Picture of John Harding

John Harding Professor, Department of Large Animal Clinical Sciences

Research Area(s)

  • Emerging and re-emerging diseases of pigs

Academic Credentials

  • DVM, Ontario Veterinary College, 1988.
  • MSc, University of Minnesota, 1997.
  • Diplomate, American Board of Veterinary Practitioners (ABVP) — Swine Health Management, 2008.

Research Interests

The theme of Dr. Harding's research is emerging and re-emerging diseases of pigs. Earlier in his career, he co-discovered porcine circovirus type 2, and characterized its impact and epidemiology in affected farms. More recently, his research has focused on other novel diseases and syndromes, most notably "Brachyspira hampsonii" colitis and periweaning failure-to-thrive syndrome (PFTS).

In addition, his current research aims to understand mechanisms associated with severity of reproductive PRRS, as well investigating prenatal immunologic programming associated with intrauterine growth retardation. Dr. Harding was awarded the Pfizer Animal Health Award for Research Excellence in 2010.

Publications

  • Bai, X., Putz, A.M., Wang, Z., Fortin, F., Harding, J.C.S., Dyck, M.K., Dekkers, J.C.M., Field, C.J., Plastow, G.S., PigGen Canada. 2020.  Exploring phenotypes for disease resilience in pigs using complete blood count data from a natural disease challenge model.  Frontiers in Genetics, 11: 216.  https://www.doi.org/10.3389/fgene.2020.00216 

  • Cheng, J., Putz, A.M., Harding, J.C.S., Dyck, M.K., Fortin, F., Plastow, G.S., Canada, P., Dekkers, J.C.M.  2020.  Genetic analysis of disease resilience in wean-to-finish pigs from a natural disease challenge model.  Journal of Animal Science, 98(8): skaa244.  https://www.doi.org/10.1093/jas/skaa244

  • Cheng, J., Putz, A.M., Harding, J.C.S., Dyck, M.K., Fortin, F., Plastow, G.S., Canada, P., Dekkers, J.C.M.  2020.  Genetic analysis of disease resilience in wean-to-finish pigs from a natural disease challenge model.  Journal of Animal Science, 98(8): skaa244.  https://www.doi.org/10.1093/jas/skaa244

  • Costa, M.O., Fouhse, J., Silva, A.P.P., Willing, B., Harding, J.C.S.  2020.  Putting the microbiota to work: Epigenetic effects of early life antibiotic treatment are associated with immune-related pathways and reduced epithelial necrosis following Salmonella Typhimurium challenge in vitro.  PLoS ONE, 15(4): e0231942.  https://www.doi.org/10.1371/journal.pone.0231942

  • Costa, M.O., Harding, J.C.S.  2020.  Swine dysentery disease mechanism: Brachyspira hampsonii impairs the colonic immune and epithelial repair responses to induce lesions.  Microbial Pathogenesis, 148: 104470.  https://www.doi.org/10.1016/j.micpath.2020.104470

  • Enns, C.B., Keith, B.A., Challa, N., Harding, J.C.S., Loewen, M.E.  2020.  Impairment of electroneutral Na+transport and associated downregulation of NHE3 contributes to the development of diarrhea following in vivo challenge with Brachyspira spp.  American Journal of Physiology - Gastrointestinal and Liver Physiology, 318(2): G288-G297.  https://www.doi.org/10.1152/AJPGI.00011.2019

  • Malgarin, C.M., MacPhee, D.J., Harding, J.C.S.  2020.  Fetal metabolomic alterations following porcine reproductive and respiratory syndrome virus infection.  Frontiers in Molecular Biosciences, 7: 559688.  https://www.doi.org/10.3389/fmolb.2020.559688

  • Pasternak, J.A., MacPhee, D.J., Harding, J.C.S.  2020.  Fetal cytokine response to porcine reproductive and respiratory syndrome virus-2 infection.  Cytokine, 126: 154883.  https://www.doi.org/10.1016/j.cyto.2019.154883

  • Pasternak, J.A., MacPhee, D.J., Harding, J.C.S.  2020.  Maternal and fetal thyroid dysfunction following porcine reproductive and respiratory syndrome virus2 infection.  Veterinary Research, 51(1): 47.  https://www.doi.org/10.1186/s13567-020-00772-2

