Diseases

Name: Azoturia (Tying-up, Monday Morning Sickness)

Cause: The horse has been at rest for a few days but has been receiving his normal work ration during the rest period and is then returned to hard work. Signs develop upon return to work.

Main Parts Affected: Muscles and kidneys.

Symptoms: Most notably paralysis of muscles of the back, loin, croup, and hind quarters. Horse staggers and falls if not pulled up, and if he falls he attempts to get up, but his hind limbs remain stiff. Muscles involved are hard, hot, and trembling. Also, labored breathing, sweating, and urine is reddish brown.

Detection: See Symptoms

Treatment: Call the vet, stop the horse and keep him from moving, if he can't stand up, change his recumbant position ofter, massage the affected muscles, apply warm applications the the affected muscles.

Prevention/Precaution: Reduce ration when animal is not being worked and make sure the ration has adequate vitamin E and selenium.

Notes: Tying-up is the mild form. Azoturia causes destruction and scarring af affected muscles and causes kidney damage. When a horse has had one attack it is more susceptible to another.

Name: Colic (abdominal pain)

Cause: Mismanagement: not feeding regularly, long fasts followed by a full ration, full ration followed by hard work, feeding on the ground (dirt and sand accumulate in stomach and intestines, this form termed 'sand colic'), abrupt changes in grain ration, insufficient water supply (causing and 'impaction'), giving large quantities of water to a hot horse, gas, and a partial or complete obstruction of worms in digestive tract (worms also damage the intestinal tract and predispose a horse to colic). Also, twisted or displaced intestines or a ruptured stomach (these last are often fatal).

Main Parts Affected: Digestive system.

Symptoms: Mild colic: Abdomen distended by feed or gas, not interested in food, lying down on side, horse looks at his flank, kicking at flank, pawing the ground, frequent attempts to urinate, absence of normal gut sounds or abnormally loud sounds. Signs of severe pain: repeatedly lying down and rolling violently, sweating profusly in patches all over the body, rapid breathing, body language shows anxiety.

Detection: See Symptoms High temperature indicates the pain is serious, as well as a fast irregular pulse. A lot of pain indicates severe colic.

Treatment: For mild cases, calm the apprehensive horse, make sure he has a thick dry bed (banked high against the walls in case the horse decides to roll), take away all his feed (leave the water). If mild pain persists for more than 30 minutes or returns after a period of relief, or if there is acute pain, call the vet immediately. Don't walk the horse on and on endlessly because it might tire the horse. If the horse is dangerously violent don't hang around too closely, in its thrashing you may accidentally get hurt. Don't feed the horse until the day after recovery, and even then, only feed a small ration.

Prevention/Precaution: Effective routine worm control, regular feeding regimen and rations, including clean fresh water at all times (other than when the horse is hot from hard work) and feeding little, and often. When you must make a change in diet, do it slowly, add more of the new stuff and less of the other stuff gradually, it is essentially the same process when other routines (such as the amount or kind of exercise) are going to be changed. Have the teeth checked regularly.

Notes: As a rule, a colicky horse will not chew and swallow feed, though he may play with it. It is not a good idea to give liquid medicine to the horse because it may not swallow and it could go down the wrong way, into the lungs.

To learn more about colic:

Name: Equine Protozoal Myeloencephalitis (EPM)

Cause: EPM infects a horse when it ingests food or water which has been contaminated by the droppings of an infected opossum or bird (except for that of chickens and guinea fowl).

Main Parts Affected: Central nervous system.

Symptoms: Signs of neurological dysfunction (mild lethargy, relatively poor bodily condition, attitude change, reduced exercise tolerance). Also: incoordination, inability to stand up, lameness, blindness, inability to chew food/swallow, facial palsy, abnormal eye movements, stumbling and falling, seizures and convulsions, headshaking, muscle tremors, inappropriate patchy sweating, collapse, discrete loss of specific muscle groups (neurogenic atrophy). Keep in mind other diseases have some of the same symptoms; just because some symptoms appear does not necessarily mean the horse has EPM.

Detection: Spinal fluid western immunoblot test.

