William Ryan Easterday


Avdeling for forskning, innovasjon og internasjonalisering
Seksjon for Forskning og innovasjon
Campus Vestfold ()
Ryan has been conducting broad research on bacterial pathogens since 2002 in the fields of ecology, evolution, molecular genetics, genomics, pathology and immunology. He started doing field work on plague (Yersinia pestis, norsk: pest) in the four-corners region while finishing his bachelor in zoology at Northern Arizona University. He worked in the laboratory developing high-throughput DNA extraction techniques for vectors and subsequent screening and genotyping techniques for various pathogens. He also did extensive work on the Amerithrax case (anthrax letters) with the FBI, developing and applying DNA fingerprinting techniques for forensic applications. Since then he was working in researcher and advisor roles, mostly based out of the Centre for Ecological and Evolutionary Synthesis at the University of Oslo, in the USA, Namibia, China, Georgia and Norway from 2009-2019. He started here in the Research and Innovation section at USN in 2019.









Nov. 2011 Doctor Philos, Biology

Department of Biosciences, Faculty of Mathematics & Natural Sciences, University of Oslo, Norway

May 2003 Bachelor of Science, Zoology, pre-health professional                                                                                         

Dept. of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA



1. W. Ryan Easterday, Wendy C. Turner, Matthew Van Ert, José Miguel Ponciano, Ted Hadfield, Karoun Bagamian, Jason K. Blackburn & Nils Chr. Stenseth. Coalescence modeling of intra-infection Bacillus anthracis populations allows non-invasive estimation of anthrax infection parameters in wild populations. PNAS cover article. issue 8, Feb 25, 2020.

2. Pernille Nilsson, Monica H Solbakken, Boris V Schmid, Russell JS Orr, Ruichen Lv, Yujun Cui, Yajun Song, Yujiang Zhang, Nils Chr Stenseth, Ruifu Yang, Kjetill S Jakobsen, W. Ryan Easterday & Sissel Jentoft. The genome of the plague-resistant great gerbil reveals species-specific duplication of an MHCII gene. BioRx. 2018. Genome Biology and Evolution. 2020.

3. Yujun Cui, Boris Schmid, Hanli Cao, Xiang Dai, Zongmin Du, W. Ryan Easterday, Haihong Fang, Chenyi Guo, Shanqian Huang, Wanbing Liu, Zhizhen Qi, Yajun Song, Huaiyu Tian, Min Wang, Yarong Wu, Bing Xu, Chao Yang, Jing Yang, Xianwei Yang, Qingwen Zhang, Kjetill Jakobsen, Yujiang Zhang, Nils Stenseth, and Ruifu Yang. Evolutionary selection of biofilm-mediated extended phenotypes in Yersinia pestis in response to a changing environment. Nature Communications. 2020.

4. SA Bruce, NJ Schiraldi, PL Kamath, W. Ryan Easterday, WC Turner. A classification framework for Bacillus anthracis defined by global genomic structure. Evolution Applications. 2019.

5. Pernille Nilsson, Shair Gurbanov and W. Ryan Easterday. Rapid, specific detection of Yersinia pestis using furMAMA. BioRx. 2018.

6. Atle Mysterud, Vetle Malmer Stigum, Ingrid Vikingsdal Seland, Anders Herland, W.Ryan Easterday, Solveig Jore, Olav Østerås, and Hildegunn Viljugrein. Spatial variation in tick-borne diseases at the northern distribution range of Europe. Parasites & Vectors. 2018.

7. Colin J. Carlson, Wayne Getz, Kyrre Kausrud, Carrie Cizauskas, Jason Blackburn, Fausto A Bustos Carrillo, Rita Colwell, W. Ryan Easterday, Holly Ganz, Pauline Kamath, Ole Andreas Okstad, Wendy Turner, Anne-Brit Kolsto and Nils C. Stenseth. Spores and soil from six sides: interdisciplinarity and the environmental biology of anthrax (Bacillus anthracis). Biological Reviews. 2018.

8. Karoline Valseth, Camilla L. Nesbø, W. Ryan Easterday, Wendy C. Turner, Jaran S. Olsen, Nils Chr. Stenseth and Thomas H. A. Haverkamp. Temporal dynamics in microbial soil communities at anthrax carcass sites. BMC Microbiology. 2017.

9. Karoline Valseth, Camilla L. Nesbø, W. Ryan Easterday, Wendy C. Turner, Jaran S. Olsen, Nils Chr. Stenseth and Thomas H. A. Haverkamp. Draft genomes of two Bacillus anthracis strains from Etosha National park, Namibia. ASM Genome Announcements. 2016.

10. Wendy Turner, Kyrre Kausrud, Wolfgang Beyer, W Ryan Easterday, Zoe Barandongo, Elisabeth Blaschke, Claudine Cloete, Judith Lazak, Matthew N Van Ert, Holly Ganz, Peter Turnbull, Nils Chr Stenseth, and Wayne Getz. Lethal exposure: An integrated approach to pathogen transmission via environmental reservoirs. Scientific Reports. 2016.

