Molecular Identification of Sarcocystis sp. (Apicomplexa, Sarcocystidae) in Offspring of Tengmalm's Owls, Aegolius funereus (Aves, Strigidae)

Abstract

<p><strong>Background:</strong> Birds act as intermediate or definitive hosts of cyst-forming coccidia parasites of the genus <em>Sarcocystis</em> Lankester, 1882. However, the spectrum of species of <em>Sarcocystis</em> in birds and the role of the latter in the transmission of coccidia are still incomplete for many avian species, including the Tengmalm's owl <em>Aegolius funereus</em> (Linnaeus, 1758). During the research on Tengmalm's owls in Finland, some fledglings were found dead and subsequently parasitologically examined. Therefore, this study is focused on the morphological and molecular description of a <em>Sarcocystis</em> species found in the intestine of the Tengmalm's owl and its possible role as a definitive host.<br></p><p><strong>Methods:</strong> Eleven fledgling owls in the Kauhava region of west-central Finland were found dead and subsequently were submitted for necropsy and parasitologically examined through the flotation–centrifugation coprological technique for the presence of oocysts/sporocysts of the genus <em>Sarcocystis</em> by light microscopy. Wet mounts were used for the examination of muscle samples (breast, legs, and heart). Polymerase chain reaction (PCR) and nested-PCR were carried out using primers for 18S rRNA, 28S rRNA, ITS1 region, and CO1 genes.</p><p><strong>Results:</strong> All 11 examined owls were parasitized by numerous sporocysts and oocysts in the intestinal mucosa scrapings (prevalence, 100%). Sporulated oocysts and sporocysts measured 16.34–16.96 × 11.47–12.09 μm and 11.85–13.52 × 7.77–9.25 μm, respectively. The skeletal and heart muscles were negative for sarcocysts. <em>Sarcocystis</em> sp. ex <em>Aegolius funereus</em> (hereafter <em>Sarcocystis</em> sp. Af) is closely related to <em>Sarcocystis strixi</em> in the barred owl (<em>Strix varia</em> Barton, 1799) from the USA and <em>Sarcocystis</em> sp. isolate 5 in the European shrew (<em>Sorex araneus</em> Linnaeus, 1758) from the Czech Republic. Phylogenetic analysis allowed determining the relationship of the herein reported <em>Sarcocystis</em> sp. with its congeners.</p><p><strong>Conclusions:</strong> This work provided the first and most comprehensive record on <em>Sarcocystis</em> from owls obtained in Finland, thus highlighting the importance of molecular data in species identification.</p>