July 27, 2006 - (STOCKTON) - (Stockton, CA) — The California Department of Health Services in conjunction with the California Department of Food & Agriculture has informed San Joaquin County that a horse in the Tracy area, zip code 95377, tested positive for West Nile virus (WNV).  This is the first horse in San Joaquin County testing positive for WNV in 2006.  The horse had onset of illness on July 18, 2006.  The horse died or was euthanized on July 26, 2006.  It is not known if the animal had been vaccinated.

Horse owners should be aware of the symptoms of West Nile virus and be on the alert in the event that this disease affects other horses in the area. Signs of West Nile virus in horses include stumbling, staggering, wobbling, weakness, muscle twitching or inability to stand. Horse owners should contact a veterinarian at once if their horse exhibits any of these symptoms. 

The best prevention measure a horse owner can take to protect their horse against WNV is to vaccinate it with one of two vaccines available through a veterinarian or other sources.  In addition to ensuring that horse vaccinations are current, it’s important to reduce a horse's exposure to mosquitoes by taking appropriate prevention measures.  This includes eliminating all sources of standing water that can support mosquito breeding, spraying horses with horse mosquito repellant, keeping horses in a barn at dawn and at dusk (peak mosquito exposure time), turning off barn lights at night, screening barn windows, and using fans to circulate air to reduce mosquitoes reaching horses.

West Nile virus is transmitted to horses and humans through the bite of an infected mosquito.  Mosquitoes become infected with the virus when they feed on infected birds, which transport the virus from place to place. Horses are not contagious to other horses, or to people.  Not every horse exposed to the virus will develop symptoms.  The disease was detected in 19 horses in San Joaquin County in 2005; nine of these horses died. In California, during 2005, there were 456 confirmed cases of equine WNV; 200 horses died or were euthanized.

People can reduce their risk of mosquito-borne diseases by taking these precautions:

• Apply insect repellent containing the active ingredient DEET or Picaridin when outdoors, according to label instructions.
• Avoid spending time outside when mosquitoes are most active, at dawn and dusk, and especially for the first two hours after sunset.
• When outdoors, wear long pants, long-sleeved shirts and other protective clothing.
• Exclude mosquitoes from your home with tight fitting screens on doors and windows.
• Eliminate all sources of standing water on your property that can support mosquito breeding.
• Contact your veterinarian for information on vaccinating equine against WNV.
• Report all dead birds to 1-877-WNV-BIRD (1-877-968-2473) or www.westnile.ca.gov.
• Report significant mosquito infestations to San Joaquin County Mosquito & Vector Control District at 209-982-4675 or 1-800-300-4675.

For 2006 to date there has been one reported West Nile virus positive human case, 25 dead birds, 12 groups of collected mosquitoes, and one sentinel chicken testing positive for West Nile virus in San Joaquin County.

For more information about West Nile virus:

• San Joaquin County recorded information line:  (209) 469-8200
• San Joaquin County WNV website: http://www.sjmosquito.org
• Statewide information can also be obtained by calling 1-877-WNV-BIRD (1-877-968-2473) or on line at www.westnile.ca.gov.
• California Department of Food and Agriculture website: www.cdfa.ca.gov.

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