Health officials in Stamford say residents should be extra careful outdoors this holiday weekend amid a large spike in mosquitoes carrying the West Nile virus.

State researchers say traps in Stamford have collected more than half of all the West Nile-infected mosquitoes in Connecticut. The threat caused Gov. Dannel Malloy to come to the city this week to raise the alarm.

Around Cove Island, the city even went door-to-door to warn nearby residents.

Officials urge the use of insect repellent, but some residents are not on board, saying they won't use it because of the chemicals.

Health officials say the all-clear is usually given by mid- to late September, when the mosquito population begins dying off fairly quickly.