MSMVCD Confirms First West Nile Virus Horse Case For 2014

Release date: 
Aug 26

Cotati, CA-The Marin/Sonoma Mosquito and Vector Control District (MSMVCD) received confirmation that a horse residing near Calistoga has tested positive for West Nile virus. This is the first confirmed West Nile virus infection contracted by a horse this year in Marin and Sonoma counties. The horse was not vaccinated against the virus; however, it is alive and recovering from the infection.

Horse owners should consult a veterinarian if their horse exhibits any of the following signs:

  • Fever
  • Incoordination, especially in rear limbs, causing stumbling and falling
  • Generalized weakness, muscle twitching, seizures or coma
  • Drooping lips and lip smacking, head drooping, grinding teeth
  • Hypersensitivity to touch or sound  
  • Recumbency (inability to rise)

Simple ways to protect your horses against WNV:

  • Maintain current vaccination status, including WNV.
  • Place fans inside barns and stalls to maintain air movement, as mosquitoes cannot fly well in wind.
  • Stock water troughs, ponds or other permanent water features with mosquitofish. The fish are free and can be delivered or picked up at the District office.
  • Use equine-approved mosquito repellents and/or protective horse gear such as fly sheets, masks, and leg wraps.
  • Check septic tank lids to ensure a tight seal and repair any visible cracks.
  • Screen septic tank vent pipes using a fine mesh screen.
  • Eliminate standing water in rain barrels, old tires, buckets, kiddie pools or any other item that can hold water for more than 72 hours. 
  • Report mosquito problems, neglected swimming pools, or any area that could be producing mosquitoes at or 1-800-231-3236.


2014 West Nile virus activity:

Marin County: 3 dead birds and 3 mosquito samples have tested positive for West Nile virus to date.

Sonoma County: 13 dead birds, 1 equine case, 1 sentinel chicken and 4 mosquito samples have tested positive for West Nile virus to date.