West Nile Virus Maps and Statistics

• West Nile virus (WNV) was first found in Minnesota in 2002 and has since become the most commonly reported mosquitoborne disease in the state.
• The highest risk areas for WNV in Minnesota include the western and central portions of the state. Open areas, such as farmland and prairie, provide the best habitat for Culex tarsalis, the primary mosquito vector of the virus.
• Similar to other arboviruses, most WNV cases occur later in the summer (July through September) when infected vector populations are at their highest level.
• In 2018, 63 WNV disease cases were reported in Minnesota, slightly more than the median number of cases per year (49) from 2012 to 2017.
  • 39 (62%) cases were hospitalized and 35 (56%) cases had a severe illness affecting the central nervous system (encephalitis or meningitis), including two fatalities in older adults.
  • 44 (70%) cases were male.
  • Median age was 62 years (range, 21 to 91 years).
  • 21 WNV-positive blood donors who did not have any symptoms of illness were also identified.

Maps and Graphs

• Reported Cases of West Nile virus disease in Minnesota by Year, 2002-2018 (PDF)
  Graph showing the number of reported cases of West Nile virus disease in Minnesota by year.
• High Risk Areas for West Nile Virus Disease in Minnesota (PDF)
  Map of Minnesota showing the average incidence (cases/100,000 population) of cases of West Nile virus disease by county from 2002 through 2018.

Annual Summaries

• Arboviral Disease, 2019
  Minnesota Department of Health Disease Control Newsletter Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2019
  • Arboviral Disease, 2018
  • Arboviral Disease, 2017
  • Arboviral Disease, 2016
  • Arboviral Disease, 2015
  • Arboviral Disease, 2014
  • Arboviral Disease, 2013
  • Arboviral Disease, 2012
  • Arboviral Disease, 2011
  • Arboviral Disease, 2010
  • Arboviral Disease, 2009
  • Arboviral Disease, 2008
  • Arboviral Disease, 2007
  • Arboviral Disease, 2006
  • Arboviral Encephalitis, 2005
  • Arboviral Encephalitis, 2004
  • Arboviral Encephalitis, 2003
  • Arboviral Encephalitis, 2002
  • Arboviral Encephalitis, 2001
  • Arboviral Encephalitis, 2000

Archive of Maps

• 2018 - Minnesota Human West Nile Virus Monitoring (PDF)
• 2017 - Minnesota Human West Nile Virus Monitoring (PDF)
• 2016 - Minnesota Human West Nile Virus Monitoring (PDF)
• 2015 - Minnesota Human West Nile Virus Monitoring (PDF)
• 2014 - Minnesota Human West Nile Virus Monitoring (PDF)
• 2013 - Minnesota Human West Nile Virus Monitoring (PDF)
• 2012 - Minnesota Human West Nile Virus Monitoring (PDF)
• 2011 - Minnesota West Nile Virus Monitoring (PDF)
• 2010 - Minnesota West Nile Virus Monitoring (PDF)
• 2009 - Minnesota West Nile Virus Monitoring (PD)
• 2008 - Minnesota West Nile Virus Monitoring (PDF)
• 2007 - Minnesota West Nile Virus Monitoring (PDF)
• 2006 - Minnesota West Nile Virus Monitoring (PDF)
• 2005 - Minnesota West Nile Virus Monitoring (PDF)
• 2004 - Minnesota West Nile Virus Monitoring (PDF)
• 2003 - Map of counties with positive birds, horses and humans (PDF)
• 2002 - Map of counties with positive birds, horses and humans (PDF)
  • 2002 - Map of counties with positive horses (PDF)

National Statistics

• CDC: West Nile Virus Statistics & Maps
  Centers for Disease Control and Prevention.