Eastern Euine Encephalitis: Reduce your Risk
State officials announced recently that mosquitoes carrying Eastern equine encephalitis (EEE, also called Triple-E) have been found in Danville. EEE is a mosquito-spread disease that mostly affects birds. The disease appears sporadically in New Hampshire, with outbreaks lasting one to three years. Occasionally this disease is transmitted via mosquito bite to horses or to people, although only a few of New Hampshire’s 47 mosquito species can actually transmit EEE to mammals.
Last year, New Hampshire led the nation in human EEE infections,
with seven reported cases resulting in two deaths. The death rate
is high in people (and horses) infected with EEE, even though the
risk of becoming infected is very low. Furthermore, while we have
a vaccine to protect horses, we don’t yet have a vaccine that protects
humans. Fortunately, there are precautions people can take to avoid
Although most EEE cases occur in the southeastern part of the state,
especially Rockingham County, mosquitoes that transmit EEE do show
up in other parts of the state, so all Granite Staters should take
precautions to protect themselves. Individuals can dramatically reduce
their risk of getting EEE in several ways:
- Use insect repellant containing DEET or picaridin when you are outdoors during mosquito season, and/or wear clothing that doesn’t expose skin.
- Try not to spend time outdoors within an hour or so of dusk.
- Don’t walk through thick, brushy woods without protection.
- Adjust window screens and doors to keep mosquitoes out of your home.
- If you own a horse or donkey, have your animals vaccinated.
Mosquito traps aren’t likely to help, and spraying mosquito larvae
requires training, licensing, special equipment, and special permits.
Adult mosquitoes fly so far that treatment by individual landowners
doesn’t make much sense.
For more information about EEE and ways to manage its risks, see the UNH Cooperative Extension's EEE fact sheet (contains information about West Nile Virus, another mosquito-borne illness that sometimes strikes humans).