Reducing Your Horse's Exposure to Mosquitoes
	Auburn, August 30, 2002 --- One of the most important steps horse owners can take to reduce 
their horses' exposure to diseases such as West Nile virus and Eastern equine encephalitis is to reduce 
their animals' exposure to mosquitoes as well as vaccinate the animals against both diseases.  
Mosquitoes are the primary carriers of both diseases.
	First, horse owners should control mosquito populations by removing all potential sources of 
stagnant water in which mosquitoes might breed.  Mosquitoes can breed in any puddle that lasts more 
than four days. 
	Livestock watering troughs should be thoroughly cleaned on a monthly basis.  Troughs should be 
dumped and refilled on a weekly basis if they are small enough to handle easily.
Housing animals in structures with well-maintained insect screening can reduce exposure to adult 
mosquitoes.   However, these mosquito-resistant structures may actually lead to mosquito exposure 
unless precautions are first taken to eliminate mosquitoes from inside the structure. This can be done in a 
variety of ways including the use of pesticides targeting all life stages of mosquitoes. In addition, using 
fans may reduce the potential ability of mosquitoes to feed on horses. 
A recently completed study of WNV suggests that keeping horses in stalls at night may be helpful 
in reducing their risk of infection. 
	Use of insect repellents may decrease exposure of horses to adult mosquitoes. Due to practical 
limitations in the coverage area that may be achieved and the limited duration of effectiveness, repellents 
should not be solely relied upon to prevent exposure. 
Repellents should be used according to label instructions regarding appropriate species, method 
of application and other precautions. Topical application of a product containing a synthetic pyrethroid 
compound (e.g., permethrin) as the active ingredient may offer the best combination of safety and 
effectiveness.

SOURCE:  Dr. Cindy McCall, Extension animal scientist