Take Measures Now to Protect Yourself and Your Horse from Eastern Equine Encephalitis (EEE)

With July coming upon us soon and while most people are thinking about barbecuing and fireworks, rainfall over recent weeks is a good reminder to think about mosquitoes and protecting not only ourselves but also pets.  In 2013, we had 13 veterinary cases of Eastern Equine Encephalitis in a cluster of six southeastern counties.  Eight of those cases occurred from July-early August.  Brunswick County recorded the first case (confirmed in mid-July) but Cumberland county led the way with six cases and Pender County had three.   In 2012, Cumberland and Brunswick County recorded the only cases but they were recorded closer to September.  What this tells us is that we can't predict where and when the disease might occur.

Horse owners may want to check their inoculation records to make sure that their horses' inoculations are still effective (which they should be if the horses were inoculated in the spring) but remember that a booster inoculation is important about 6 months later.

Despite the name, the disease affects not just horses but people as well.   Unlike some other disease-causing viruses of medical importance, you can't get EEE from contact with an infected person or horse.   Mosquitoes become infected when they bite an infected bird and those mosquito species then feed on other birds which increases the reservoir of virus in the bird population during the course of the summer.  Other mosquito species acquire the virus when they bite infected birds and then act as "bridges" by passing the virus to horses or people on whom they subsequently feed and which then become infected.  

Children and the elderly are the biggest concern, so make sure to take appropriate protective measures and use insect repellents (see http://insects.ncsu.edu/Urban/repellents.htm).  We still recommend the usual measures of emptying rain-filled containers and other objects as well as unclogging gutters, drainage ditches, etc.  However, mosquitoes that can transmit EEE will also breed in floodwaters and salt marshes and for that reason personal protection is critical. Many of these mosquitoes are active at dawn and dusk and so altering our activity times can help (but are not a guarantee against mosquito bites).  Again, we also urge horse owners to consult with their veterinarian about vaccinating their animals against these mosquito-borne diseases.

I would also add that people with dogs that spend a great deal of time outdoors need to make sure they are keeping up their pet's monthly medications since some of the same mosquito species that are increasing in numbers can also transmit dog heartworm.  

Written by: Mike Waldvogel, NC State University Extension Specialist- Entomology