Dr. Jerri Bartholomew, Professor, Department Head,
Emile F. Pernot Distinguished Professorship
Director J.L. Fryer Aquatic Animal Health Laboratory
Research Interests: Salmon diseases, Myxozoan parasites, Host resistance mechanisms, Parasite evolution
Courses Taught: MB 491/591 Fish Disease, Salmonid Disease Workshop; MB 507 Seminar
Our research focuses on the pathogens that affect the health of wild Pacific salmon populations, particularly myxozoan parasites, which have a complex life cycle, requiring both a fish and annelid host.
Disease Effects on Wild Populations: The myxozoan Ceratomyxa shasta is endemic across the Pacific NW and causes high mortality in juvenile salmon in some river systems. A long-term project in the Klamath River integrates monitoring and research to develop recommendations for fishery management by providing real time data on parasite densities and their predicted effects on juvenile salmon, and by linking areas of high disease risk with physical parameters such as water flows and temperature. Research in the Willamette River further investigates C. shasta dynamics in this system as well as conducting surveys for parasites of native and introduced fishes.
Interactions Between Hatchery and Wild Fish: Research being conducted in the Willamette River basin investigates pathogen transmission between hatchery populations and naturally reproducing populations. We are also looking at the effects of multiple infections on salmon survival.
Climate Change Effects on Disease: Climate change is expected to have profound effects on host-pathogen interactions. We are examining how this might affect myxozoan disease by developing predictions for how the phenology of parasite life cycles will change under future climates, how changing flow dynamics will alter disease, and to identify river habitats that should be protected as refugia.
Parasite Evolution and Diversity: Myxozoans not only have complex life histories, but enigmatic relationships as revealed by molecular sequence analysis. Continued investigations into the genetics of C. shasta have revaled that it is actually a parasite complex, with different strains specifically evolving with different salmonid hosts. This finding has caused us to rethink assumptions about host-parasite interactions. We are currently involved in genome sequencing and transcriptomic studies that will aid us in developing better diagnostic tools as well as to answer questions about basic parasite biology and phylogenetic relationships.
Parasite Invasion: The first step in Myxozoan infection is activation of their polar capsules. These specialized cells resemble the nematocysts of their cnidarian relatives and could offer possibilities for development of therapeutants. We are working with Israeli scientists to understand the physical process and the genes that control it, as well as to test candidate treatments that affect the process.
Evolution of the Immune System and Role of Mucosal Immunity: This salmonid-C. shasta relationship has proved an ideal model for investigating mucosal immunity in a primitive host and is the basis for a collaboration with Oriol Sunyer, University of Pennsylvania, funded by the National Science Foundation and National Institutes of Health.
Roon, S.R., Alexander, J.D., Jacobson, K.C., and Bartholomew, J.L. 2015. Effect of Nanophyetus salmincola and bacterial co-infection on mortality of juvenile chinook salmon. J. Aquat. Animal Hlth. 4:209-16,
Hurst, C.N., Wong, P., Hallett, S.L., Ray, R.A., and Bartholomew. 2014. Transmission and persistence of Ceratomyxa shasta genotypes in chinook salmon. J. Parasitol. PMID: 24945751.
Ray, R.A., R.W. Perry, N.A. Som and J.L. Bartholomew. 2014. Using cure models for analyzing the influence of pathogens on salmon survival. Transactions of the American Fisheries Society. 143(2):
Atkinson, S.D., Foott, J.S., and Bartholomew, J.L. 2014. Erection of Ceratonova n. Gen. (Myxosporea: Ceratomyxidae) to encompass freshwater species C. gasterostea n. sp. from threespine stickleback (Gasterosteus aculeatus) and C. shasta n. comb. from salmonid fishes. J. Parasitol. PMID 24754344.
Adriano, E.A., Silva, M.R., Atkinson, S.D., Bartholomew, J.L., and Maia, A.A. 2014. Myxidium ceccarellii n. sp. (Myxosporea) from the gallbladder of Leporinus elongatus (Anastomidae) from the São Francisco River, Brazil. Parasitol. Res. PMID 24752369.
Bjork, S.J., Zhang, Y.A., Hurst, C.N., Alonso-Naveiro, M.E., Alexander, J.D., Sunyer, J.O., and Bartholomew, J.L. 2014. Defenses of susceptible and resistant Chinook salmon (Onchorhynchus tshawytscha) against the myxozoan parasite Ceratomyxa shasta. Fish Shellfish Immunol. 1:87-95.
