Molecular characterisation of Sarcocystis lutrae n. sp. and Toxoplasma gondii from the musculature of two Eurasian otters (Lutra lutra) in Norway

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• 作者：Bj?rn Gjerde ; Terje D. Josefsen
• 关键词：Eurasian otter ; Lutra lutra ; Sarcocystis lutrae ; Sarcocystis arctica ; Toxoplasma gondii ; Arctic fox ; Vulpes lagopus ; Muscular sarcocystosis ; Toxoplasmosis ; Norway ; Phylogeny ; 18S rRNA ; 28S rRNA ; ITS1 ; cox1 ; cytb
• 刊名：Parasitology Research
• 出版年：2015
• 出版时间：March 2015
• 年：2015
• 卷：114
• 期：3
• 页码：873-886
• 全文大小：1,210 KB
• 参考文献：1. Chadwick EA, Cable J, Chinchen A, Francis J, Guy E, Kean EF, Paul SC, Perkins SE, Sherrard-Smith E, Wilkinson C, Forman DW (2013) Seroprevalence of / Toxoplasma gondii in the Eurasian otter ( / Lutra lutra) in England and Wales. Parasite Vectors 6:75. doi:10.1186/1756-3305-6-75 CrossRef
  2. Dahlgren SS, Gjerde B (2010) Molecular characterization of five / Sarcocystis species in red deer ( / Cervus elaphus), including / Sarcocystis hjorti n. sp., reveals that these species are not intermediate host specific. Parasitology 137:815-40. doi:10.1017/S0031182009991569 CrossRef
  3. Dubey JR, Rosypal AC, Rosenthal BM, Thomas NJ, Lindsay DS, Stanek JF, Reed SM, Saville WJ (2001) / Sarcocystis neurona infections in sea otter ( / Enhydra lutris): evidence for natural infections with sarcocysts and transmission of infection to opossums ( / Didelphis virginiana). J Parasitol 87:1387-393. doi:10.1645/0022-3395(2001)087[1387:SNIISO]2.0.CO;2 CrossRef
  4. Dubey JP, Lindsay DS, Rosenthal BM, Thomas NJ (2003) Sarcocysts of an unidentified species of / Sarcocystis in the sea otter ( / Enhydra lutris). J Parasitol 89:397-99. doi:10.1645/0022-3395(2003)089[0397:SOAUSO]2.0.CO;2 CrossRef
  5. Dubey JP, Reichard MV, Torretti L, Garvon JM, Sundar N, Grigg ME (2010) Two new species of / Sarcocystis (Apicomplexa: Sarcocystidae) infecting the wolverine ( / Gulo gulo) from Nunavut, Canada. J Parasitol 96:972-76. doi:10.1645/GE-2412.1 CrossRef
  6. Dubey JP, Sykes JE, Shelton GD, Sharp N, Verma SK, Calero-Bernal R, Viviano J, Sundar N, Khan A, Grigg ME (2014) / Sarcocystis caninum and / Sarcocystis svanai n. spp. (Apicomplexa: Sarcocystidae) associated with severe myositis and hepatitis in the domestic dog ( / Canis familiaris). J Eukaryot Microbiol. doi:10.1111/jeu.12182
  7. Gerhold RW, Howerth EW, Lindsay DS (2005) / Sarcocystis neurona-associated meningoencephalitis and description of intramuscular sarcocysts in a fisher ( / Martes pennanti). J Wildl Dis 41:224-30. doi:10.7589/0090-3558-41.1.224 CrossRef
  8. Gjerde B (2013a) Characterisation of full-length mitochondrial copies and partial nuclear copies (numts) of the cytochrome b and cytochrome c oxidase subunit I genes of / Toxoplasma gondii, / Neospora caninum, / Hammondia heydorni and / Hammondia triffittae (Apicomplexa: Sarcocystidae). Parasitol Res 112:1493-511. doi:10.1007/s00436-013-3296-4 CrossRef
  9. Gjerde B (2013b) Phylogenetic relationships among / Sarcocystis species in cervids, cattle and sheep inferred from the mitochondrial cytochrome c oxidase subunit I gene. Int J Parasitol 43:579-91. doi:10.1016/j.ijpara.2013.02.004 CrossRef
  10. Gjerde B (2014a) / Sarcocystis species in red deer revisited: with a re-description of two known species as / Sarcocystis elongata n. sp. and / Sarcocystis truncata n. sp. based on mitochondrial / cox1 sequences. Parasitology 141:441-52. doi:10.1017/S0031182013001819 CrossRef
  11. Gjerde B (2014b) Morphological and molecular characteristics of four / Sarcocystis spp. in Canadian moose ( / Alces alces), including / Sarcocystis taeniata n. sp. Parasitol Res 113:1591-604. doi:10.1007/s00436-014-3806-z CrossRef
  12. Gjerde B (2014c) Molecular characterisation of / Sarcocystis rileyi from a common eider ( / Somateria mollissima) in Norway. Parasitol
• 作者单位：Bj?rn Gjerde (1)
  Terje D. Josefsen (2)
  
