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Equine Protozoal Myeloencephalitis (view source)
Revision as of 20:37, 8 July 2010
, 20:37, 8 July 2010no edit summary
====Treatment====
====Treatment====
Antiprotozoals
Sulphonamide drugs combined with pyrimethamine for synergism
Sulfadiazine and pyriemthamine PO SID 'Re-Balance' no longer available? - 61.5% improvement by one clinical grade, tx fro 90-270days
Complications: anaemia, leukopenia, neutropenia - usually self limiting, resolve with cessatrion of tx
Use of sulfadizine in breeding animals contorverisla but one study showed no effect on preganncy rates or EED
Sulfamthoxazole and pyrimethaine caused mild ataxia associated with mounting and ejaculation in a grp of pony stallions
Ponazuril (Marquis, Bayer Animal Health) - 1st FDA-approved drug for EPM, well absorbed PO, achieves steady state theraeutic concentration in 3days in CSF of hroses treated with 5mg/kg
The only FDA-approved treaments for EPM are ponazuril (5 mg/kg, PO, sid for 28 days) and nitazoxanide (50 mg/kg, PO, sid for 28 days), both as paste formulations. An alternative approach is the use of antifolate drugs, eg, sulfadiazine, or sulfamethoxazole (15-25 mg/kg, PO, sid-bid) in combination with pyrimethamine (1 mg/kg, PO, sid). The sulfonamide can be given with or without trimethoprim. Pyrimethamine must be given at least 1 hr before or after hay is fed. Treatment is usually continued for 6 mo. Anemia may develop after prolonged treatment with antifolate drugs and is best prevented by provision of high quantities of green forage. At least 60% of horses improve with treatment, but <25% recover completely. Relapses are common in horses that remain positive on immunoblot and rare in those that become negative.
The only FDA-approved treaments for EPM are ponazuril (5 mg/kg, PO, sid for 28 days) and nitazoxanide (50 mg/kg, PO, sid for 28 days), both as paste formulations. An alternative approach is the use of antifolate drugs, eg, sulfadiazine, or sulfamethoxazole (15-25 mg/kg, PO, sid-bid) in combination with pyrimethamine (1 mg/kg, PO, sid). The sulfonamide can be given with or without trimethoprim. Pyrimethamine must be given at least 1 hr before or after hay is fed. Treatment is usually continued for 6 mo. Anemia may develop after prolonged treatment with antifolate drugs and is best prevented by provision of high quantities of green forage. At least 60% of horses improve with treatment, but <25% recover completely. Relapses are common in horses that remain positive on immunoblot and rare in those that become negative.
No proven preventive is available. A conditionally approved vaccine is marketed, and its efficacy continues to be evaluated. There is interest in using antiprotozoal drugs for prevention; however, evidence-based protocols are not yet available. The source of infective sporocysts is probably opossum feces, so it is prudent to prevent access of opossums to horse-feeding areas. Horse and pet feed should not be left out; open feed bags and garbage should be kept in closed galvanized metal containers, bird feeders should be eliminated, and fallen fruit should be removed. Opossums can be trapped and relocated. Because putative intermediate hosts cannot be directly infective for horses, it is unlikely that control of these populations will be useful in EPM prevention.
No proven preventive is available. A conditionally approved vaccine is marketed, and its efficacy continues to be evaluated. There is interest in using antiprotozoal drugs for prevention; however, evidence-based protocols are not yet available. The source of infective sporocysts is probably opossum feces, so it is prudent to prevent access of opossums to horse-feeding areas. Horse and pet feed should not be left out; open feed bags and garbage should be kept in closed galvanized metal containers, bird feeders should be eliminated, and fallen fruit should be removed. Opossums can be trapped and relocated. Because putative intermediate hosts cannot be directly infective for horses, it is unlikely that control of these populations will be useful in EPM prevention.