State health officials have reported new cases of eastern equine encephalitis and have expanded the region described as under "public health threat" to include Concord and several nearby towns.

So far this year, no humans have been infected with the disease, which is spread by mosquitoes and can cause brain swelling and death. But health officials said yesterday that a horse from Bow and a llama from Candia have recently tested positive for the disease.

Overall, three animals have tested positive this season, as have 23 mosquito pools in the state. There have been no positive tests so far for West Nile Virus, another brain illness spread by mosquitoes.

The newly classified communities include Allenstown, Bow, Chichester, Concord, Dunbarton, Epsom and Hopkinton.

Placing communities under public health threat allows them to get state funding to help cover the costs of mosquito-abatement plans and insecticide spraying, if they choose to apply. It also allows the communities to speed up the permitting process for mosquito control.

State health officials urged residents to avoid mosquito bites by wearing long pants and sleeves, staying inside at dusk and using insect repellents. Eliminating pools of standing water will also slow mosquito breeding.

EEE is likely to remain a threat until the first hard frost.

MARGOT SANGER-KATZ