Treatment: Medication and rest/minimize stress. Treatment should be undertaken for at least 12 weeks plus a further 4 weeks after syptoms disappear.

Prevention/Precaution: Discourage wild birds from roosting or nesting in stables, special fencing/trapping to eliminate the opossum, and discourage opossum from hangin' around by eliminating food sources All grain should be stored in tightly closed containers, dog and cat food should not be left out, if dogs or cats must be fed in the barn, feed only the amount the animals can eat at one time. Other possible food sources for opossums include fruit trees, spoiled meat, and garbage, dead animals should be disposed of expeditiously and not allowed to rot. Food material should NOT be available to opossums in areas where horses are kept. Distance manure piles from the barn (opossum may look through manure looking for undigested grain and fly maggots).

Notes: The protozoan Sarcocystis neurona causes EPM. The immune system of a healthy horse can fend off the protozoa before any harm is done. The horse is a dead-end host (infected horses do not spread the disease); EPM is not contagious from a horse to another living being. Some horses fully recover, a significant number of horses eventually relapse and develop further active EPM.

To learn more about EPM:

Name: Equine Infectious Anemia (EIA, Swamp Fever)

Cause: Caused by a retrovirus similar to that of the HIV virus in humans. Horse flies who bite infected horses and then bite healthy horses spread EIA, as does anything else that moves blood from one horse to another in a short period of time. Virus present in the infected horse's blood, milk, semen, urine, feces, saliva, and in nasal and eye secretions. Contaminated hypodermic needles, dental floats, and surgical instruments. Of less importance are: contaminated bridle bits and feed or water, infected milk of broodmares, and infected semen of stallions.

Main Parts Affected: Immune syspems.

Symptoms: Symptoms vary from horse to horse and can mimic other diseases. Some individuals may demonstrate no obvious signs. Subacute form: less severe than in the acute form, death seldom occurs, apparent recovery followed by relapses, weakness, loss of weight, and anemia. Acute form: fever of 104-108 degrees F, weakness characterized by wobbly or rolling gait, depression, loss of appetite and over-all condition, swelling of lower body parts, yellowish or bloody nasal discharge, severe anemia weak, irregular heartbeat and/or weak pulse, death usually occurs. Chronic form: feve, lack of stamina, inability to perform hard work, anemia, may at any time revert to acute or subacute form.

Detection: Coggin's test (blood sample is taken and placed under the agar jel immuno-diffusion test [AGID] developed by Dr. Leroy Coggin's - hence 'Coggin's Test').

Treatment: Call vet. No vaccination. No cure. Euthanasia or permanent quarantine.

Prevention/Precaution: Prevention is the only way to keep your horse from contracting EIA. Only buy horses with a negative Coggin's Test report. Stable owners should require current negative Coggins certificates before introducing any new horses. Control biting insects. Eliminate contact of noninfected horses with the secretions, excretions, and blood of EIA infected horses. Remove manure and provide adequate drainage to discourage breeding sites for pests. Thoroughly disinfect any equipment to be used on more than one horse. Test all horses for EIA at least annually. Horse show and event managers should require and verify current negative Coggins certificates for all horses entering the premises, if they don't, don't take you're horse there. Negative Coggin's test is needed to board at a barn, to show or sell your horse, and whenever you transport your horse across state lines.

Notes: All positive cases must be filed with the state veterinarian and the federal Animal and Plant Health Inspection Service office. There are seasonal and reagional differences in EIA. Horses in certain states are more likely to get EIA, and because of insect populations horses are most likely to catch it in the summer and autumn months.

To learn more about EIA:

Name: Equine Recurrent Uveitis (Moon Blindness or Periodic Opthalmia)

Cause: invasion by bacteria of the genus leptospira, repeated eye infections caused by streptococci, parasites (ex: onchocerca, Toxoplasma gondii), trauma (blunt or intrusive), or possibly allergies.

Main Parts Affected: One or both eyes

Symptoms: Squinting half-closed eyes due to photophobia (sensitivity to sunshine), pupil constriction in the dark, watering eyes, redness (red blood vessels at the sides of the eye and in the lids), cloudiness in cornea, swelling, pus, head shaking, a runny nose, white spots or bleeding in the eye, loss of balance, tripping, running into things or rubbing the eye, stops grazing, decreased appetite, spookiness, blinking, grumpiness, and ulcers (may need to stain the eye to see them). Each attack causes more damage to the vital structures of the eye. Usually eventually leads to blindness.

