Mere days after the state reported the season’s first human cases of West Nile virus, officials said there has been a jump in the number of mosquitoes testing positive for the illness, as well as more mosquitoes testing positive for Eastern Equine Encephalitis.

Between Aug. 6 and Aug. 13, 27 mosquito samples tested positive for West Nile, said John Shepard, assistant scientist with the Connecticut Agricultural Experiment Station. That adds up to about half of the total 57 positive samples for the season so far.

Also during that time period, a mosquito pool in Hampton tested positive for Eastern Equine Encephalitis virus. It’s the second sample in the state to test positive for EEE this season. The previous week, a sample from Stonington tested positive for EEE, which caused four human cases in the state last year — three of them fatal.

“The data shows that the virus is amplifying in the mosquito population and spreading to new locations,” said Philip Armstrong, a virologist and medical entomologist with the Connecticut Agricultural Experiment Station. “We are now entering the critical time during the summer when virus activity reaches its peak in mosquito populations and humans are at greatest risk to infection.”

Armstrong said he expects virus transmission to continue until mosquito populations decline in late September through early October.

New towns with West Nile-positive mosquitoes are New Haven, New Canaan, New Britain and Hartford. Additional West Nile-positive mosquitoes were identified in Bridgeport, Darien, Newington, Norwalk, Stamford and Wethersfield.

On Monday, the state Department of Public Health reported that a Waterbury resident was the first human West Nile case of the season.

Given that the mosquito season seems to be ramping up, Shepard said, residents should take measures to protect themselves from mosquito bites, such as eliminating standing water around the home, maintaining window screens to keep mosquitoes out of hose and using mosquito repellent.