In order to complete its life cycle this parasite needs two hosts, a definitive and an intermediate. Usually the signs are worse in a localized area or on the left or right side. One in the definitive host a carnivore like the opossum and one in a secondary or intermediate host wild birds that the opossum feeds on.
The protozoa are usually very host specific requiring a specific carnivore to reproduceand most likely neither host show any clinical signs of disease. The life cycle of S. Prevention is also important. The exposure can occur through grazing or eating contaminated feed or drinking contaminated water.
Apparent lameness, particularly atypical lameness or slight gait asymmetry of the rear limbs are commonly caused by EPM. The opossum is the definitive host of the disease, passing the parasite through feces. Schizonts, in various stages of maturation, or free merozoites commonly are seen in the cytoplasm of neurons or mononuclear phagocytes.
The exercise level is dictated by the stability of the horse and the opinions of both the examining veterinarian and the owner. These drugs minimize the infection but do not kill the parasite.
If left undiagnosed and untreated, EPM can cause devastating and lasting neurological damage. Any cranial nerve nucleus may be involved, and there may be seizures, visual deficits including abnormal menace responses, or behavioral abnormalities.
Also parasitized are intravascular and tissue neutrophils and eosinophils and, more rarely, capillary endothelial cells and myelinated axons. Because the protozoa may infect any part of the CNS, almost any neurologic sign is possible.
Without treatment, EPM may progress to cause recumbency and death. EPM was first identified in the s, with development of improved diagnostic tests in the s.
This information was first published on Horsetalk. It is an antioxidant and is many times used to aid healing of nervous system tissues.
Recently, antiprotozoal treatments that kill the parasite and clear the infection have shown promise. Progression to recumbency occurs over hours to years and may occur steadily or in a stop-start fashion.
Actual signs may depend on the severity and location of the lesions that develop in the brain, brain stem or spinal cord. Loss of feeling in the face, neck and body Splay footed stance or leaning against objects for support Causes of Equine Protozoal Myeloencephalitis in Horses An organism that is a protozoal parasite, Sarcocustis neurona or Neospora hughesican, causes equine protozoal myeloencephalitis.
An early pioneer was J. Conversely, positive or high serum S neurona titers have limited diagnostic utility in that such titers do not clearly distinguish horses with subclinical extraneural infections from those with EPM.
Serologic tests for specific antibodies against whole S neurona eg, indirect fluorescent antibody test or S neurona surface antigens snSAGs provide evidence of current or recent exposure to the organism; thus, low or negative serum titers tend to exclude the diagnosis of EPM.
Immune stimulants have also been recommended and include products such as Propionibacterium acnes administration, mycobacterial cell wall extracts, oral levamisole, and alpha-interferon. Missouri… The horse is an unfortunate casualty in this cycle; it is infected when feces of the opossum are ingested with their food material.
Sarcocystis has a complex life cycle involving the opossum as definitive host, so it is more prevalent in areas where opossums live. It is thought that Sarcocystis neurona does not need to enter the CNS to cause disease, in some cases S. The disease usually begins insidiously but may present acutely and be severe at onset.
The Journal of Parasitology. Serial blood levels are helpful in guiding treatment. Horses with EPM involving the spinal cord have asymmetric or symmetric weakness and ataxia of one to all limbs, sometimes with obvious muscle atrophy.
Your veterinarian will prescribe the appropriate anti-protozoal medications for your horse. Additionally, a commercially available chemically inactivated vaccine of merozoites of S.
More commonly, neurologic signs occur acutely but also may progress gradually to a noticeable gait abnormality, functional impairment of one or more limbs, weakness, asymmetric muscle atrophy Photos 1 and 2,incoordination leaning to one sidehead tilt, stiffness, or severe ataxia, as a horse might suddenly fall over during a race or workout, without any previous apparent signs.
The disease is widespread throughout North and South America. EPM is seen only in parts of the world that are inhabited by opossum specifically the Americas.Equine Protozoal Myeloencephalitis Overview of Equine Protozoal Myeloencephalitis Equine protozoal myeloencephalitis (EPM) is a common neurologic disease of horses in the Americas; it has been reported in most of the contiguous 48 states of the USA, southern Canada, Mexico, and several countries in Central and South America.
Equine Protozoal Myeloencephalitis (EPM) is the most common neurologic disease seen in horses referred to Ohio State. In fact, more than 10% of equine cases presented to the Veterinary Medical Center at Ohio State have neurologic disease.
Treatment and Prognosis: Treatment of equine protozoal myeloencephalitis is expensive, and even mildly affected horses can require prolonged therapy. The standard treatment for many years has been combinations of antifolate drugs including sulfadiazine and pyrimethamine with or without trimethoprim.
Equine Protozoal Myeloencephalitis (EPM) is a master of disguise. This serious disease, which attacks the horse’s central nervous system, can be difficult to diagnose because its signs often mimic other health problems in the horse and signs can range from mild to severe.
Equine Protozoal Myeloencephalitis, Myelitis is the most common infectious cause of neurologic disease in horses. It is caused by one of two protozoal parasites (Sarcocystis neurona or Neospora hughesi), that attack the brain and/or spinal cord and damage the nerve tissue.
Sarcocystis neurona has been implicated in the disease for years. Equine Protozoal Myeloencephalitis: An Updated Consensus Statement with a Focus on Parasite Biology, Diagnosis, Treatment, and Prevention. Authors. S.M. Reed, Another disease which should be considered as a differential diagnosis is equine motor neuron disease (EMND).
Affected horses with early stages of disease typically have severe limb.Download