  • Perri, A.M., Poljak, Z., Dewey, C., Harding, J.C.S., O'Sullivan, T.L.  2020.  A descriptive study of on-farm biosecurity and management practices during the incursion of porcine epidemic diarrhea into Canadian swine herds, 2014.  Journal of Veterinary Science, 21(2): e25.  https://www.doi.org/10.4142/JVS.2020.21.E25

  • Sanglard, L.P., Mote, B.E., Willson, P., Harding, J.C.S., Plastow, G.S., Dekkers, J.C.M., Serão, N.V.L.  2020.  Genomic analysis of IgG antibody response to common pathogens in commercial sows in health-challenged herds.  Frontiers in Genetics, 11: 593804.  https://www.doi.org/10.3389/fgene.2020.593804

  • Van Goor, A., Pasternak, A., Walker, K., Hong, L., Malgarin, C., MacPhee, D.J., Harding, J.C.S., Lunney, J.K.  2020.  Differential responses in placenta and fetal thymus at 12 days post infection elucidate mechanisms of viral level and fetal compromise following PRRSV2 infection.  BMC Genomics, 21(1): 763.  https://www.doi.org/10.1186/s12864-020-07154-0

  • Costa, M.O., Ek, C.E., Patterson, M.H., Nosach, R., Detmer, S.E., Fernando, C., PaulMcKenzie, G., van Ravenstein, S., Enns, C.B., Loewen, M.E., Hill, J.E., Harding, J.C.S.  2019.  Subclinical colitis associated with moderately hemolytic Brachyspira strains.  Journal of Swine Health and Production, 27(4): 196-209.

  • Enns, C.B., Harding, J.C.S., Loewen, M.E.  2019.  Decreased electrogenic anionic secretory response in the porcine colon following in vivo challenge with Brachyspira spp. supports an altered mucin environment.  American Journal of Physiology - Gastrointestinal and Liver Physiology, 316(4): G495-G508.  https://www.doi.org/10.1152/ajpgi.00348.2018

  • Hill, J.E., Detmer, S.E., Fernando, C., Derbawka, S.A., Nosach, R., Harding, J.C.S.  2019.  Retrospective detection of Brachyspira hampsonii in archived colitis cases from western Canadian swine.  Transboundary and Emerging Diseases, 66(1): 381-388.  https://www.doi.org/10.1111/tbed.13032

  • Malgarin, C.M., Nosach, R., Novakovic, P., Suleman, M., Ladinig, A., Detmer, S.E., MacPhee, D.J., Harding, J.C.S.  2019.  Classification of fetal resilience to porcine reproductive and respiratory syndrome (PRRS) based on temporal viral load in late gestation maternal tissues and fetuses.  Virus Research, 260: 151-162.  https://www.doi.org/10.1016/j.virusres.2018.12.002

  • Pasternak, J.A., MacPhee, D.J., Harding, J.C.S.  2019.  Development and application of a porcine specific ELISA for the quantification of soluble CD163.  Veterinary Immunology and Immunopathology, 210: 60-67.  https://www.doi.org/10.1016/j.vetimm.2019.03.011

  • Perri, A.M., Poljak, Z., Dewey, C., Harding, J.C.S., O'Sullivan, T.L.  2019.  Factors associated with time to elimination of porcine epidemic diarrhea virus in individual Ontario swine herds based on surveillance data.  Frontiers in Veterinary Science, 6: 139.  https://www.doi.org/10.3389/fvets.2019.00139

  • Perri, A.M., Poljak, Z., Dewey, C., Harding, J.C.S., O'Sullivan, T.L.  2019.  Network analyses using case-control data to describe and characterize the initial 2014 incursion of porcine epidemic diarrhea (PED) in Canadian swine herds.  Preventive Veterinary Medicine, 162: 18-28.  https://www.doi.org/10.1016/j.prevetmed.2018.11.001

  • Putz, A.M., Harding, J.C.S., Dyck, M.K., Fortin, F., Plastow, G.S., Dekkers, J.C.M.  2019.  Novel resilience phenotypes using feed intake data from a natural disease challenge model in wean-to-finish pigs.  Frontiers in Genetics, 10: 660.  https://www.doi.org/10.3389/fgene.2018.00660

