West Nile Virus

Additional information
WNV cases in 2012
2012 West Nile Virus Map

West Nile Virus (WNV) is a viral disease that can affect horses. Birds serve as the primary host for the virus, which is spread by mosquitoes to other birds and a wide range of susceptible animals including horses and humans.

WNV can cause encephalitis, an inflammation of the brain and spinal cord. Infected horses may or may not show neurological symptoms, and many recover completely from the diseases.

WNV was first identified in the United States in 1999. WNV is now endemic to the entire continental United States and worldwide. Most cases of WNV in Minnesota occur when mosquitoes are most active, usually throughout the summer months into mid-September.

You can help prevent WNV in horses by taking the following steps:

  • Vaccinate
  • Eliminate "mosquito zones" by mowing long grass, draining stagnant water puddles, and removing items such as old tires and tin cans that can serve as breeding grounds for mosquitoes.
  • Change water in drinking troughs at least once a week to prevent mosquito breeding.
  • Use mosquito repellents and place screens in stables.

Any case of WNV in horses must be reported to the Board by calling 651-201-6804.