Detection: Uveitis unfortunately is often misdiagnosed as something less severe or in some cases it is totally ignored. It is important that uveitis be diagnosed correctly because lack of or incorrect treatment can have serious consequences. Diagnosis may require tests such as: blood count, serum biochemical profile, urinalysis, leptospirosis, toxoplasmosis, and brucellosis titers, and fecal exam for parasites.

Treatment: Keep the horse in a dark stall during attacks. Treatment must be prescribed by a veterinarian because if a steroid is used when the eye is ulcerated, blindness can result. Vet may administer antibiotics and corticosteroids. If signs persist even with treatment, you or your veterinarian may want to consult a veterinary ophthalmologist, as this disease can lead to blindness in one or both eyes if not treated aggressively.

Prevention/Precaution: Some vets recommend the horse be vaccinated for leptospirosis. Control parasites and implement proper sanitaion measures.

Notes: Symptoms may ease and come back weeks or months later. That is why it is called Equine *Recurrent* Uveitis or *Periodic* Opthalmia. And *Moon* Blindness because it was once thought to have something to do with the *moon.*

To learn more about Moon Blindness:

Name: Heaves (Chronic Obstructive Pulmonary Disease [COPD], broken wind, emphysema)

Cause: A hypersensitive reaction to fungal spores in dusty hay or straw. Small air ways in the lungs (alveoli) are chronically obstructed.

Main Parts Affected: Lungs

Symptoms: (In order from first to worst) Nasal discharge (esp. during feeding or first thing in the morning), dry cough becoming more pronounced during exercise, decreased athletic performance, increased breathing rate due to a difficulty breathing.

Detection: Presence of symptoms.

Treatment: Avoid damaged, dusty, or moldy hay. Hay should not be given unless it has been tested for risk of fungal contamination or has been cured properly, otherwise hay could be substituted by pelleted feed, vacuum-packed cut grass, or silage. Dunking hay in water before feeding may help. The horse should not be bedded on straw, stall should be kept clean and dry (to prevent spores from accumulating there), stable should be dust-free (it should be in the first place), proper ventilation, shouldn't be down wind of the manure pile or hay or straw stacks. Certain drugs can help treat the condition. Sometimes keeping the horse at pasture helps, or at least keeping the horse out of doors as much as possible.

Prevention/Precaution: Stall kept clean and dry (to prevent spores from accumulating there), dust-free stable, proper ventilation, stabling shouldn't be down wind of the manure pile, hay, or straw stacks.

Notes: Permanent once a horse becomes hypersensitive to the spores. Good careful management can ward off the symptoms for a long time, but trouble can still occur when the horse is exposed to the spores. It is cumulative - the symptoms get worse and worse. Because of the difficulty in clearing their lungs of air before taking another breath, the use of abdominal muscles to assist in pushing air from the lungs results in those muscles becoming stronger and we see them as a sloping groove along the horse's abdomen. That is what is referred to as a "heave line". Once out of the early stages, horses diagnosed with heaves don't recover or ever become truly cured, but they can be managed successfully, although they can only be worked lightly.

To learn more about heaves:

Name: Influenza (Flu, Shipping Fever)

Cause: Two distinct strains of the influenza virus. Contact with infected horses (especially when large numbers of horses gather, like at shows and sales) and equipment. Certain conditions make the horse more susceptible: shipping, sever cold, sudden weather changes, and fatigue.

Main Parts Affected: Respiratory system

Symptoms: Inflammation of the nasal passages and throat, fever (sudden, rapid rise in temperature: 103-106 degrees F), dry and harsh coughing, wheezing/rapid breathing, lack of appetite and depression, muscular weakness, soreness, watery nasal discharge

Detection: See Symptoms

Treatment: Call vet, keep the animal quiet, warm, and out of drafts, provide adequate water. Don't return the animal to work too soon.

