Two Montana Horses Infected With West Nile


The following is a press release from the Montana Department of Livestock:

Montana’s state veterinarian is advising equine owners to consult their veterinarians about West Nile vaccination after two horses turned up positive for the disease.

“We have two positives and know there are positive mosquito pools, so it’s prudent for equine owners to consider vaccination,” said Dr. Marty Zaluski, Montana Department of Livestock.

Equine owners should also be familiar with clinical signs of the disease, he said, which are variable and may include:

  • Loss of appetite and depression;
  • Progressing lameness and/or weakness/paralysis of limbs;
  • Loss of coordination;
  • Muzzle twitching;
  • Impaired vision;
  • Convulsions;
  • Inability to swallow;
  • Behavioral changes;
  • Coma. 

WNV mimics other serious neurological diseases like sleeping sickness, equine encephalitis and rabies, and should be immediately reported so that a licensed veterinarian can make a diagnosis.

Although most equines recover from the disease, WNV kills about a third of the horses infected. There is no specific treatment for WNV in equines, although supportive care consistent with standard veterinary practice for animals with a viral infection is recommended

Vaccination is an effective and inexpensive way to prevent the disease, Zaluksi said, and is recommended as a core vaccine by the American Association of Equine Practitioners. Consult your local veterinarian to develop a preventive health plan that includes WNV vaccination.

WNV was first found on the east coast of the U.S. in 1999. Since then, the disease has spread westward, arriving in Montana in 2002. WNV knows no boundaries within the state, and has been found statewide. The two infected horses, located in Carbon and Powder River counties, are the state’s first since 2009, when 14 positives were reported.

Earlier this year, researchers at Montana State University expected the worst when unusually high numbers of mosquitoes were found around the state. Greg Johnson, veterinary entomologist at MSU’s Department of Animal & Range Sciences, says mosquito numbers have dropped the past couple of weeks but that concerns remain.

“Mosquito season can last through September and even into October, so we’re not out of the woods yet,” Johnson said. 

Effective mosquito control helps decrease the potential for spreading the disease. Watering troughs should be cleaned thoroughly and regularly, and standing water where mosquitoes breed should be managed if possible. A variety of water treatments that kill fly and mosquito larvae but are nontoxic to animals are commercially available.

Montana has also had one case of WNV in humans this year.

An informational FAQ on WNV in horses is available from the Centers for Disease Control, as is additional information on human aspects of the disease. The state Department of Health & Human Services also has recommendations for limiting human exposure to WNV.

Source:  Montana Department of Livestock

Posted by Haylie Shipp


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