Gómez, D., Bartholomew, J., and Sunyer, J.O. 2014. Biology and mucosal immunity to myxozoans. Dev. Comp. Immunol. 43(2): 243-56.
Polley, T.M., Atkinson, S.D., Jones, G.R., and Bartholomew, J.L. 2013. Supplemental description of Myxobolus squamalis (Myxozoa). J. Parasitol. 99:725-728.
Ray, A.R. and J.L. Bartholomew. 2013. Estimation of transmission dynamics of the Ceratomyxa shasta actinospore to the salmonid host. Parasitology. 140:907-916.
Bartošová, P., I. Fiala, M. Jirku, M. Cinkova, M. Caffara, M.L. Fioravante, S.D. Atkinson, J.L. Bartholomew and A.S. Holzer. 2013. Sphaerospora sensu stricto: Taxonomy, diversity and evolution of a unique lineage of myxosporeans (Myxozoa). Molec. Phylogentics and Evolution. 68:93-105.
Ray, A.R., R.A. Holt and J.L. Bartholomew. 2012. Relationship between temperature and C. shasta-induced mortality in Klamath River salmonids. Journal of Parasitology. 98:520-526.
Holzer, A.S., P. Bartošová, H. Pecková, T. Tyml, S. Atkinson, J. Bartholomew, D. Sipos, E. Eszterbauer and I. Dyková. 2013. Who's who in renal sphaerosporids (Bivalvulida: Myxozoa) from common carp, Prussian carp and goldfish -- Molecular identification of cryptic species, blood stages and new members of Sphaerospora sensu stricto. Parasitology. 140:40-60.
Ordás, M.C., R. Castro, B. Dixon, J.O. Sunyer, S. Bjork, J. Bartholomew, T. Korytar, B. Kollner, A. Cuesta and C. Tafalla. 2012. Identification of a novel CCR7 gene in rainbow trout with differential expression in the context of mucosal or systemic infection. Developmental and Comparative Immunology. 38:302-311.
Stinson, M.E.T. and J.L. Bartholomew. 2012. Predicted redistribution of Ceratomyxa shasta genotypes with salmonid passage in the Deschutes River, Oregon. J. of Aquatic Animal Hlth. 24:274-280.
Hallett, S.L., R.A. Ray, C.N. Hurst, R.A. Holt, G.R. Buckles, S.D. Atkinson and J.L. Bartholomew. 2012. Density of the waterborne parasite, Ceratomyxa shasta, and its biological effects on salmon. Applied and Environmental Microbiology 78:3724-3731.
Hurst, C.N., R.A. Holt and J.L. Bartholomew. 2012. Ceratomyxa shasta in the Williamson River, Oregon: Implications for reintroduced salmon. North American Journal of Fisheries Management. 32:14-23.
Atkinson, S.D., S.R.M. Jones, R.D. Adlard and J.L. Bartholomew. 2011. Geographic and host distribution patterns of Parvicapsula minibicornis (Myxozoa) small subunit ribosomal RNA genetic types. Parasitology 138:969-977.
Fujiwara, M., M.S. Mohr, A. Greenberg, J.S. Foott and J.L. Bartholomew. 2011. Effects of myxozoan disease on population dynamics of Pacific salmon. Transactions of the American Fisheries Society 140:1380-1391.
Zielinski, C.M., H.V. Lorz, S.L. Hallett, L. Xue and J.L. Bartholomew. 2011. Comparative susceptibility of Deschutes River (Oregon, USA) Tubifex tubifex populations to Myxobolus cerebralis. Journal of Aquatic Animal Health 23:1-8.
Zhang, Y-A., I. Salinas, J. Li, D. Parra, S. Bjork, S. LePatra, J. Bartholomew and J.O. Sunyer. 2010. IgT, a primitive immunoglobulin class specialized in mucosal immunity. Nature Immunology 11:827-835.
Bjork, S.J. and J.L. Bartholomew. 2010. Invasion of Ceratomyxa shasta (Myzozoa) and comparison of migration to the intestine between susceptible and resistant fish hosts. International Journal for Parasitology, 40:1087-1095.
Bartholomew, J.L. and S.L. Hallett. Myxobolus cerebralis and Ceratomyxa shasta. IN: Fish Parasites: Pathobiology and Protection. P.T.K. Woo and K. Buckmann Eds., CAB International, Wallingford, 2012.
Bartholomew, J.L. Myxobolus cerebralis. IN: Handbook of Global Freshwater Invasive Species. R. Francis, Ed., Earthscan, London. 2012.