Don’t be afraid; be alert.

That’s the advice of public health officials, doctors and veterinarians around Maine about the threats of mosquito-borne West Nile virus and eastern equine encephalitis, or EEE. Neither disease has been reported in Maine this year, but cases of the diseases — which can be fatal for humans, birds and mammals, especially horses — have been widely documented elsewhere. West Nile virus has been found in parts of Massachusetts, and mosquitoes with the virus recently were discovered in monitoring pools in New Hampshire. The first human case in Connecticut was diagnosed this week.

“We have not yet seen eastern equine encephalitis or West Nile virus” in Maine this year, said veterinarian Anne Lichtenwalner, director of the University of Maine Animal Health Lab in Orono. “But I expect that we probably will. … I think we should be very aware. I think we should be vigilant.”

Lichtenwalner said officials have been educating people about the illness and how to prevent its spread. In addition, regular monitoring of designated pools around the state is occurring, and the results — no virus detected — have been encouraging.

Still, with West Nile reaching into New Hampshire, that’s cutting it a little close for southern Maine and the numerous horse farms from Arundel to Durham. Added to that, this summer’s hot, often humid days, interspersed with periods of rain, create favorable breeding conditions for mosquitoes.

“Be forewarned and be knowledgeable,” said state epidemiologist Dr. Stephen Sears. “People need to be alerted.” He said he can’t predict when West Nile will spread to Maine. “I can only look to the south and say, ‘It’s there.’”

With autumn approaching, it might seem that the risk will diminish. In fact, said Sears, the virus is often detected from mid-August through the end of September and even into early October.

The drought in the Midwest has been pegged as a possible cause for the extensive spread of the virus, on the theory that mosquitoes that are unable to find stagnant pools of water for breeding there might be migrating beyond their usual territories and delivering the virus to new locations.

West Nile virus has caused a flurry of alarm in several parts of the country, including Texas. Thursday, the mayor of Dallas declared a state of emergency because of it and ordered the first aerial spraying of insecticide in nearly a half century. Nine cases have been reported in Ohio, and according to the Centers for Disease Control in Atlanta, the virus this year has penetrated into 43 states. Almost 700 people have been afflicted nationwide — the most since West Nile virus was first reported in the United States in 1999 — and 26 deaths have been attributed to the virus.