Dr. Stephen Atkinson, Associate Professor (Senior Research)

Atkinson 1 Office  Nash Hall 546

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Phone  541-737-1861 Myxozoan spore types:  myxospores (top)
and actinospores (bottom)



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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.  Click on any image to enlarge.

Electron micrograph



(1)  Klamath River fish health studies (Bureau of Reclamation grant to Dr. Bartholomew and Dr. Hallett)

Parasite detection and quantification in river water samples
Genomics and transcriptomics of Ceratonova shasta
Hunting for cryptic sources of parasites
Characterization and detection of the invertebrate host

(2)  USDA Capacity Building Grant to Robert Durburow (KSU) and Stephen Atkinson (OSU)

We are developing computer learning games to promote awareness and education of fish diseases: Fish Detective and SimFish; with Dr. Sascha Hallett, u/g Paris Myers, Professor Yue Zhang and MS student Kevin Hung (OSU College of Electrical and Computer Engineering). We are also expanding fishpathogens.net, a database of fish diseases and pathogens, and a portal for connecting public inquiries with fish health experts; in collaboration with ODFW, undergraduate students and Dr. Sascha Hallett.

(3)    “A novel approach for preventing Myxozoan infection in fish: Control of polar capsule activation”

Together with Jerri Bartholomew and Tamar Lotan (U. Haifa, Israel), and grad student Ben Americus, 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 activation.

Other ongoing research collaborations include:

Microscopy and genetics of myxozoan mitochondria with Dorothee Huchon (Tel Aviv University, Israel).  Dual stained developing parasite cells.  Blue=DNA stained with DAPI.  Red=mitochondria stained with MitoTracker.  The blue nuclei are about 5 µm across.
Phylogenetics of Ceratonova shasta across the Pacific Northwest, with Rachel Breyta (OSU / USGS)
Discovering cryptic life cycles of marine myxozoan parasites, with Isaure DeBuron, College of Charleston, SC.
Novel and introduced myxozoan parasites, with Tiago Milanin, U. Sao Paulo, Brazil.




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 club Seminarium. The club engages students with cross-disciplinary approaches to create exhibitions on campus and for the general public. 

GRADUATE STUDENTS                

Ben Americus - PhD    

Ben is investigating the structure and function of stinging cells (nematocysts) in myxozoan parasites, using microscopy, transcriptomics, with in vitro and in vivo experiments.  Here he is conducting in vitro testing of the effects of different compounds on C. shasta spores.


David Lehrburger – Senior 2019-20   

I advised David with his 2019 SURE Science award project and OSU Honors thesis (Summer-Fall 2019) “Discovering the life cycle of Sphaerospora – a primitive parasite of Willamette River sticklebacks.”  Here David is sorting and examining potential worm hosts.

Paris Myers - Junior 2019-20

Paris is an accomplished artist and is part of the team to design and create the content for the two learning games in my USDA project.  Paris is compiling 35 mm slides for scanning and adding to our fish pathogens database.

Sophia Jadzak - graduated Spring 2019   

Sophia has worked with me and Dr Sascha Hallett to optimize an environmental water sampling assay for detection of the worm host of the myxozoan Ceratonova shasta. Sophia also performs the diagnostic qPCR assays for the parasite.  This is Sophia's SURE Project poster.

LilyAna Folk - graduated Spring 2019      

I worked with LilyAna to design assays to detect and sequence DNA from novel myxozoan parasites, and from cryptic cercozoans, which are single-celled animals present in groundwater (Professor Jan Spitsbergen).  Here LilyAna is examining an adult Chinook salmon for parasites.


I teach 2 courses in the OSU Honors College:   (1)  HC407: Life: The Biosphere through Space and Time.  (2)  HC407: Have Rocket Will Travel; and I co-teach the biannual summer salmon disease workshop.


Guo, Q., Atkinson, S.D., Xiao, B., Zhai, Y., Bartholomew, J.L., and Gu, Z.  2022.  A myxozoan genome reveals mosaic evolution in a  parasitic cnidarian.  BMC Biol. 20(1):51.

Alama-Bermejo, G., Bartosova-Sojkova, P., Atkinson, S.D., Holzer, A.S., and Bartholomew, J.L.    2022.   Proteases as Therapeutic Targets Against the Parasitic Cnidarian Ceratonova shasta: Characterization of Molecules Key to Parasite Virulence In Salmonid Hosts, Front. in Cellular and Infection Microbiol. (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.   2021.  The cnidarian parasite Ceratonova shasta utilizes inherited and recruited venom-like compounds during infection.  PeerJ 9:e12606.

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.

Breyta, R., Atkinson, S.D., and Bartholomew, J.L.  2019.   Evolutionary dynamics of Ceratonova species in the Klamath River basin reveals different host adaptation strategies.  Infection, Genetics and Evolution, 78:104081

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.  https://doi.org/10.1007/s00436-019-06509-1.

Alama-Bermejo, G., Viozzi, G.P., Waicheim, M.A., Flores, V.R., and Atkinson, S.D.  2019.  Host-parasite relationship of Ortholinea lauquen n. sp. (Cnidaria:Myxozoa) and the fish Galaxias maculatus (Jenyns, 1842) in Northwest Patagonia, Argentina.  Dis. Aquat. Organisms 136(2):163-174.

Borkhanuddin, M.H., Cech, G., Molnár, K., Shaharom-Harrison, F., Duy Khoa, T.N., Samshuri, M.A. Mazeland, S., Atkinson, S.D., and Székely, C.  2019.  Henneguya (Cnidaria:Myxosporea:myxobolidae) infections of cultured barramundi, Lates calcarifer (Perciformes:Latidae) in an estuarine wetlands system of Malaysia:  Description of Henneguya setiuensis n. sp., Henneguya voronini n. sp. and Henneguya calcarifer n. sp. Parasitol. Res. 119(1):85-96.

Atkinson, S.D., Hallett, S.L., Díaz Morales D., Bartholomew, J.L., and de Buron, I.   2019.  First myxozoan infection (Cnidaria: Myxosporea) in a marine polychaete from North America, and erection of actinospore collective group Saccimyxon. J. Parasitol. 105(2):252-262. DOI:10.1645/18-183

Fromm, A., Atkinson, S.D., Alama-Bermejo, G., Cartwright, P., Bartholomew, J., and Huchon, D.  2019.  A new mitochondrial gene order in the banded cusk-eel Raneya brasiliensis (Actinopterygii, Ophidiiformes). Mitochondrial DNA Part B, 4:1, 1-4

Howell, C.K., Atkinson, S.D., Bartholomew, J.L., and Hallett, S.L.  2019.  Development and application of a qPCR assay targeting Ichthyophthirius multifiliis in environmental water samples. Dis. Aquatic Org. 134; 43-55.


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