How Long Can a Horse Live With EPM?

EPM, or Equine Protozoal Myeloencephalitis, is a neurological disease that affects horses, caused by the protozoan Sarcocystis neurona or Neospora hughesi. Severe signs of this illness include ataxia, muscle wasting, weakness, paralysis, and in some instances, even death. As a horse owner, you may wonder how long your horse can live with EPM and what factors may influence its prognosis. This article will provide the latest information and insights based on scientific research and clinical experience.

Factors that Affect the Survival of Horses with EPM

The survival rate of horses with EPM can differ significantly based on a number of variables, including:

  • The seriousness of the clinical symptoms: Horses with modest to intermediate clinical symptoms, such as slight muscle atrophy or ataxia, may have a better prognosis than those with more severe symptoms, like the inability to stand or eat.
  • The timing of the diagnosis: Early detection and intervention can improve the prognosis of EPM by reducing nervous system harm and enhancing immune function. Late or missed diagnosis, however, can result in irreversible damage and poor response to therapy.
  • Treatment: The stage and severity of the disease determine the course of action, managing EPM involves the use of various medications such as antiprotozoals, anti-inflammatories, and immune modulators.
  • The duration of the treatment may range from weeks to months and may require repeated courses or maintenance therapy. The treatment’s choice and efficacy can affect the disease’s outcome.
  • The horse’s age, breed, and overall health status: Some horses may have a genetic predisposition or immune deficiency that can affect their susceptibility or resistance to EPM. In comparison to younger, healthy horses, older horses or horses who also have other illnesses, like metabolic disorders or infectious diseases, may have a reduced chance of survival.
Factors that Affect the Survival of Horses with EPM

Early Detection and Treatment of EPM in Horses

Early detection is key in treating EPM in horses. To look for disease symptoms, veterinarians can conduct a physical and neurological evaluation. Performing tests on the blood and cerebrospinal fluid can help determine the presence of the organism that causes EPM.

Antiprotozoal drugs, anti-inflammatory drugs, and supportive care practices like physical therapy are available as treatment choices. Following the veterinarian’s recommended treatment plan and monitoring the horse’s progress is important.

Prevention of EPM includes minimizing the horse’s exposure to contaminated feed and water, as well as regular cleaning and disinfection of stalls and feeding areas. With early detection and prompt treatment, horses with EPM can recover and return to normal activities.

Long-Term Management Strategies for EPM-Positive Horses

Horses diagnosed with EPM require long-term management strategies. While treatment can help to control the disease, there is no cure for EPM. Horses that have recovered from the initial infection may still experience flare-ups of symptoms in the future. To manage EPM-positive horses, it’s important to have a consistent monitoring plan in place. This may include regular veterinary check-ups, neurological exams, and blood work.

To support maintaining the horse’s general health, it’s also critical to provide a regular diet and activity schedule. Additionally, minimizing stress and making sure the environment is clean and secure can aid in preventing flare-ups and lower the risk of developing new infections. With proper long-term management, EPM-positive horses can lead happy and healthy lives.

The Prognosis for Horses with EPM: What to Expect

Depending on the severity of the condition and the promptness of therapy, the prognosis for horses with EPM can change. Horses diagnosed and treated early on have a better chance of a successful recovery.

Horses may, however, occasionally suffer from long-term neurological injury that affects their capacity to carry out specific tasks. It’s important to understand that there is no cure for EPM, and horses may experience flare-ups of symptoms even after successful treatment.

The sort of parasite that is causing the EPM infection will also affect the prognosis because some parasites are more challenging to treat than others. Horses that have recovered from EPM will need consistent monitoring and management to help prevent future flare-ups and maintain their overall health. Consult your veterinarian for more information on what to expect and how to manage your horse’s health.

Survival Rates and Prognostic Factors in Horses with EPM

  • Several studies have investigated horses’ survival rates and prognostic factors with EPM based on clinical, laboratory, and epidemiological data.
  • According to a 2010 research that was written up in the Journal of Veterinary Internal Medicine, horses with EPM had a median survival time of 256 days, with a range of 1 to 1836 days. The overall survival rate was 59% but varied depending on the signs’ severity and the treatment duration. Horses who received longer, more intensive therapy fared better than those who got shorter, less intensive treatment, and horses with mild to moderate signs had a higher survival rate than horses with severe signs.
  • A 2015 study that was released in the Journal of the American Veterinary Medical Association examined epidemiological and clinical information regarding EPM cases that occurred in the United States between 2000 and 2010. According to the research, the incidence of EPM varied by location, breed, age, and sex and was 2.8 cases per 10,000 horse years overall. The study also found that the survival rate of horses with EPM was 53% and that the survival was significantly affected by the breed, age, and duration of the clinical signs. Quarter Horses, Paint Horses, and Appaloosas had a lower survival rate than Thoroughbreds, Arabians, and Warmbloods, and older horses had a lower survival rate than younger horses. Horses with clinical signs lasting more than 30 days had a lower survival rate than those with shorter duration. Early diagnosis and treatment could improve the survival of horses with EPM and better management practices to prevent or reduce exposure to the causative agents.
Survival Rates and Prognostic Factors in Horses with EPM

How to Manage Horses with EPM?

If your horse has been diagnosed with EPM, working closely with your veterinarian will help you determine the best course of therapy and management. Here are some general guidelines that may help:

  • Follow the treatment plan as your veterinarian prescribes: Administer the medications as directed, and monitor your horse’s response and side effects. Only stop or change the treatment after consulting your veterinarian, as this may affect the outcome of the disease.
  • Provide supportive care and nutrition: Horses with EPM may require extra care and attention, such as bedding, padding, and feeding assistance. Ensure your horse has a balanced and palatable diet, and monitor their weight and hydration status. Consider adding supplements or probiotics that may help boost their immune system and gut health.
  • Reduce the risk of exposure to the causative agents: EPM is mainly transmitted through opossums, the definitive host of S. neurona. To minimize the risk of exposure, you may need to reduce or eliminate the access of opossums to your horse’s feed and water and keep your horse’s environment clean and dry. Consider using repellents or fencing to deter opossums from entering your property.
  • Monitor your horse’s condition and behavior: EPM can cause subtle or gradual changes in your horse’s gait, behavior, or performance. Monitor your horse’s condition and report any changes to your veterinarian. Keep a journal or video log of your horse’s progress, which may help track their response to the treatment and identify any relapses or setbacks.
How to Manage Horses with EPM?


The survival of horses with EPM can be affected by a number of variables, including the severity of the symptoms, the timing and type of treatment, the age and health state of the horse, and management practices. While the median survival time of horses with EPM is around 256 days, the survival rate can vary widely depending on the individual case.

By following the recommended guidelines for treatment and management and staying vigilant and proactive, you can help improve your horse’s prognosis with EPM and provide them with the best possible care and quality of life.


Q: Can horses recover from EPM?

A: Yes, horses can recover from EPM with early and effective treatment. However, some horses may experience long-term neurological deficits even after successful treatment.

Q: How is EPM in horses diagnosed?

A: To identify EPM, veterinarians use clinical symptoms, neurological examination, and laboratory tests such as blood and spinal fluid analysis.

Q: Do all horses have the same risk of developing EPM?

A: While some horses might have a hereditary propensity for EPM, others might have weakened immune systems that make them more prone to infection.

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