show a mucoid vaginal discharge.
Transmission can occur through direct breeding, artificial insemination of a mare from an infected stallion or contact with items contaminated with the bacteria. Infection results in infertility or abortion in mares, while stallions have no clinical signs. Infertility can last for one or more breeding cycles and certain mares can carry the infection, potentially spreading it to others for many months.
Since the 2008 outbreak was first identified in Kentucky, a number of stallions and a few mares have tested positive for CEM, however some 991 horses, spread over 48 states, have been identified as potentially exposed to the bacteria that causes CEM. Most of these horses have now been tested as negative and the few found positive have undergone, or are in the process of treatment.
Testing of CEM is done in partnership between local and state veterinarians to insure proper methods and future eradication. There are three diagnostic methods available, the most common being bacterial culture in both stallions and mares. Should a mare test positive for the bacteria, a blood test will be done to detect systemic antibodies. Stallions do not develop these antibodies. Stallions who have tested positive, or who have been on a farm with a positive stallion will often undergo a test breeding to negative mares to insure he does not infect them with the bacteria. The process takes 35 days to declare the stallion negative. On average the process to clear a horse takes 6-8 weeks between tests and re-tests.
Although it may seem cumbersome, both mares and stallions can be diagnosed and successfully treated with topical and systemic antibiotics. That along with good hygiene practices will help eradicate CEM from the US once again.
Eye Injuries
Filed under: Corneal ulcer, Emergency, Eye Problems, Laceration, Uveitis
Hunter Ortis, DVM
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The most frequent eye related problems in horses are corneal ulcers (abrasions to the surface of the eye), eyelid lacerations and uveitis. Clinical signs of an eye emergency include excessive tearing or discharge, spasmodic squinting, holding the eye partially or completely closed, or constriction of the pupil. Additionally, changes in appearance of the eye and its surrounding structures such as swelling of the eyelids, increased redness of the usually pink tissue around the eye, and cloudiness of the cornea are signs of an eye problem.
The most common injury of the eye is a corneal ulcer. Ulcers occur when the surface of the eye comes in contact with a foreign object such a hay stem, stick or surface of a stall wall, leaving a defect in the integrity of the surface of the eye. A horse with a corneal ulcer will usually have symptoms of a painful eye and/or a hazy bluish appearance of the surface of the eye. Corneal ulcers are diagnosed with a fluorescing stain applied directly to the cornea during examination. Treatment usually includes topical antibiotics because the cornea is easily infected. Other medications may be indicated on a case by case basis.
Eyelid lacerations are commonly caused when the eyelid simply gets snagged on a piece of stall hardware, an overlooked raised nail or piece of wire. These injuries are much easier to diagnose than most other eye emergencies but are equally important to seek rapid veterinary attention. Most lacerations involving the margin of the eyelid will require repair with suture. The integrity of the eyelid margins is vital for maintaining a proper tear film on the surface of the eye. An irregular eyelid margin can cause recurring and chronic eye irritation.
Uveitis, or inflammation in the interior portion of the eye, occurs when inflammatory mediators are released causing leakage of damaging proteins into the internal structures of the eye. There are many different causes of uveitis including blunt or penetrating trauma, corneal ulcers, systemic diseases, and unknown causes to name a few. Most horses with uveitis will show signs of a painful eye that appears cloudy. Diagnosis is usually made with findings from a complete eye examination including the use of an ophthalmoscope. Rapid and aggressive treatment, often with multiple topical and systemic medications, is essential in minimizing the possibility of permanent damage to the internal structures of the eye.
Injuries of the equine eye should be considered an emergency, and owners should consult their veterinarian immediately when a potential problem has been identified. Delaying treatment or instituting improper treatment on some ocular conditions can lead to permanent damage to the eye and loss of vision.