Guilford is one of seven Connecticut towns to have a mosquito test positive for West Nile virus (WNV) this month, according to Health Director Dennis Johnson.

The other towns with positive tests are Bridgeport, Darien, Greenwich, Newington, Norwalk, and Stamford, according to the Department of Energy & Environmental Protection.

The town received the results of the test early last week, Johnson said, as officials around the state continue to stay wary of mosquito-borne illnesses late in the summer, when insect populations ramp up.

Connecticut has had 88 confirmed human cases of WNV since 2010, according to the Connecticut Department of Health and the Centers for Disease Control & Prevention (CDC), including one in Guilford.

The year 2018 was the worst on record for WNV in Connecticut, with 23 cases and one death, according to data from the state.

The virus was introduced to Connecticut in 1999, according to Johnson. It causes no symptoms in 80 percent of those infected, but according to the CDC, 1 in every 150 cases are severe and can cause paralysis, convulsions, and high fevers, particularly in the elderly and those with underlying health conditions.

WNV is not nearly as large a concern as eastern equine encephalitis (EEE), a mosquito-borne disease that is significantly more dangerous to humans, according to Johnson, though the town continues to monitor cases of WNV in the town. EEE can potentially causing swelling in the brain.

The first mosquito with EEE was found in Connecticut this week, Johnson said, in Stonington, which has habitats favorable to the species of mosquito that carries the disease.

EEE killed three Connecticut residents last summer, according to Johnson, with four total confirmed cases, and prompted the cancellation of outdoor events, including some in Guilford.

The positive WNV case will not precipitate any immediate action in the town, Johnson said, though he warned that cases can multiply relatively rapidly.

“The population of infected mosquitoes sort of amplifies as they go further into the summer,” Johnson said. “It will expand and get more amplified over time, and we’re just seeing the start of it at this point. In another month or so, five weeks are so, you’re probably likely to see more cases.”

Larvicide treatments meant to keep mosquito populations down have been carried out regularly in 21 locations around the town since April, Johnson said.

Mosquitoes are tested weekly in Guilford, according to Johnson, though it takes a few days to receive the results of the tests.

Johnson said he did not know the exact “threshold” for the number of cases before the state Department of Health would urge further action, likely beginning with localized aerosol spraying from trucks, which officials try to avoid due to the toxic effect these treatments have.

Neighbors would be warned, and the spray would be carried out in “a very controlled fashion,” though there is additionally a danger of collateral damage to other creatures, particularly aquatic life in marshes, Johnson said.

There is also the potential to cancel evening activities—outdoor athletic events in particular, according to Johnson, though that would depend on significant more positive tests of human infections.

In the meantime, Johnson said it can’t hurt to avoid mosquito-heavy areas when possible, with the edge of forests and woodlands being the most likely places to encounter mosquitoes, and dusk being the most likely time for mosquito activity.