Old Dominion University
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College of Sciences

Department of Biological Sciences

Holly Gaff, PhD

Assistant Professor, VMASC-Affiliated Faculty Member

Research Interests

Mathematical modeling and simulation of infectious diseases; spatial heterogeneity; GIS; tick-borne diseases; nosocomial infections; ecology of infectious diseases.


  • Ph.D., University of Tennessee, Knoxville, Mathematics with a Concentration in Mathematical Ecology, 1999
  • B.S. Taylor University, Mathematics/Environmental Science, 1993

Professional Experience

  • Assistant Professor, School of Community and Environmental Health and Virginia Modeling, Analysis and Simulation Center, Old Dominion University, August 2007-present
  • Assistant Professor, Department of Epidemiology and Preventive Medicine, University of Maryland, Baltimore, Maryland, August 2004-July 2007
  • Research Scientist, Dynamics Technology, Inc., Arlington, Virginia, April 2003-July 2004
  • Postdoctoral Research Associate, The Institute for Environmental Modeling, University of Tennessee, Knoxville, February 2002-April 2003
  • Application Consultant, Onward, Inc., Mountain View, California, April 2001-January 2002
  • Postdoctoral Fellow, Division of Ecosystem Sciences, ESPM, University of California, Berkeley, March 2000-March 2001
  • Postdoctoral Fellow, Department of Medicine, University of California, San Francisco, August 1999-March 2000

Selected Publications

  1. Gaff, H.  and L. J. Gross, Analysis of a tick-borne disease model with varying population sizes in various habitats, Bulletin of Mathematical Biology, (2007) 69:265-288.
  2. Gaff, H., H. R., Joshi, and S. Lenhart, Optimal harvesting during an invasion of a sublethal plant pathogen, Environment and Development Economics, (2007) 12: 673-686.
  3. Gaff, H., D. Hartley and N. Leahy, An epidemiological model for Rift Valley fever virus, Electronic Journal of Differential Equations, (2007) Vol 2007(115):1-12.
  4. Joshi, H. R., S. Lenhart, H. Lou, and H. Gaff, Harvesting Control in an integrodifference population model with concave growth term, Nonlinear Analysis: Hybrid Systems, (2007) 1: 417-429.
  5. Furuno JP, Harris AD, Wright MO, Hartley DM, McGregor, JC, Gaff HD, Hebden JN,  Standiford HC, Perencevich EN; Utility of active surveillance culturing for methicillin-resistant Staphylococcus aureus upon intensive care unit discharge. Infection Control and Hospital Epidemiology, (2007) 28:666-670.
  6. Joshi, H. R., S. Lenhart, and H. Gaff, Optimal Harvesting in an Integro-difference Population Model, Optimal Control Applications and Methods (2006) 27:61-75.

Current and Past Research Grants

  1. Principal Investigator, NIH K25 Award KAI067791A, Spatially-explicit mathematical model of human monocytic ehrlichiosis, 06/01/07 - 03/31/10
  2. Co-Investigator, Johns Hopkins University/CDC, T. Perl (PI), Bring Value Through BioSense - a Performance Based Approach, 10/01/06-09/30/09
  3. Co-Investigator, Georgetown University Argus Project, D. M. Hartley (PI), $100,000, 09/01/06-05/31/07
  4. Co-Investigator, CDC, A. Harris (PI),  New Nosocomial Interventions to Decrease Antimicrobial Resistance $573,446, 9/30/06 - 05/31/07
  5. Co-Investigator, Office of Homeland Security, D. M. Hartley (PI), Modeling of Rift Valley Fever for Agricultural Bioterrorism Defense, $390,010, 05/01/04-04/30/07

Contact information

Holly Gaff
Assistant Professor
Biology, College of Sciences
Virginia Modeling, Analysis and Simulation Center
Old Dominion University