Morphological and molecular description of Sarcocystis ratti n. sp. from the black rat (Rattus rattus) in Latvia

• Published in: Parasitology research (1987) Vol. 118; no. 9; pp. 2689 - 2694
• Main Authors: Prakas, Petras, Kirillova, Viktorija, Gavarāne, Inese, Grāvele, Evita, Butkauskas, Dalius, Rudaitytė-Lukošienė, Eglė, Kirjušina, Muza
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2019; Springer; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Biomedicine; Bradyzoites; Cysts; definitive hosts; genetic variation; households; Immunology; intermediate hosts; internal transcribed spacers; Latvia; light microscopes; Medical Microbiology; Methylene blue; Microbiology; Muscles; Parasites; Phylogeny; Protozoology - Original Paper; rats; Rattus norvegicus; Rattus rattus; ribosomal DNA; Rodents; Sarcocystis; Sarcocysts; Skeletal muscle; Transmission electron microscopes; Lithuania; Canada; Latvia; Transmission electron microscopy; Phylogeny; rRNA; Black rat; cox1; Sarcocystis ratti
• ISSN: 0932-0113; 1432-1955; 1432-1955
• DOI: 10.1007/s00436-019-06393-9

Rodents have been widely studied as intermediate hosts of Sarcocystis ; however, only a few reports on these parasites in the black rat ( Rattus rattus ) are known. Having examined 13 black rats captured in Latvia, sarcocysts were found in skeletal muscles of two mammals and were described as Sarcocystis ratti n. sp. Under a light microscope, sarcocysts were ribbon-shaped, 0.9–1.3 × 0.09–0.14 mm in size and had a thin (0.8–1.3 μm) and smooth cyst wall. The lancet-shaped bradyzoites were 8.3 × 4.3 (7.5–9.3 × 3.9–4.8) μm. Under a transmission electron microscope, the cyst wall was up to 1.3 μm thick, wavy, the ground substance appeared smooth, type 1a-like. Morphologically, sarcocysts of S . ratti were somewhat similar to those of S . cymruensis , S . rodentifelis , and S . dispersa -like previously identified in the brown rat ( Rattus norvegicus ). On the basis of 18S rDNA, 28S rDNA, and cox1 , significant genetic differences (at least 2.3, 4.5, and 5.8%, respectively) were observed when comparing S . ratti with other Sarcocystis species using rodents as intermediate hosts. While ITS1 sequences of S . ratti were highly distinct from other Sarcocystis species available in GenBank. Phylogenetic and ecological data suggest that predatory mammals living near households are definitive hosts of S . ratti .