CONCORD — Gov. John Lynch has signed a public health threat declaration, which allows numerous communities in the state to spray and take other preventive measures to stem mosquito-borne diseases, state health officials said.

The state Department of Health and Human Services mentioned the declaration on Thursday, a day after officials said the Eastern equine encephalitis virus was found in mosquitoes trapped in Sandown.

It is the first finding of EEE in the state this year, and the first time since 2010. In addition, 38 batches of mosquitoes have tested positive for West Nile virus this summer.

“This is the first identified positive for Eastern Equine Encephalitis in New Hampshire this season, but unfortunately it is not unexpected,” said Public Health Director Dr. José Montero. “What is different is that the U.S. is seeing an unprecedented outbreak of West Nile virus this year and that is even more reason why people should take precautions against being bitten by mosquitoes.”

Symptoms for West Nile include flu-like symptoms such as fever and headache. EEE is more serious. Symptoms may include high fever, severe headache, stiff neck and sore throat.