Avian Pathol.: A novel sarcocystis-associated encephalitis and myositis in racing pigeons.
Article Type: Report
Subject: Pigeons (Health aspects)
Encephalitis (Risk factors)
Encephalitis (Diagnosis)
Encephalitis (Research)
Sarcocystis (Complications and side effects)
Sarcocystis (Research)
Sarcocystis (Diagnosis)
Authors: Olias, P.
Gruber, A.D.
Heydorn, A.O.
Pub Date: 09/01/2009
Publication: Name: Journal of Avian Medicine and Surgery Publisher: Association of Avian Veterinarians Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Association of Avian Veterinarians ISSN: 1082-6742
Issue: Date: Sept, 2009 Source Volume: 23 Source Issue: 3
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: United States Geographic Code: 1USA United States
Accession Number: 252006992
Full Text: Sarcosporidian cysts in the skeletal muscle of domestic pigeons (Columba livia f. domestica) have previously been attributed to infection with Sarcocystis falcatula, which is shed in the feces of the opossum (Didelphis virginiana). We describe fatal spontaneous encephalitis and myositis associated with Sarcocystis infections in 3 flocks of racing pigeons with 47 of 244 animals affected. The clinical course was characterized by depression, mild diarrhea, torticollis, opisthotonus, paralysis, and trembling. Histopathologic examination of 13 pigeons revealed generalized severe granulomatous and necrotizing meningoencephalitis and myositis with sarcosporidian cysts. Light and transmission electron microscopy identified cysts in heart and skeletal muscle of 1-2 mm in length and 20-50 [micro]m in width. These were subdivided into small chambers by fine septae and filled with lancet-shaped cystozoites (7.5 x 1.5 [micro]m) and dividing metrocytes, which is characteristic for Sarcocystis. The cysts had smooth walls and were devoid of protrusions typical of S falcatula. Polymerase chain reaction amplification and sequencing of the internal transcribed spacer region (ITS-l) and the complete 28S rRNA identified a novel Sarcocystis species with only 51% ITS-I nucleotide sequence similarity with S falcatula. A phylogenetic comparison of the 28S rRNA revealed close sequence homologies with Frenkelia microti, Frenkelia glareoli, and Sarcocystis neurona. The clinical, histopathologic, electron microscopic, and genetic data are unlike any previously described protozoan infections in pigeons, suggesting a novel, severe disease due to an as yet undescribed Sarcocystis species.

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