Horse Diseases & Conditions

When a horse begins acting abnormally, it is important to ascertain the exact cause of the eccentricity. Odd horse behavior is frequently an indication of illness. Some horse diseases and conditions can turn lethal in a matter of days. Knowing which diseases and conditions to look for can often save the life of the horse when they are treated quickly and appropriately.

Equine encephalomyelitis, more commonly known as sleeping sickness, is a viral horse disease transmitted predominately through mosquitoes. There are several strains of equine encephalomyelitis, but all of these horse diseases manifest in a very similar manner. First the affected horse will run a moderate fever for several days while appearing tired and depressed. Eventually the horse will begin to walk clumsily, go blind, grind its teeth and yawn frequently. Many infected horses will perish as a result of the disease. Those who survive frequently do so with impaired mental functionality. The best method of prevention is strong mosquito control.

Equine infectious anemia (EIA) is transmitted from infected horses to healthy horses through blood transfers. This can happen through parasitic insect bites, hypodermic needles and contaminated bits. EIA is a viral disease that attacks the red blood cells of the horse, thus causing anemia. Occasionally EIA will kill a horse in only a fortnight. However, many horses will develop a chronic condition where they may relapse even years later. Some horses will recover completely, but these horses are still carriers of the disease and can transmit it to other horses.

HERDA stands for hereditary equine regional dermal asthenia. This genetic skin disease often appears in adulthood once a horse begins saddle training. HERDA causes the skin to scar and break easily, which prevents horses from being ridden. This incurable condition frequently results in euthanasia as the horse is not fit for either breeding or riding. However, HERDA itself is not considered a fatal condition. To diagnose HERDA accurately, a DNA test is required. The University of California Davis Veterinary Genetics Laboratory reports that an estimated 50 percent of all foals are carriers of HERDA. For this reason it is crucial that all horse breeders test all horses for the disease.

Strangles is a common horse disease that appears to be a cold or the flu. This horse disease is passed through the saliva of infected horses, most commonly through shared feed. Strangles is a respiratory infection that causes a swelling of the horse's lymph nodes, fever, nasal discharge and depression. Typically horses with strangles will recover completely, but occasionally the disease will result in organ damage and death. To prevent transmission, clean feeding and water troughs thoroughly and frequently.

Protozoal myeloencephalitis is a horse condition caused by a parasitic protozoa infection. This parasite is ingested by the horse through feces of infected animals like birds and rodents. Equine protozoal myeloencephalitis is usually detectable only through a blood test. However, this parasitic disease can cause a neurologic condition in which the infected horse's eyes will droop, the horse will appear uncoordinated and will eventually die. However, if this condition is caught early, there are several antibiotic treatments that have proven effective.