Molecular characterization of Blastocystis and Entamoeba of muskoxen and sheep in Greenland

Authors: STENSVOLD, CHRISTEN - Staten Serum Institute; BERG, REBECCA - Staten Serum Institute; Maloney, Jenny; Molokin, Aleksey; Santin-Duran, Monica

Submitted to: International Journal for Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2023
Publication Date: 6/22/2023
Citation: Stensvold, C.R., Berg, R.P., Maloney, J.G., Molokin, A., Santin, M. 2023. Molecular characterization of Blastocystis and Entamoeba of muskoxen and sheep in Greenland. International Journal for Parasitology. 53(11-12):673-685. https://doi.org/10.1016/j.ijpara.2023.05.005 .
DOI: https://doi.org/10.1016/j.ijpara.2023.05.005

Interpretive Summary: Entamoeba spp. and Blastocystis sp. are among the most common parasites of humans and other animals all over the world. Molecular characterization of these parasites that are shared among human and non-human hosts can help shed light on the epidemiology and inform studies that aim to unravel the role of these organisms in health and disease. Here, we present the first data on genetic diversity of these two genera in Greenland. DNAs extracted from fecal samples from 243 muskoxen and 44 sheep were submitted to metabarcoding of nuclear small subunit ribosomal DNA. Molecular characterization of Entamoeba and Blastocystis sequences was conducted to determine their subtype and ribosomal lineage level. Using MinION-based sequencing, near-complete nuclear small subunit ribosomal DNA sequences were obtained from four fecal samples. Of the 243 muskox samples, 180 (74%) and 19 (8%) were positive for Blastocystis and Entamoeba, respectively. Forty (91%) and six (14%) of the 44 sheep samples were positive for Blastocystis and Entamoeba, respectively. Blastocystis subtypes (ST) 10, 14, 21, 24-26, and a novel subtype (ST40) were identified. Presence of more than one subtype was common. ST40 was frequent in muskoxen but limited to Northeast Greenland. Entamoeba bovis and the E. bovis-associated ribosomal lineages (RL) 1 and 8 were found, and three conditional lineages (CL3, CL4, and CL10) were confirmed; CL10 was promoted to RL12. Several novel lineages were identified, all of which were linked to the E. bovis complex. Blastocystis was far more common than Entamoeba and found in approximately three of every four animals indicating that its presence in large herbivorous mammals in Greenland is widespread. Multiple subtypes/lineages of both parasites were commonly observed, some of which were novel, but most of which are seen in many other parts of the world. Data presented here expand our knowledge on the epidemiology, host range, and molecular diversity of Blastocystis and Entamoeba that will be useful to other scientists, veterinarians, wildlife biologists, and public health agencies in understanding the current status of taxonomy, epidemiology, zoonotic potential, and public health importance of these protists.

Technical Abstract: Molecular characterisation of parasites that are shared among human and non-human hosts can help shed light on the epidemiology and inform studies that aim to unravel the role of these organisms in health and disease. Two of the most common of shared parasites include the single-celled intestinal parasitic protists Blastocystis and Entamoeba. Here, we present the first data on genetic diversity and host specificity of these two genera in Greenland. Faecal DNAs from 243 muskoxen and 44 sheep were submitted to metabarcoding of nuclear small subunit ribosomal DNA. Entamoeba and Blastocystis-specific sequences were clustered and consensus sequences subjected to taxonomic query. Using MinION-based sequencing, near-complete nuclear small subunit ribosomal DNA sequences were obtained from four faecal samples. Of the 243 muskox samples, 180 (74%) and 19 (8%) were positive for Blastocystis and Entamoeba, respectively. Forty (91%) and six (14%) of the 44 sheep samples were positive for Blastocystis and Entamoeba, respectively. Blastocystis subtypes (ST) 10, 14, 21, 24-26, and a novel subtype (ST40) were identified. Colonisation by more than one subtype was common. ST40 was common in muskoxen but limited to Northeast Greenland. Entamoeba bovis and the E. bovis-associated ribosomal lineages (RL) 1 and 8 were found, and three conditional lineages (CL3, CL4, and CL10) were confirmed; CL10 was promoted to RL12. Several novel lineages were identified, all of which were linked to the E. bovis complex. In conclusion, Blastocystis was far more common than Entamoeba and found in approximately three of every four animals; both can be considered common colonisers of large herbivorous mammals in Greenland. Multiple subtypes/lineages of both parasites were commonly observed, some of which were novel, but most of which are seen in many other parts of the world.