  1. Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 8146 Dep., 0033, Oslo, Norway
  2. Norwegian Veterinary Institute—Troms?, Troms?, Norway
  
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Biomedicine
  Medical Microbiology
  Microbiology
  Immunology
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1955

文摘

Sarcocysts were detected in routinely processed histological sections of skeletal muscle, but not cardiac muscle, of two adult male otters (Lutra lutra; Mustelidae) from northern Norway following their post-mortem examination in 1999 and 2000. The sarcocysts were slender, spindle-shaped, up to 970?μm long and 35-0?μm in greatest diameter. The sarcocyst wall was thin (?.5?μm) and smooth with no visible protrusions. Portions of unfixed diaphragm of both animals were collected at the autopsies and kept frozen for about 14?years pending further examination. When the study was resumed in 2013, the thawed muscle samples were examined for sarcocysts under a stereo microscope, but none could be found. Genomic DNA was therefore extracted from a total of 36 small pieces of the diaphragm from both otters, and samples found to contain Sarcocystidae DNA were used selectively for PCR amplification and sequencing of the nuclear 18S and 28S ribosomal (r) RNA genes and internal transcribed spacer 1 (ITS1) region, as well as the mitochondrial cytochrome b (cytb) and cytochrome c oxidase subunit 1 (cox1) genes. Sequence comparisons revealed that both otters were infected by the same Sarcocystis sp. and that there was no genetic variation (100?% identity) among sequenced isolates at the 18S and 28S rRNA genes (six identical isolates at both loci) or at cox1 (13 identical isolates). PCR products comprising the ITS1 region, on the other hand, had to be cloned before sequencing due to intraspecific sequence variation. A total of 33 clones were sequenced, and the identities between them were 97.9-9.9?%. These sequences were most similar (93.7-6.0?% identity) to a sequence of Sarcocystis kalvikus from the wolverine in Canada, but the phylogenetic analyses placed all of them as a monophyletic sister group to S. kalvikus. Hence, they were considered to represent a novel species, which was named Sarcocystis lutrae. Sequence comparisons and phylogenetic analyses based on sequences of the 18S and 28S rRNA genes and cox1, for which little or no sequence data were available for S. kalvikus, revealed that S. lutrae otherwise was most closely related to various Sarcocystis spp. using birds or carnivores as intermediate hosts. The cox1 sequences of S. lutrae from the otters were identical to two sequences from an arctic fox, which in a previous study had been assigned to Sarcocystis arctica due to a high identity (99.4?%) with the latter species at this gene and a complete identity with S. arctica at three other loci when using the same DNA samples as templates for PCR reactions. Additional PCR amplifications and sequencing of cox1 (ten sequences) and the ITS1 region (four sequences) using four DNA samples from this fox as templates again generated cox1 sequences exclusively of S. lutrae, but ITS1 sequences of S. arctica, and thus confirmed that this arctic fox had acted as intermediate host for both S. arctica and S. lutrae. Based on the phylogenetic placement of S. lutrae, the geographical location of infected animals (otters, arctic fox) and the distribution of carnivores/raptors which may have interacted with them, the white-tailed eagle (Haliaeetus albicilla) seems to be a possible definitive host of S. lutrae. Some of the muscle samples from both otters were shown to harbour stages of Toxoplasma gondii through PCR amplification and sequencing of the entire ITS1 region (five isolates) and/or the partial cytb (eight isolates) and cox1 (one isolate). These sequences were identical to several previous sequences of T. gondii in GenBank. Thus, both otters had a dual infection with S. lutrae and T. gondii.