West Nile Virus
Minimizing the threat of West Nile VirusWest Nile is a virus carried by mosquitoes that affects people, horses and many types of birds. Scientists do not believe the virus is spread from person to person or from animal to person. Mosquitoes get infected when they feed on an infected bird. Although the virus does not affect most humans and horses, WSDA considers this to be a serious threat to the state. Agency staff carries out many roles and responsibilities and is working with local, state and federal agencies to minimize the threat. Protecting horses and other equinesThe virus affects horses, mules, donkeys and other equines much more often than other animals. Most horses do not become ill and show no symptoms at all. Those that do become ill show signs such as loss of appetite, loss of coordination, confusion, fever, stiffness, muscle tremors and weakness. About one-third of horses that become ill die. Now is a good time to talk to your veterinarian about the West Nile virus vaccine. The vaccine requires two doses three to six weeks apart, and immunity may not be achieved until up to six weeks after the second dose. An annual booster should be given a few weeks to a month prior to the start of the mosquito season in your area. To minimize the threat of West Nile virus, control mosquito populations and prevent exposure to mosquitoes. Equine encephalitis is a reportable disease. Report suspected cases of West Nile virus in horses to:
For additional information on prevention of West Nile virus in equines and other livestock or poultry, visit the U.S. Department of Agriculture Web site. Mosquito ControlThe best way to minimize the threat of West Nile virus is to control mosquito populations and prevent exposure to mosquitoes. To control the mosquito population, empty old tires, buckets, plastic covers, toys and other containers around your home where water can accumulate and serve as a breeding ground for mosquitoes. Change water in birdbaths, fountains, wading pools and animal troughs weekly. To protect yourself from mosquito bites, wear long sleeved shirts and long pants when in mosquito-infested areas. You may also consider using a mosquito repellent. Additional control methods may be needed if mosquito populations rise above acceptable levels.Applying a larvicide, such as Bacillus thuringiensis var israelensis (Bti), may be the next best way to control mosquitoes. Larvicides are used to stop immature mosquitoes before they begin flying. WSDA has a list of pesticide products registered in Washington for use on mosquito larvae. However, many of these products may require a National Pollutant Discharge Elimination System (NPDES) Permit from the state departments of Ecology or Health. Further, certain ingredients, such as malathion or temephos, can only be used for larval control when allowed in emergency situations. Additional Information
American College of Physicians, Annuals of internal medicineJoint Statement on Mosquito Control in the U.S. |