11. Atle Mysterud, W. Ryan Easterday, Vetle Malmer Stigum, Anders Bjørnsgaard Aas, Erlin Meisingset & Hildegunn Viljugrein. Contrasting limitation of Lyme disease across ecosystems. Nature Communications. 2016.

12. Boris V. Schmid, Ulf Büntgen, W. Ryan Easterday, Christian Ginzler, Lars Walløe, Barbara Bramanti, Nils Chr. Stenseth. Climate-driven introduction of the Black Death and successive plague reintroductions into Europe. PNAS. 2015. 99th percentile

13. Atle Mysterud, W. Ryan Easterday, Lars Qviller, Hildegunn Viljugrein, and Bjørnar Ytrehus. Spatial and seasonal variation in the prevalence of Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato in questing Ixodes ricinus ticks in Norway. Parasites and Vectors. 2013.

14. W. Ryan Easterday, Kyrre L. Kausrud, Bastiaan Star, Lise Heier, Bradd J. Haley, Vladimir Ageyev,  Rita R. Colwell & Nils Chr. Stenseth. An additional step in the transmission of Yersinia pestis? ISME. 2012.

15. Aikembayev, A. , Lukhnova L. , Temiraliyeva G. , Meka-Mechenko T. , Pazylov Y. , Zakaryan S., Denissov J., Easterday W.R. , Van Ert, M.N. , Keim, P. , Francesconi, S.C. , Blackburn J.K. , and Martin Hugh-Jones, Hadfield, T.L. Historical Distribution and Molecular Diversity of Bacillus anthracis in Kazakhstan. Emerging Infectious Diseases. 2010.

16. Tatum S Simonson, Richard T Okinaka, Bingxiang Wang, W Ryan Easterday, Lynn Huynh, Jana M U'Ren, Meghan Dukerich, Shaylan R Zanecki, Leo J Kenefic, Jodi Beaudry, James M Schupp, Talima Pearson, David M Wagner, Alex Hoffmaster, Jacques Ravel and Paul Keim. Bacillus anthracis in China and its relationship to worldwide lineages. BMC Microbiology. 2009.

17. Van Ert MN, Easterday WR, Huynh LY, Okinaka RT, Hugh-Jones ME, Ravel J, Zanecki SR, Pearson T, Simonson TS, U'ren JM, Kachur SM, Leadem-Dougherty RR, Rhoton SD, Zinser G, Farlow J, Coker PR, Smith KL, Wang B, Kenefic LJ, Fraser-Liggett CM, Wagner DM, Keim P. Global Genetic Population Structure of Bacillus anthracis. PLoS ONE. 2007 May.

18. Van Ert MN, W. Ryan Easterday, Tatum S. Simonson, Jana M. U’Ren, Talima Pearson, Leo J. Kenefic, Joseph D. Busch, Lynn Y. Huynh, Megan Dukerich, Carla B. Trim, Jodi Beaudry, Amy Welty-Bernard, Timothy Read, Claire M. Fraser, Jacques Ravel, and Paul Keim. Strain-Specific Single-Nucleotide Polymorphism Assays for the Bacillus anthracis Ames Strain. Journal of Clinical Microbiology. 2007. 

 19. U'Ren JM, Van Ert MN, Schupp JM, Easterday WR, Simonson TS, Okinaka RT, Pearson T, Keim P. Use of a real-time PCR TaqMan assay for rapid identification and differentiation of Burkholderia pseudomallei and Burkholderia mallei. Journal of Clinical Microbiology. 2006.

 20. W. Ryan Easterday, Matthew Van Ert, Shaylan Zanecki and Paul Keim. Specific detection of Bacillus anthracis using a TaqMan® mismatch amplification mutation assay (TaqMAMA). Biotechniques. 2005.

21. W. Ryan Easterday, Matthew N. Van Ert, Tatum S. Simonson, David M. Wagner, Leo J. Kenefic, Christopher J. Allender, and Paul Keim. Specific identification of Bacillus anthracis using SNPs in the plcR gene. Journal of Clinical Microbiology. 2005.

22. Mark Achtman, Giovanna Morelli, Peixuan Zhu, Thierry Wirth, Ines Diehl, Barica Kusecek, Amy J. Vogler, David M. Wagner, Christopher J. Allender, W. Ryan Easterday, Viviane Chenal-Francisque, Patricia Worsham, Nicholas R. Thomson, Julian Parkhill, Luther E. Lindler, Elisabeth Carniel, and Paul Keim. Microevolution and history of the plague bacillus, Yersinia pestis. PNAS. 2004. Top 5%

23. Allender, C.J., W. R. Easterday, M.N. Van Ert, D.M. Wagner, and P. Keim. 2004. High-throughput extraction of arthropod vector and pathogen DNA using bead milling. BioTechniques. 2004.