Equine Diseases: Alphabet Soup Simplified

Equine diseases, conditions, or problems are frequently referred to by their initials. Full names, a brief explanation of each condition, and management tips, if applicable, are given below.

CEM Contagious equine metritis. Inflammation of the female reproductive tract. Highly contagious. Mare shows discharge after breeding, fails to conceive. No signs in stallion.

COPD Chronic obstructive pulmonary disease (heaves). An allergic reaction to inhaled dust and mold spores in hay and bedding. Affected horses are exercise-intolerant. Control by wetting hay before feeding and removing horse from barn as much as possible.

CWD Chronic wasting disease. Fatal to deer and elk. Does not naturally affect cattle. Horses seem to be immune. Threat to humans possible but has not been proven.

DOD Developmental orthopedic disease. Any one of several conditions characterized by abnormal maturation of cartilage or bone. Some DOD can be prevented by proper nutrition of broodmares and encouraging steady moderate growth rates in young horses.

EEE Eastern equine encephalomyelitis. Viral disease that causes neurological symptoms in horses and humans. Usually fatal. Spread by mosquitoes, not by contact with an infected animal.

EGUS Equine gastric ulcer syndrome. Common in stall-kept horses such as those in training. Horses go off feed, may not want to work. Turning horses out on pasture is the most natural cure.

EHV Equine herpesvirus. Different types cause a range of signs including respiratory disease, neurologic deficits, and fetal loss.

EIA Equine infectious anemia (swamp fever). Spread by horseflies and deerflies. Affected horses may show fever, weight loss, swelling of tissue on the midline of the belly, anemia, and sometimes death. Diagnosed by a Coggins test that detects antibodies in the horse’s blood. No cure.

EIPH Exercise-induced pulmonary hemorrhage. In affected horses, strenuous exercise causes breakage of small blood vessels in the lungs. Some “bleeders” show a trickle of fresh blood from one or both nostrils after exercise. Precise cause has not been determined. Treatment with furosemide is often helpful.

EMND Equine motor neuron disease. Symmetrical paralysis, muscle atrophy, and weight loss are early signs of this fatal disease that is linked to high copper and low vitamin E concentrations in the spinal cord. Similar to Lou Gehrig’s disease in humans.

EPM Equine protozoal myeloencephalitis. Signs are stumbling, incoordination, asymmetrical muscle wasting. Caused by Sarcocystis neurona protozoa in the central nervous system.

PSSM Polysaccharide storage myopathy. A form of tying-up often seen in draft horses. Primary signs are severe stiffness and muscle cramping.

EVA Equine viral arteritis. Contagious disease that causes fever, respiratory disease, swelling of the face and legs, and abortion.

FMD Foot and mouth disease. Affects cattle and other animals with cloven hooves, causing weight loss due to mouth ulcers. Does not affect horses.

HYPP Hyperkalemic periodic paralysis. Genetic disease of stock-type horses. Affected horses may show loss of coordination, muscle spasms, collapse, or death. Limiting intake of potassium helps some horses lead more normal lives.

MRLS Mare reproductive loss syndrome. Term for conditions that caused abortions and neonatal foal deaths in Kentucky and Ohio in 2001 and 2002. Cause is still under investigation, but strongly associated with Eastern tent caterpillars.

OLWS OveroLethal white syndrome. Genetic disease of overo-patterned Paint horses. A foal inheriting the defect from both parents will colic and die within a few hours of birth. A DNA test can indicate whether breeding horses carry the mutation.

OCD Osteochondritis dissecans. A type of developmental orthopedic disease in which cartilage does not mature properly, causing various degrees of lameness in young horses

PHF Potomac horse fever. Bacterial disease causing fever, diarrhea, colic, founder, abortion, and sometimes death.

RER Recurrent equine rhabdomyolysis. A form of tying-up. Primary signs are severe stiffness, muscle cramping, and reluctance to move.

SCID Severe combined immunodeficiency. Genetic disease of Arabian horses. A foal receiving the defective gene from both parents dies within a few months of birth from massive respiratory infection.

SDF Synchronous diaphragmatic flutter (thumps). Condition seen in endurance horses that are severely dehydrated and depleted of electrolytes, especially calcium. Electrolyte imbalance makes the diaphragm contract each time the heart beats. Treated by administration of electrolytes and fluids.

VEE Venezuelan equine encephalomyelitis. Viral disease that causes neurological symptoms in horses and humans. May be fatal. Spread by mosquitoes, not by contact with an infected animal.

WEE Western equine encephalomyelitis. Viral disease that causes neurological symptoms in horses and humans. May be fatal. Spread by mosquitoes, not by contact with an infected animal.

WLD White line disease. Fungal and/or bacterial infection of the inner layers of the hoof wall. Damage to hoof layers and tissues can lead to lameness.

WNV West Nile virus. Introduced to the U.S. in the last few years, this virus causes weakness, stumbling, and other neurologic signs in horses, humans, and other animals. Infection is through bite of infected mosquitoes.