Mosquito season isn’t over yet, and health officials are asking residents across the region to take it seriously. The Northeast Massachusetts Mosquito Control and Wetlands Management District has raised the West Nile virus (WNV) risk level to high in Revere and Winthrop, citing an increase in WNV detections in mosquito samples collected across the region, the Revere Journal reported on September 9.

The advisory adds two more communities to a cluster that already includes Chelsea. On September 4, the Massachusetts Department of Public Health (DPH) announced the season’s sixth human WNV case in the state — a man in his 70s most likely exposed in a part of Suffolk County outside Boston — and elevated risk levels to high in Chelsea, Malden, Revere and Winthrop as a result, according to the DPH press release. The same release states that WNV risk is now high in 11 municipalities statewide, and separately names Boston, Brookline, Cambridge, Everett, Newton, Somerville and Watertown as also being at high risk — though the release doesn’t spell out the full 11-town list or confirm those seven were already high-risk before this announcement, so the complete statewide picture is a bit unclear from the source itself.

The numbers behind the warning are substantial. DPH reported 273 WNV-positive mosquito samples so far this year, detected in Barnstable, Berkshire, Bristol, Dukes, Essex, Franklin, Hampden, Hampshire, Middlesex, Norfolk, Plymouth, Suffolk and Worcester counties, since the season’s first positive sample turned up on June 16. Eastern equine encephalitis (EEE) has also been detected in 13 mosquito samples this year, though no human or animal EEE cases have been reported so far.

In the DPH release, Public Health Commissioner Robbie Goldstein urged residents heading into the holiday weekend to use mosquito repellent, wear clothing that reduces exposed skin, and empty anything around the house that could collect standing water.

The prevention guidance from both agencies lines up closely. Residents are urged to apply an EPA-registered insect repellent when outdoors, and to limit outdoor activity during dusk-to-dawn hours, when many mosquito species are most active. Long sleeves, long pants and socks can also help reduce exposure. Around the house, DPH and Northeast Mosquito both recommend draining standing water — checking gutters and drains, emptying unused flowerpots and wading pools, and changing water in birdbaths frequently — and making sure window and door screens fit tightly. WNV can infect people of any age, but Northeast Mosquito notes that people over 50 face a higher risk of severe illness.

Revere residents have one practical option this week: Northeast Mosquito is still taking requests for free mosquito spraying, with a week left in the window. Residents can call (978) 352-2800 to request service or (781) 485-8486 for more information.

For Chelsea-area readers, the Revere and Winthrop advisory isn’t really new information so much as a reminder that the whole cluster — Chelsea included — is still in an active high-risk window. The precautions apply just as much at home as they do a few blocks away.