Mosquitoes test positive for West Nile in Easton, Stamford

West Nile season seems to be picking up in the state, as 10 mosquitoes tested positive for the disease for the second week in a row.

In addition, a horse in Easton has been infected with the illness, though there have been no human cases to date.

In the latest report from Connecticut Agricultural Experiment Station, posted Tuesday, the state reported that during the week of Aug. 4, 10 mosquitoes tested positive in nine towns, including Stamford, Greenwich, East Haven (where two tested positive for the illness), North Haven and New Haven.

The state also reported that four mosquitoes tested positive for Eastern Equine Encephalitis this week, in Voluntown and Madison.

“Virus activity is picking up,” said Philip Armstrong, a virologist and medical entomologist with the Connecticut Agricultural Experiment Station in an email. “We saw a major expansion of West Nile virus in mosquitoes throughout the state to include a number of new towns.”

A few weeks ago, the state’s West Nile season seemed to be off to a slow start, but Armstrong and others said that was likely to change.

Armstrong said more test results were expected to come in on Tuesday, and there might even be more towns where West Nile is present.

In addition to the West Nile-infected horse in Easton, Armstrong said there have been two horses infected with Eastern Equine Encephalitis, from Colchester and Columbia.

In total this season, 23 mosquitoes have tested positive for West Nile and 11 have tested positive for Eastern Equine Encephalitis. There also have been a total of 20 mosquitoes that have tested positive for the lesser-known Jamestown Canyon virus.

Last season was the worst on record for prevalence of West Nile in Connecticut, with a total of 393 positive mosquito samples collected from 65 sites in 53 municipalities. The state reported 23 human cases of West Nile, and one death — the first since 2006.

West Nile virus is the leading cause of mosquito-borne illness in the United States, including Connecticut. Several mosquito species in Connecticut can carry West Nile. The symptoms of infection can range from mild to severe. There is no vaccine to prevent or medicine to treat infection with West Nile.