The only Sarcocystis species currently known to inhabit the fibers of skeletal and cardiac muscles in horses are S. fayeri, S. bertrami, and S. asinus. We describe herein the invasion of myofibers in a horse by S. gigantea, a sheep-specific species with low virulence in the original host. A hunter gelding was referred to a veterinary surgeon in Newmarket (UK). The anamnestic data reported that the horse had an initial history of swelling of the right forelimb with fluid on the front of the carpus and edema spreading up the forearm. Subsequently, 2 firm lumps were found on the left pectoral muscle adjacent to the axilla of the left forelimb. Histologic examination of biopsies from the lumps revealed multifocal granulomatous eosinophilic myositis associated with intact and degenerate encysted parasites, consistent with Sarcocystis spp. Based on amplification and DNA sequencing of the 18S rRNA gene obtained from formalin-fixed, paraffin-embedded tissue blocks, S. gigantea was identified. The presence of sarcocysts in equine skeletal muscles has been considered an incidental finding, and there are only sporadic associated reports of myositis. Our finding suggests that some Sarcocystis spp. have a wider intermediate host range than believed previously, and that Sarcocystis of other species (not considered horse-associated) can invade the muscle fibers of equids, leading to myositis.

Sarcocystis gigantea infection associated with granulomatous eosinophilic myositis in a horse / Veronesi, F.; Di Palma, S.; Gabrielli, S.; Morganti, G.; Milardi, G. L.; Middleton, B.; Lepri, E.. - In: JOURNAL OF VETERINARY DIAGNOSTIC INVESTIGATION. - ISSN 1040-6387. - 32:4(2020), pp. 611-615. [10.1177/1040638720935847]

Sarcocystis gigantea infection associated with granulomatous eosinophilic myositis in a horse

Gabrielli S.;Milardi G. L.;
2020

Abstract

The only Sarcocystis species currently known to inhabit the fibers of skeletal and cardiac muscles in horses are S. fayeri, S. bertrami, and S. asinus. We describe herein the invasion of myofibers in a horse by S. gigantea, a sheep-specific species with low virulence in the original host. A hunter gelding was referred to a veterinary surgeon in Newmarket (UK). The anamnestic data reported that the horse had an initial history of swelling of the right forelimb with fluid on the front of the carpus and edema spreading up the forearm. Subsequently, 2 firm lumps were found on the left pectoral muscle adjacent to the axilla of the left forelimb. Histologic examination of biopsies from the lumps revealed multifocal granulomatous eosinophilic myositis associated with intact and degenerate encysted parasites, consistent with Sarcocystis spp. Based on amplification and DNA sequencing of the 18S rRNA gene obtained from formalin-fixed, paraffin-embedded tissue blocks, S. gigantea was identified. The presence of sarcocysts in equine skeletal muscles has been considered an incidental finding, and there are only sporadic associated reports of myositis. Our finding suggests that some Sarcocystis spp. have a wider intermediate host range than believed previously, and that Sarcocystis of other species (not considered horse-associated) can invade the muscle fibers of equids, leading to myositis.
2020
sarcocystis gigantea; eosinophilic myositis; horses; animals; horse diseases; horses; male; muscular dystrophies, limb-girdle; myositis; rna, protozoan; rna, ribosomal, 18s; sarcocystis; sarcocystosis; sequence analysis, dna
01 Pubblicazione su rivista::01i Case report
Sarcocystis gigantea infection associated with granulomatous eosinophilic myositis in a horse / Veronesi, F.; Di Palma, S.; Gabrielli, S.; Morganti, G.; Milardi, G. L.; Middleton, B.; Lepri, E.. - In: JOURNAL OF VETERINARY DIAGNOSTIC INVESTIGATION. - ISSN 1040-6387. - 32:4(2020), pp. 611-615. [10.1177/1040638720935847]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1494939
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