The threat of the rare but potentially fatal mosquito-borne virus Eastern equine encephalitis (EEE) has ramped up in recent weeks across the state of Massachusetts as more communities’ risk levels rise to “moderate,” “high” and even “critical” condition, including those in the Pioneer Valley.

The town of Amherst is currently at moderate risk while Granby, at Amherst’s southern town line, is at critical, the highest possible level, according to the Massachusetts Executive Office of Health and Human Services (EOHHS).

The moderate risk level indicates EEE-infected mosquitoes are present in the area or have been in the past year. Prevention methods at this level include the use of insect repellent from sunset to sunrise and avoidance of outside areas with high mosquito activity, such as marshlands, EOHHS explains.

The article also added that areas with high and critical levels require more drastic prevention methods such as canceling, adjusting or rescheduling outdoor activities and gatherings that fall between the hours of dusk and dawn, when mosquitoes are most active.

The University posted a statement on Aug. 31 saying it is “working closely with the Massachusetts Department of Public Health and other Amherst agencies and institutions regarding mosquito activity, surveillance and the appropriate response.”

Both Amherst and UMass emphasize that mosquito bite prevention is the best method to reduce the risk of contracting EEE. This includes wearing long sleeves and pants when mosquitoes are active and also emptying sources of standing water where mosquitoes breed, such as flower pots, bird baths, garbage cans and children’s play pools.

The town of Amherst also advises using mosquito netting on baby strollers and children’s playpens.

“The Amherst risk level for EEE has been raised to moderate (on a scale of low, moderate, high and critical) due to activity in surrounding areas,” according to the town of Amherst. The risk level of West Nile Virus, another serious mosquito-borne virus, remains “low.”

Nearby communities listed at “high” EEE risk, the second highest level, include Ludlow, Belchertown, South Hadley and Chicopee.

Springfield, Pelham, Holyoke, Hadley, Palmer, New Salem and Ware remain at moderate risk like Amherst, while the Western Massachusetts communities Colrain and Heath, along the Vermont border, are also listed as critical.

Communities such as Northampton, Easthampton, Hatfield, Sunderland, Shutesbury, Deerfield, Leverett and Whately remain at “low” risk as of right now. The EOHHS’ 2019 Massachusetts Arbovirus Daily Update provides new information as it becomes available.

EEE is a potentially deadly virus that can affect those of all ages and can cause brain infections, also known as “encephalitis.” While rare, the Centers for Disease Control and Prevention warns “Approximately 30 [percent] of people with EEE die and many survivors have ongoing neurologic problems.”

Other symptoms include sudden onset headache, high fever, chills and vomiting and could progress toward disorientation, seizures or coma, the CDC explains.

Symptoms tend to develop four to 10 days after a bite from an infected mosquito as the virus incubates. The disease cannot be spread directly from person to person nor via other infected animals to humans or vice versa.

Out of seven human cases so far confirmed in Massachusetts in 2019, a woman from Fairhaven has died and seven horses across Middlesex, Essex, Norfolk, Hampshire and Worcester counties which contracted the virus have since been euthanized, according to the Boston Globe.

Additionally, a goat in Bristol County and an eighth horse were also infected, according to EOHHS.

As there is no human vaccine or specific treatment to limit exposure. The CDC also advises a number of the aforementioned methods in addition to ensuring secure screens on windows and doors to prevent mosquitoes from entering dwellings.

“Use insect repellent containing DEET, picaridin, IR3535 or oil of lemon eucalyptus on exposed skin and/or clothing,” the CDC added.

Mass.gov warns that DEET should not be used in excess of 30 percent on children and should not be used at all on infants under two months of age, while children under the age of three should not be exposed to oil of lemon eucalyptus. Products containing permethrin should not be applied to the skin, regardless of one’s age, and are only intended for objects such as clothing and camping gear, it added.

Massachusetts is particularly susceptible to the disease alongside New Jersey and southern states such as Florida and Georgia, which have the highest number of cases, says the CDC. On average, only 7 cases are reported annually nationwide.

“EEE occurs sporadically in Massachusetts, with the most recent outbreak years occurring from 2004-2006 and 2010-2012,” according to the town of Amherst.

The Mass Public Health Blog, under Mass.gov, explains that mosquito season extends beyond Labor Day weekend, the “unofficial end of summer,” and does not in fact end until the first hard frost of the season when mosquitoes can no longer survive.

Chris McLaughlin can be reached at [email protected] and followed on Twitter at @ChrisMcLJournal.