Prevention/Precaution: Vaccinate. Give booster 2 weeks before showing. Isolate infected animals, quarentine infected animals for 2-3 weeks, burn infected bedding, disinfect equipment and stalls.

Notes: This disease is most common in young animals. Secondary infections like pneumonia may be fatal. Heaves or bronchitis may develop after the flu.

To learn more about Influenza:

Name: Pneumonia

Cause: Virus, bacteria, or other organisms entering and cuasing inflammation of the lungs. Complication of another disease, like influenza. Improper drenching, allowing liquid to enter lungs instead of stomach. Worm larvae in lungs. Certain conditions predispose animals to pneumonia: chilling, fatique, malnutrition, damp, chilly barns, changeable weather.

Main Parts Affected: Respiratory system

Symptoms: Chill and a fever of 103-107 degrees F. Rapid pulse and respiration, difficulty breathing, and a moist cough.

Detection: See Symptoms

Treatment: Call vet. Keep animal warm, eliminate drafts, provide water and soft, laxitave feeds. The vet's early treatment of antibiotics and sulfa drugs is usually very effective

Prevention/Precaution: Administer oral medicines properly, control parasites, good sanitation, and proper care of animals with minor illnesses to prevent secondary infections.

Notes: Left untreated, the fatality rate is about 50-75%

Name: Potomac Horse Fever (PHF)

Cause: Ehrlichia risticii invading the horse's white blood cells. Freshwater snails and the larvae of flukes (parasitic flatworms) play key roles in Potomac horse fever's transmission.

Main Parts Affected: Digestive system

Symptoms: Depression, fever, lack of appetite, decreased gut sounds, abortion (placentitis and retained placenta are possible complications) in the mare, colitis (inflammation of the colon), distended abdomen, diarrhea (but not chronic diarrhea) which a complication being dehydration, then impaction colic, and then laminitis.

Detection: Making a quick and accurate scientific diagnosis can be problematic.

Treatment: Doses of oxytetracycline given intravenously by a lisenced veterinarian. Supportive therapy, such as intravenous fluids, electrolytes, or anti-inflammatory drugs may be necessay.

Prevention/Precaution: Keeping horses away from the streams, ponds, and other aquatic habitats in which snails and the larvae of flukes (parasitic flatworms) live. The vaccines (designed to produce circulating antibodies in the *bloodstream*) as of October 1998 aren't 100% effective because they aren't producing immunity at the site where the infection takes place (drinking water, eating an infected insect, etc). Not just that, there is widespread genetic diversity among Ehrlichia risticii bacteria, and the vaccines were not designed to offer immunity against all of the different strains.

Notes:

To learn more about PHF:

Name: Ringworm

Cause: Fungal infection (not a worm, and not exclusivly round) usually spread by contact with infected horses or their tack.

Main Parts Affected: Skin, commonest in places which might be rubbed by tack.

Symptoms: Small hairless patches of crusty skin. Skin is not inflamed and in general does not bother the horse.

Detection: Presence of symptoms

Treatment: Quarantine, skin wash, tack and all rough surfaces around the stable should be washed with the same wash or in a strong disinfectant which is effective against ringworm, and a certain drug should be given orally for a week.

Prevention/Precaution: Avoid contact with horses known to have ringworm. If your horse comes in contact with a horse who is found to have ringworm, skin wash horse and tack. If one of your horses has ringworm don't forget to quarentine the horse and its blankets, grooming tools and tack to prevent spreading.

Notes: Ringworm has a long incubation period, so a horse can be infectious even before anyone knows it has ringworm. Ringworm eventually cures itself. Humans can get ringworm from horses, and horses can get ringworm from people.

To learn more about Ringworm:

Name: Rhinopneumonitis (Equine herpesvirus, equine rhino, rhino, Equine Viral Rhinopneumonitis [EVR], Equine Viral Abortion [EVA])

Cause: Strains 1 and 4 of equine herpesvirus. Contagious. Direct contact with aborted fetus.

Main Parts Affected: Upper respiratory tract

Symptoms: In pregnant mares: may show no signs, abortion between 8th-11th month of pregnancy, delivery of a dead foal, delivery of a weak foal which will die within hours or days. Fever of 105-106 degrees F, off feed, moist cough, clear, then cloudy, then yellow nasal discharge, usually recovers in 1-2 weeks.

