The Utah Department of Agriculture has recently confirmed that three horses have tested positive for West Nile Virus in horses. Two of these cases were reported in Box Elder County, while another case was identified in Utah County.

This discovery serves as an important reminder for horse owners across the state—and the entire country—that mosquito-borne diseases like West Nile Virus (WNV) remain a seasonal health risk for equines.

Understanding West Nile Virus in Horses

West Nile Virus in horses is transmitted through mosquito bites. Mosquitoes become infected after feeding on birds carrying the virus and can then pass it on to horses or humans. While not every infected horse will show obvious symptoms, those that do can suffer from mild to severe illness.

Some horses may only develop a slight fever or loss of appetite, while others may face more serious neurological problems. In severe cases, horses may struggle to stand, show signs of partial paralysis, or even die if treatment is delayed.

Common Symptoms of West Nile Virus in Horses

Horse owners should be aware of the wide range of clinical signs associated with the disease. Symptoms can vary from mild to severe and may include:

• Fever and weakness: Reduced energy and unwillingness to move.
  
• Neurological signs: Muscle twitching, stumbling, lack of coordination, or circling behavior.
  
• Abnormal behavior: Pressing the head against objects, confusion, or appearing “not quite right.”
  
• Difficulty standing or walking: Horses may collapse or show signs of partial paralysis.
  
• Severe cases: Horses unable to rise may require intensive veterinary care, and mortality rates can reach up to 30–40%.
  

Prompt recognition of these symptoms and immediate veterinary consultation can make a significant difference in recovery outcomes.

Treatment and Recovery

Currently, there is no specific antiviral medication for West Nile Virus in horses. Treatment is primarily supportive, which means veterinarians focus on reducing symptoms and giving the horse the best chance to recover. This often involves:

• Providing anti-inflammatory drugs to reduce fever and swelling in the nervous system.
  
• Offering fluids, nutrition, and round-the-clock supportive care.
  
• Using slings or support equipment for horses unable to stand on their own.
  

While many horses can recover with appropriate care, some may have lingering neurological issues even after surviving the illness.

Prevention: The Best Protection for Horses

The good news is that West Nile Virus in horses is largely preventable. Vaccination is the most reliable method to protect horses against the disease. Most veterinarians recommend yearly booster shots, typically administered before mosquito season begins.

In addition to vaccination, horse owners can take proactive steps to minimize mosquito exposure:

• Remove stagnant water: Buckets, troughs, and puddles should be emptied and cleaned regularly.
  
• Use stable fans: Mosquitoes are weak fliers and are discouraged by strong air movement.
  
• Turnout schedules: Avoid turning horses out at dawn and dusk when mosquito activity is highest.
  
• Apply safe repellents: Use products designed for equines to keep mosquitoes away.
  
• Stable management: Keep barns clean and use screens where possible to limit mosquito entry.
  

By combining vaccination with mosquito control strategies, horse owners can significantly reduce the risk of infection.

Why Horse Owners Should Stay Alert

Cases like these in Utah highlight the importance of continued vigilance. West Nile Virus is not new, but it is unpredictable. Each year, the number of cases can rise or fall depending on mosquito populations, climate conditions, and vaccination rates among horses.

For horse owners, this means staying proactive: ensuring vaccines are up to date, maintaining proper stable management, and being alert to any early signs of illness.

Final Thoughts

The recent confirmation of three positive cases of West Nile Virus in horses in Utah is a reminder that this disease is still present and dangerous. While the risk cannot be completely eliminated, it can be managed effectively through vaccination, mosquito control, and early detection of symptoms.

Protecting horses from West Nile Virus is ultimately about preparation and awareness. With proper care and preventive measures, owners can help keep their horses safe and healthy throughout mosquito season.

Reference: TheHorse.com (EDCC Health Watch, Sept 15, 2025)