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Veterinary Division

Disease Alert- West Nile Virus (WNV)

NCDA&CS West Nile Related Press Releases - 2008

Precautions to take to protect Equine

Reduce Mosquito Breeding Sites

You can decrease the chance of your animals’ being exposed to the virus by limiting their exposure to mosquitoes. The best way to do this is to reduce mosquito breeding sites.

Mosquitoes can breed in any puddle that lasts more than 4 days. The best way to reduce your risk is to remove any potential sources of standing water in which breeding can take place.

  • Dispose of water-holding containers such as old tires.
  • Drill holes in the bottom of containers that are left outside.
  • Thoroughly clean watering troughs, bird baths, etc., every few days.
  • Clean clogged roof gutters every year.
  • Turn over wading pools or wheelbarrows when not in use, and do not let water stagnate in bird baths.
  • Aerate ornamental pools.
  • Clean and chlorinate swimming pools that are not in use and do not let water collect on pool covers.
  • Use landscaping to eliminate low spots where standing water can collect.

Screened Housing
Well-maintained insect screening can be useful to reduce exposure to adult mosquitoes if precautions are taken to first eliminate mosquitoes from inside the structure. Fans may reduce the potential ability of mosquitoes to feed on horses.

Insect Repellant
Using insect repellants may help decrease exposure of horses to adult mosquitoes. Because under certain conditions (e.g., perspiration) some products have a limited duration of effectiveness, it is not wise to rely solely on repellants to prevent mosquito exposure. Use repellants according to label instructions. Products containing a synthetic pyrethroid compound (such as permethrin) as the active ingredient serve two purposes: (1) they offer superior safety and repellent efficacy and (2) they are contact pesticides that kill mosquitoes.

Outdoor Exposure
Mosquito species vary in their feeding habits, making transmission possible at any time of day or night. However, a recent epidemiologic study of WNV suggests that keeping horses in stalls at night may be helpful in reducing their risk of infection.

Information from USDA-AHPIS web site

CDC National Center for Infectious Diseases: West Nile Virus - General information and prevention information

CDC West Nile Virus - Question and Answer

EPA: Pesticides and Mosquito Control

National Biological Information Infrastructure (NBII)- This site includes latest news about WNV, information about human health effects associated with WNV, and state and regional information.


Brochures from N.C. Department of Environment and Natural Resources



NCDA&CS Veterinary Division, Dr. R. Douglas Meckes - State Veterinarian
Mailing Address:1030 Mail Service Center, Raleigh, NC 27699-1030
Physical Address: 2 W. Edenton Street, Raleigh, NC 27601
Phone:919-707-3250; FAX: (919) 733-2277