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Stephen Atkinson

Associate Professor (Senior Research)
Department of Microbiology

Stephen Atkinson

Associate Professor (Senior Research)
Department of Microbiology


My research focuses on fish parasites, specifically myxozoans. These are microscopic animals related to corals and jellyfish, but which are parasites that require two hosts to complete their life cycles. I investigate the structure, function, development and genetics of problematic myxozoans of salmon and trout, and discover and describe new parasite species.

Current research projects

Klamath River fish health studies

As part of a Bureau of Reclamation grant to Dr. Bartholomew and Dr. Hallett, we are undertaking several core studies: parasite detection and quantification in river water samples; genomics and transcriptomics of the primary parasite of concern, Ceratonova shasta; hunting for cryptic sources of parasites in the river basin; characterization and detection of the invertebrate host.

Novel approaches for preventing Myxozoan infection in fish

Together with Jerri Bartholomew and Tamar Lotan (U. Haifa, Israel), and grad students Ben Americus and Laila Brubaker, we are working to understand the fundamental structural and functional workings of myxozoan parasite spores: how they are built, if they can envenomate their hosts, and what types of chemical compounds can block their ability to detect and infect hosts.

Other ongoing research collaborations include

  • Microscopy and genetics of myxozoan mitochondria with Dorothee Huchon (Tel Aviv University, Israel).
  • Discovering cryptic life cycles of marine myxozoan parasites, with Isaure DeBuron, College of Charleston, SC.
  • Discovering novel myxozoan parasites of Amazonian fishes, with Maria Muller and Edson Adriano, U. Sao Paulo, Brazil.
  • Investigating composition of myxozoan spores with Ben Americus (Micro), Maria Muller (U. Sao Paulo), Tamar Lotan (U. Haifa), Chris Russo (OSU CEOS) & Joan Hudson (OSU EM facility).

Science and art

I use my scientific research to inspire artistic interpretations and representations for my own enjoyment, and to promote outreach and engagement with the wider community. I use paint, paper collage, digital illustration and 3D printing. I am one of 3 faculty advisors (with Jerri Bartholomew and Andrew Myers), of the interdisciplinary student group Seminarium. This group engages students with cross-disciplinary approaches to create exhibitions on campus and for the general public.


