On Tuesday, the Massachusetts Department of Public Health increased the level of risk throughout the state for the low to moderate Western Nile virus.
It is only the second time that public health officials have raised the level of risk at the state level.
There are no reported cases of humans or animals contracting West Nile, but more than 160 communities in the state are already at moderate risk for the virus, which is transmitted by mosquitoes.
Symptoms include high fever and flu-like symptoms. Most people taking West Nile show no symptoms. Those over 50 are more at risk of contracting the virus.
Public health commissioner, Dr Monica Bharel, said the recent warm and humid weather, coupled with heavy rains, provided the ideal conditions for virus-carrying mosquitoes
"I strongly encourage everyone to continue to use insect repellents and to be particularly mindful of the activity of mosquitoes at dusk and dawn when the risk of being bitten by mosquitoes is greater, "Bharel said in a statement.
Mosquitoes tested positive for the virus this summer in several cities in Massachusetts, including Boston, Dracut and Weymouth.
Cynthia Fernandez can be reached on firstname.lastname@example.org. Follow her on Twitter @CynthFernandez .