BOSTON (AP) — State health officials have confirmed a case of mosquito-borne Eastern equine encephalitis in a horse in Tyngsborough, the third case in a horse this year.

The health department said Wednesday it is raising the mosquito threat level to "critical" in the north central Massachusetts community. Nearby Chelmsford, Dracut, Dunstable, Groton, Lowell, and Westford have been raised to "moderate" risk.

Belchertown in western Massachusetts has already been "critical" after EEE was found in two horses there, and nearby Amherst is rated "high." Several southeastern Massachusetts communities are considered at "high" risk.

Areas rated "critical" or "high" are urged to cancel outdoor events in the evening when mosquitoes are most active.

A Weymouth woman in her 80s who died last month is the only confirmed human EEE case this year. There were seven last year.