  • Suleman, M., Malgarin, C.M., Detmer, S.E., Harding, J.C.S., MacPhee, D.J.  2019.  The porcine trophoblast cell line PTr2 is susceptible to porcine reproductive and respiratory syndrome virus-2 infection.  Placenta, 88: 44-51.  https://www.doi.org/10.1016/j.placenta.2019.10.004

  • Bertolini, F., Yang, T., Huang, Y., Harding, J.C.S., Plastow, G.S., Rothschild, M.F.  2018.  Genomic investigation of porcine periweaning failure to thrive syndrome (PFTS).  Veterinary Record, 183(3).  https://www.doi.org/10.1136/vr.104825

  • Costa, M.O., Hill, J.E., Dame, M.K., Harding, J.C.S.  2018.  In vitro porcine colon culture.  Methods in Molecular Biology, 1817: 185-195.  https://www.doi.org/10.1007/978-1-4939-8600-2_18

  • Johnson, L.A., Fernando, C., Harding, J.C.S., Hill, J.E.  2018.  Characterization of Brachyspira communities from clinical cases of swine mucohaemorrhagic diarrhea through deep sequencing of the NADH oxidase (nox) gene.  Veterinary Microbiology, 214: 81-88.  https://www.doi.org/10.1016/j.vetmic.2017.12.012

  • Novakovic, P., Detmer, S.E., Suleman, M., Malgarin, C.M., MacPhee, D.J., Harding, J.C.S.  2018.  Histologic changes associated with placental separation in gilts infected with porcine reproductive and respiratory syndrome virus.  Veterinary Pathology, 55(4): 521-530.  https://www.doi.org/10.1177/0300985818765067

  • Perez, J.B.D.S., Fernando, C., Nosach, R.V., Huang, Y., Harding, J.C.S., Hill, J.E.  2018.  In vitro attenuation of a virulent swine isolate of Brachyspira hampsonii.  Pathogens and Disease, 76(1): ftx116.  https://www.doi.org/10.1093/femspd/ftx116

  • Perri, A.M., Poljak, Z., Dewey, C., Harding, J.C.S., O'Sullivan, T.L.  2018.  An epidemiological investigation of the early phase of the porcine epidemic diarrhea (PED) outbreak in Canadian swine herds in 2014: A case-control study.  Preventive Veterinary Medicine, 150: 101-109.  https://www.doi.org/10.1016/j.prevetmed.2017.12.009

  • Suleman, M., Novakovic, P., Malgarin, C.M., Detmer, S.E., Harding, J.C.S., MacPhee, D.J.  2018.  Spatiotemporal immunofluorescent evaluation of porcine reproductive and respiratory syndrome virus transmission across the maternal-fetal interface.  Pathogens and Disease, 76(5).  https://www.doi.org/10.1093/femspd/fty060

  • Verhoef, J.N.C., Allen, A.L., Harding, J.C.S., Al-Dissi, A.N.  2018.  Metallothionein expression in horses with chronic liver disease and its correlation with Ki-67 immunoreactivity.  Veterinary Pathology, 55(5): 703-710.  https://www.doi.org/10.1177/0300985818777802

  • Bertolini, F., Harding, J.C.S., Mote, B., Ladinig, A., Plastow, G.S., Rothschild, M.F.  2017.  Genomic investigation of piglet resilience following porcine epidemic diarrhea outbreaks.  Animal Genetics, 48(2): 228-232.  https://www.doi.org/10.1111/age.12522

  • Costa, M.O., Fernando, C., Nosach, R., Harding, J.C.S., Hill, J.E.  2017.  Infection of porcine colon explants with "Brachyspira hampsonii" leads to increased epithelial necrosis and catarrhal exudate.  Pathogens and Disease, 75(3).  https://www.doi.org/10.1093/femspd/ftx032

  • Ek, C.E., Nosach, R., Fernando, C., Huang, Y., Perez, J.B.D.S., Costa, M.O., Ekanayake, S., Hill, J.E., Harding, J.C.S.  2017.  An optimized swine dysentery murine model to characterize shedding and clinical disease associated with "Brachyspira hampsonii" infection.  BMC Veterinary Research, 13(1): 261. https://www.doi.org/10.1186/s12917-017-1166-5 

  • Harding, J.C.S., Ladinig, A., Novakovic, P., Detmer, S.E., Wilkinson, J.M., Yang, T., Lunney, J.K., Plastow, G.S.  2017.  Novel insights into host responses and reproductive pathophysiology of porcine reproductive and respiratory syndrome caused by PRRSV-2.  Veterinary Microbiology, 209: 114-123.  https://www.doi.org/10.1016/j.vetmic.2017.02.019

  • Novakovic, P., Harding, J.C.S., Al-Dissi, A.N., Detmer, S.E.  2017.  Type 2 porcine reproductive and respiratory syndrome virus infection increases apoptosis at the maternal-fetal interface in late gestation pregnant gilts.  PLoS ONE, 12(3): e0173360.  https://www.doi.org/10.1371/journal.pone.0173360

  • Perri, A.M., O'Sullivan, T.L., Harding, J.C.S., Wood, R.D., Friendship, R.M.  2017.  Hematology and biochemistry reference intervals for Ontario commercial nursing pigs close to the time of weaning.  Canadian Veterinary Journal, 58(4): 371-376.

  • Costa, M.O., Harding, J.C.S., Hill, J.E.  2016.  Development and evaluation of a porcine in vitro colon organ culture technique.  In Vitro Cellular and Developmental Biology – Animal, 52(9): 942-952.  https://www.doi.org/10.1007/s11626-016-0060-y

  • Novakovic, P., Harding, J.C.S., Al-Dissi, A.N., Ladinig, A., Detmer, S.E.  2016.  Pathologic evaluation of type 2 porcine reproductive and respiratory syndrome virus infection at the maternal-fetal interface of late gestation pregnant gilts.  PLoS ONE, 11(3): e0151198.  https://www.doi.org/10.1371/journal.pone.0151198

  • Novakovic, P., Harding, J.C.S., Ladinig, A., Al-Dissi, A.N., MacPhee, D.J., Detmer, S.E.  2016.  Relationships of CD163 and CD169 positive cell numbers in the endometrium and fetal placenta with type 2 PRRSV RNA concentration in fetal thymus.  Veterinary Research, 47(1): 76.  https://www.doi.org/10.1186/s13567-016-0364-7

  • Perri, A.M., Friendship, R.M., Harding, J.C.S., O'Sullivan, T.L.  2016.  An investigation of iron deficiency and anemia in piglets and the effect of iron status at weaning on post-weaning performance.  Journal of Swine Health and Production, 24(1): 10-20.

  • Perri, A.M., O'Sullivan, T.L., Harding, J.C.S., Friendship, R.M.  2016.  The use of serum beta-hydroxybutyrate to determine whether nursery pigs selected on the basis of clinical signs are anorexic.  Canadian Veterinary Journal, 57(11): 1143-1148.

  • Serão, N.V.L., Kemp, R.A., Mote, B.E., Willson, P., Harding, J.C.S., Bishop, S.C., Plastow, G.S., Dekkers, J.C.M.  2016.  Genetic and genomic basis of antibody response to porcine reproductive and respiratory syndrome (PRRS) in gilts and sows.  Genetics Selection Evolution, 48(1): 51.  https://www.doi.org/10.1186/s12711-016-0230-0

  • Wilkinson, J.M., Bao, H., Ladinig, A., Hong, L., Stothard, P., Lunney, J.K., Plastow, G.S., Harding, J.C.S.  2016.  Genome-wide analysis of the transcriptional response to porcine reproductive and respiratory syndrome virus infection at the maternal/fetal interface and in the fetus.  BMC Genomics, 17(1): 383.  https://www.doi.org/10.1186/s12864-016-2720-4

  • Wilkinson, J.M., Ladinig, A., Bao, H., Kommadath, A., Stothard, P., Lunney, J.K., Harding, J.C.S., Plastow, G.S.  2016.  Differences in whole blood gene expression associated with infection time-course and extent of fetal mortality in a reproductive model of type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection.  PLoS ONE, 11(4): e0153615.  https://www.doi.org/10.1371/journal.pone.0153615

  • Yang, T., Wilkinson, J., Wang, Z., Ladinig, A., Harding, J., Plastow, G.  2016.  A genome-wide association study of fetal response to type 2 porcine reproductive and respiratory syndrome virus challenge.  Scientific Reports, 6: 20305.  https://www.doi.org/10.1038/srep20305