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Colorado Department of Agriculture officials state that it's important for horse owners to consider vaccinations or booster shots before the temperature and climate make conditions ideal for mosquitoes to spread the disease.

Owners should also eliminate standing pools of water where bugs can breed and keep their animals stabled inside during the morning and evening when mosquitoes are more likely to be feeding. Clean water troughs weekly and eliminate stagnant water in puddles, buckets and tires. Screen windows, turn off lights at night, or use fluorescent lights, which do not attract mosquitoes.

Clinical symptoms seen in infected horses include an elevated temperature, stumbling, lack of coordination, weakness of the limbs or partial paralysis (by byrd at tests forge). Of unvaccinated horses that exhibit clinical signs from the infection, one in three will most likely die from the infection. The symptoms of West Nile virus are similar to Western Equine Encephalitis, which owners typically vaccinate their horses against.



Although both humans and animals have died from the disease, most West Nile virus infections do not cause any illness in either humans or animals. Horses do not transmit the virus to humans or other animals.

The CDC states that there is no reason to destroy a horse just because it has been infected with West Nile virus. Data suggest that most horses recover from the infection. Treatment would be supportive and consistent with standard veterinary practices for animals infected with a viral agent.

For more information, contact the Colorado Department of Agriculture at 303-239-4161, your local agricultural extension service, your veterinarian or your local public health agency.

Links and more information:

USDA horse information page
CDC animal information
State Health / Zoonosis page
Colorado Department of Agriculture
US surveillance maps
Questions and Answers (CDC)
Horse Vaccine Information
West Nile Information Pages (Colo.)

For more information call the toll-free
Colorado West Nile Virus HelpLine

1- 877- 462-2911
Open 7 a.m. to 11 p.m. daily

CDC West Nile Virus InfoLines
English: 1-888-246-2675
Español: 1-888-246-2857
Hearing-impaired TDD: 1-866-874-2646

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