Zvonimir Poljak

Zvonimir Poljak

Associate Professor

DVM (Croatia), MSc, PhD (Guelph)


My research interests include studying the spread of infectious diseases in swine. Swine populations of interest include animals within herds, and herds within areas. To study spread, I use a variety of quantitative methods.

Research Interests

  • Mapping the occurrence of PRRS virus genotypes in Ontario
  • Assessing the frequency of direct and indirect contacts in Ontario swine herds and other aspects of pig movement
  • Within-area spread of influenza
  • Within-herd spread of respiratory pathogens in growing pigs

Current Graduate Students

  • Barr Hadar - PhD
  • Kaushalya Kuruppu - PhD
  • Dylan Melmer - PhD
  • Famke Alberts - MSc


In the past, I contributed to teaching Epidemiology I (POPM*6200), and Geographical Epidemiology (POPM*6950), Currently, I co-teach a graduate course in Swine Health Management (POPM*6700).

Selected Publications

  • Poljak Z, Dewey CE, Martin SW, Christensen J, Carman S, Friendship RM. Spatial clustering of swine influenza in Ontario on the basis of herd-level disease status with different misclassification errors. Preventive Veterinary Medicine. 2007; 81:236-249.
  • Poljak Z, Dewey CE, Friendship RM, Martin SW, Christensen J. Multilevel analysis of risk factors for Salmonella shedding in Ontario finishing pigs. Epidemiology and Infection. 2007; 1-13.
  • Poljak Z, Friendship RM , Carman S, McNab WB, Dewey CE. Investigation of exposure to swine influenza viruses in Ontario (Canada) finisher herds in 2004 and 2005. Preventive Veterinary Medicine. 2008; 83:24-40.
  • Poljak Z, Dewey C, Friendship R, Martin S, Christensen J, Ojkic D, Wu J, Chow E. Pig and herd level prevalence of Toxoplasma gondii in Ontario finisher pigs in 2001, 2003, and 2004. Canadian Journal of Veterinary Research. Accepted.
  • Poljak Z, Dewey C, Martin S, Christensen J, Carman S, Friendship R. Prevalence and risk factors for influenza in southern Ontario swine farms in 2001 and 2003. Canadian Journal of Veterinary Research. In press.
  • Labrovic A, Poljak Z, ҆eparovic S, Jukic B, Lukman D, ListeŇ° E, Bosnic S. Spatial distribution of bluetongue in cattle in southern Croatia in the last quarter of 2002. Veterinaria Italiana. 2004;40:217-220.