Detection: See symptoms

Treatment: None for pregnant mares. Call vet, isolate sick animals, vet usually administers antibiotics and cough medicine to young, infected horses.

Prevention/Precaution: Vaccinate. Isolate mares that have aborted, quarantine incoming horses, have aborted fetus examined in a laboratory.

Notes: When it happens in young animals, especially foals, results can be disastous. A mare that has aborted due to rhino can usually be bred again in the same season and produce a normal foal the next year.

Name: Strangles (Distemper)

Cause: Bacteria called Streptococcus equi. Direct contact with discharge from infected horses. Contaminated feed tubs, water troughts, equipment, handler's clothes, and bedding. May be transmitted through a wound (especially those around the face or through a castration wound).

Main Parts Affected: Upper respiratory tract.

Symptoms: Fever of 103-105 degrees F accompanied by mild depression, smelly and yellow discharge from the nose. Difficulty swollowing. Difficulty breathing, moist cough, and lost appetite. Glands near the angle of the jaw may be hot and swollen and can burst open, allowing the glands to drain. Following this, recovery is prompt.

Detection: See Symptoms

Treatment: Call vet immediately. Keep the horse at a low stress level, allow lots of rest, keep the horse warm and dry, provide clean drinking water and change it often to remove infected nasal discharge dripped in it by the horse. Hot compresses on abscessed lymph nodes will promote rupture and drainage. The vet will lance the swellings if necessary. When the abcesses have burst, antibiotics should kill the infection.

Prevention/Precaution: Strict hygiene to prevent the spread of bacteria. Vaccination yearly by injection or intranasal spray (the horse can still catch strangles, but it would be in a milder form, and the horse can still be contagious). Isolate infected animals. Quarantine new horses for at least 2-4 weeks. Thoroughly disinfect area and equipment after the horse recovers. When stabling horses away from home know about any recent strangles outbreaks at that the places you are being stabled. Notice whether any horses your horse might come in contact with has signs of infection.

Notes: Strangles is an contagious throat infection. There is an good chance of recovery if properly treated. One set of equipment for each horse reduces risk of contamination before there is an outbreak.

To learn more about Strangles:

Name: Tetanus (lockjaw)

Cause: A bacteria called Clostridium tetani, which release a toxin which attacks the nerves. They enter by way of wounds in the skin (especially by punctures, since they close over quickly, providing the anaerobic conditions the bacteria need to survive), or an abrasion of the intestinal wall.

Main Parts Affected: Nervous system

Symptoms: Stiff muscles, muscle spasms, pain, third eyelid may become exposed, over reacting to noise and sudden movements, the horse becomes unable to stand, difficulty eating and swallowing, stiff legs, partly elevated tail, head and neck stiff and stretched forward, temperature normal until the disease is far advanced, total paralysis.

Detection: A horse who exhibits the symptoms, especially those accompanied by the exposure of the third eyelid.

Treatment: Call vet immediately. Isolate animal in a dark, quiet stall. Provide water and laxitive feeds at head level. Antibiotics and tetanus antitoxin may be administered by the vet. The horse may need to be supported with a sling for a time if the leg muscles have been affected.

Prevention/Precaution: Yearly vaccination with tetanus toxoid. When a horse gets wounded, the animal should have an immediate injection with the tetanus antitoxin; this should be sufficient to stop the disease from developing. Thoroughly cleanse and medicate all wounds. Pregnant mares should get a booster dose of the toxoid 4-6 weeks before foaling so the newborn wil get adequate antitoxin antibodies in the colostrum.

Notes: Death occurs when the respiratory system is affected. Clostridium tetani can only grow where there is no oxygen (anaerobic environment). There is a 50-60% fatality rate. Mild cases may recover in 8-10 weeks. People can also get tetanus if they get cut while working around horses or the stable area, so humans should also be vaccinated. Tetanus is not caused by the bacteria itself, but by the toxin the bacteria produce. The bacteria produce spores which are highly resistant to heat and chemicals and can live in the soil for years. It is not contagious.

To learn more about Tetanus: