Horse Owners Urged to Control Mosquito Populations

Horse Owners Urged to Control Mosquito Populations

“The most important thing farmers can do is to eliminate standing water around barns and other places where animals gather and mosquitoes breed," Helmick said.


West Virginia Commissioner of Agriculture Walt Helmick is warning horse owners in that state to control mosquito populations around the barn to minimize their animals' chances of contracting West Nile virus (WNV).

“Many insects, including mosquitoes, are likely to become active with the early warm weather we’ve experienced,” said Helmick. “The most important thing farmers can do is to eliminate standing water around barns and other places where animals gather and mosquitoes breed. Eliminating old tires or poorly draining areas can go a long way toward protecting your horses.”

Mosquitoes breed only in standing water, so drying out potential mosquito nurseries is critical to keeping their population in check.

He said that acting now—before vegetation becomes too thick—can make it easier to spot potential problem areas and correct them before mosquito populations explode. He also recommended that owners contact their veterinarians about having their horses vaccinated against WNV.

West Nile is a viral disease transmitted to horses by infected mosquitoes. Clinical signs of WNV include flulike signs, where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculations (twitching); hyperesthesia (hypersensitivity to touch and sound); changes in mentation (mentality), when horses look like they are daydreaming or "just not with it"; occasional drowsiness; propulsive walking (driving or pushing forward, often without control); and "spinal" signs, including asymmetrical weakness. Some horses show asymmetrical or symmetrical ataxia (incoordination). Equine mortality rate can be as high as 30-40%. Currently, no drugs exist to treat WNV specifically in horses. Treatment for an infected horse consists of supportive therapy to prevent the animal from injuring itself. Animal owners should consult their veterinarians if an animal exhibits any neurologic signs for testing.

The WNV vaccine for horses initially requires two doses administered three to six weeks apart. The vaccine takes four to six weeks from the second dose to achieve optimal effectiveness. Horse owners should consult with their veterinarians to choose a revaccination schedule to protect their horses effectively. It is also often recommended that if horses in mosquito-dense areas are vaccinated in the spring, a late summer booster should be administered for optimum protection.

WNV has been present in the United States since 1999 and is carried by mosquitoes that have bitten infected birds. An infected mosquito can then spread WNV to birds, humans, horses and other animals. WNV cannot be spread from one person to another.

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