  • Müller, Maria I., Rayline T. A. Figueredo, Stephen D. Atkinson, Jerri L. Bartholomew, and Edson A. Adriano. 2023. "Henneguya correai n. sp. (Cnidaria, Myxozoa) Parasitizing the Fins of the Amazonian Fish Semaprochilodus insignis" Diversity 15, no. 6: 702. 10.3390/d15060702
  • Yang C, Huang Y, Atkinson SD, Bartholomew JL, Ma H, Zhao Y (2023) Morphological and genetic analysis of Ceratomyxa saurida Zhao et al. 2015 and Ceratomyxa mai n. sp. (Myxozoa: Ceratomyxidae) from the East China Sea. International Journal of Systematic and Evolutionary Microbiology
  • Bartholomew JL, Alexander JD, Hallett SL, Alama-Bermejo G, Atkinson SD (2022). Ceratonova shasta: a cnidarian parasite of annelids and salmonids. Parasitology 149, 1862–1875. 10.1017/S0031182022001275
  • Guo Q, Atkinson SD, Xiao B, Zhai Y, Bartholomew JL, Gu Z (2022) A myxozoan genome reveals mosaic evolution in the oldest-known metazoan parasite group. BMC Biol 20, 51. DOI:10.1186/s12915-022-01249-8
  • Alama-Bermejo G, Bartosova-Sojkova P, Atkinson SD, Holzer AS, Bartholomew JL (2022) Proteases as Therapeutic Targets Against the Parasitic Cnidarian Ceratonova shasta: Characterization of Molecules Key to Parasite Virulence In Salmonid Hosts, Frontiers in Cellular and Infection Microbiology (11) DOI:10.3389/fcimb.2021.804864
  • Americus, B., Hams, N., Klompen, A.M.L., Alama-Bermejo, G., Lotan, T., Bartholomew, J.L., and Atkinson, S.D. Accepted September 2021. The cnidarian parasite Ceratonova shasta utilizes inherited and recruited venom-like compounds during infection. PeerJ.
  • Alama-Bermejo, G., Hernandez-Orts, J.S., Huchon, D., and Atkinson, S.D. 2021. Two novel myxosporean parasite species of Ceratomyxa Thélohan, 1892 from the banded cusk-eel Raneya brasiliensis (Kaup) (Ophidiiformes: Ophidiidae) off Patagonia, Argentina. Parasitol. Intl. 85:102433.
  • Pekmezi, G.Z., Atkinson, S.D., Yardimci, B., Bolukbas, C.S., Ozppicak, M., and Yilmaz, S. 2021. Novel and known myxobolids (Cnidaria: Myxozoa) infecting Chondrostoma angorense (Cypriniformes: Leuciscidae) in Turkey. Parsitol. Intl. 83:102339.
  • Brekhman, V., Ofek-Lalzar, M., Atkinson, S.D., Alama-Bermejo, G., Maor-Landaw, K., Malik, A., Bartholomew, J.L., and Lotan, T. 2021. Proteomic analysis of the parasitic Cnidarian Ceratonova shasta (Cnidaria: Myxozoa) reveals diverse roles of actin in motility and spore formation. Front. in Mar. Sci. 8:632700.
  • Americus, B., Schisler, G.J., Bartholomew, J.L., and Atkinson, S.D. 2021. Myxobolus cerebralis Causes Presporogonic Mortality in Juvenile Mountain Whitefish J. of Aquatic Animal Hlth. 33(2):116-122.
  • Bartošová-Sojková, P., Kyslík, J., Alama-Bermejo, G., Hartigan, A., Atkinson, S.D., Bartholomew, J.L., Picard-Sánchez, A., Palenzuela, O., Faber, M.N., Holland, J.W., and Holzer, A.S. 2021. Evolutionary Analysis of Cystatins of Early-Emerging Metazoans Reveals a Novel Subtype in Parasitic Cnidarians Biology 10(2):110.
  • Americus, B., Bartholomew, J.L., Lotan, T., Atkinson, S.D. 2020. A comparison of the structure and function of nematocysts in free-living and parasitic cnidarians (Myxozoa). Inter. J. for Parasitol., 50: 763-769. DOI:10.1016/j.ijpara.2020.04.012.
  • Americus, B., Austin, B., Lotan, T., Bartholomew, J., and Atkinson, S. 2020. In vitro and in vivo assays reveal that cations affect nematocyst discharge in Myxobolus cerebralis (Cnidaria: Myxozoa). Parasitol., 147(12):1352-1358. DOI:10.1017/S0031182020001158.
  • Kyger, R., Luzuriaga, A., Peri, S., Layman, T., Sandberg, T.O.M., Singh, D., Atkinson, S.D., Bartholomew, J.L., Huchon, D., Soojin, V., and Alvarez-Ponce, D. 2020. Myxosporea (Myxozoa, Cnidaria) lack DNA cytosine methylation. Molec. Biol. and Evol.. msaa214. DOI:10.1093/molbev/msaa214.
  • Tilic, E., Atkinson, S.D., and Rouse, G. 2020. Mitochondrial genome of the freshwater annelid Manayunkia occidentalis Mitochondrial DNA Part B: Resources, 5(3): 3313-3315. DOI:10.1080/23802359.2020.1815604.
  • Alama-Bermejo, G., Meyer, E., Atkinson, S.D., Holzer, A.S., Wiśniewska, M.W., Kolísko, M., and Bartholomew, J.L. 2020. Transcriptome-wide comparisons and virulence gene polymorphisms of host-associated genotypes of the cnidarian parasite Ceratonova shasta in salmonids. Genome Biol. and Evol., 12(8), 1258-1276. DOI:10.1093/gbe/evaa109.
  • Borkhanuddin, M.H., Goswami, U., Cech, G., Molnár, K., Atkinson, S.D., and Székely, C. 2020. Description of myxosporeans (Cnidaria: Myxozoa) infecting the popular food fish Notopterus notopterus (Pisces: Notopteridae) in Malaysia and India. Food and Waterborne Parasitol. DOI:10.1016/j.fawpar.2020.e00092.
  • Yahalomi, D., Atkinson, S.D., Neuhof, M., Chang, E.S., Philippe, H., Cartwright, P., Bartholomew, J.L., and Huchon, D. 2020. A cnidarian parasite of salmon (Myxozoa: Henneguya) lacks a mitochondrial genome. PNAS, 117(10):5358-5363.
  • Atkinson, S.D., Bartholomew, J.L., and Rouse, G.W. 2020. The invertebrate host of salmonid fish parasites Ceratonova shasta and Parvicapsula minibicornis (Cnidaria) is a novel fabriciid annelid. Manayunkia occidentalis sp. nov. (Sabellida: Fabriciidae). Zootaxa, 4751(2):310-320.
  • Milanin, T., Bartholomew, J.L., and Atkinson, S.D. 2020. An introduced host with novel and introduced parasites: Myxobolus spp. (Cnidaria:Myxozoa) in yellow perch Perca flavescens. Parasitol. Res. DOI:10.007/S00436-019-06585-3.
  • Richey, C.A., Kenelty, K.V., Van Stone Hopkins, K., Stevens, B.N., Martínez-López, B., Barnum, S.M., Stevens, B.N., Hallett, S.L., Atkinson, S.D., Bartholomew, J.L., and Soto, E. 2020. Validation of environmental DNA sampling for determination of Ceratonova shasta (Cnidaria: Myxozoa) distribution in Plumas National Forest, CA. Parasitol. Res. 10.1007/s00436-019-06509-1.