OVINE MYELOENCEPHALITIS-LEUKOMYELOMALACIA ASSOCIATED WITH A SARCOCYSTIS-LIKE PROTOZOAN

Bilateral pelvic limb paresis developed in 7 of 15 10-month-old Bluefa ce Leicester ram lambs on a mixed enterprise farm in the North of Engl and. Clinical signs were principally mild to severe paresis of the pel vic limbs. Two mildly affected lambs recovered. Multifocal spinal cord white matter edema and necrosis, glial nodules, and mild to moderate nonsuppurative encephalomyelitis were the principal findings in 3 seve rely paretic lambs examined histologically. Protozoan bodies (12.7-23. 0 mum) that stained immunocytochemically for Sarcocystis epitopes were in spinal cord glial cells of 2 of 3 lambs. Protozoa did not react im munocytochemically with anti-Toxoplasma gondii or Neospora canium anti sera. Serology indicated there was recent exposure to Sarcocystis spp. in some surviving lambs. These cases resembled those in previous repo rts of paresis due to an unidentified Sarcocystis-like protozoan in sh eep (ovine protozoan myeloencephalitis) in the British Isles, the USA, France, Australia, and New Zealand.