HADLEY, Mass. (WWLP) – The Massachusetts Department of Public Health (DPH) has detected West Nile-infected mosquitoes in 17 municipalities in the state so far in 2023.

The City of Holyoke announce Wednesday that a mosquito sample tested positive for West Nile Virus on August 3rd.

Here’s when and where 28 mosquitoes with a positive WNV were found.

1. Brookline 7/2
2. Pittsfield (2) 7/7, 7/18
3. Worcester (2) 7/7, 7/20
4. West Springfield (2) 7/14, 7/21
5. Boston 7/18
6. Haverhill 7/24
7. Watertown (6) 7/25
8. Hadley 7/26
9. South Hadley 7/26
10. Burlington 8/1
11. Waltham 8/1
12. Quincy 8/2
13. Holyoke 8/3
14. Stoneham 8/7
15. Woburn 8/7
16. Halifax 8/7
17. Kingston 8/7

The season’s first West Nile virus-positive mosquito sample was confirmed by the Massachusetts State Public Health Laboratory from a mosquito sample collected on July 6 in the town of Brookline in Norfolk County. 

“We often find the first evidence of WNV in mosquitoes at about this time every year,” said Public Health Commissioner Robert Goldstein, MD, PhD. “We are asking people to start taking steps now to avoid mosquito bites. While WNV can cause serious illness, there are simple things that you can do to protect yourself and your loved ones.”

“With the recent rain and the warmer weather, mosquito populations will increase and we will start to see more of them carrying WNV,” said Dr. Catherine M. Brown, State Epidemiologist. “Use a mosquito repellent with an EPA-registered ingredient, wear clothing to reduce exposed skin, drain standing water and repair window screens. We also encourage everyone to make it a habit to visit DPH’s mosquito-borne disease web pages so you know when and where WNV activity is occurring.”

Bug spray with ingredients like DEET and picaridin works best, especially now as we head into August and September when West Nile cases typically peak.

Tips to avoid mosquito bites:

• When outdoors, wear long pants, a long-sleeved shirt, and socks.
• Use a repellent with DEET according to the instructions on the product label.
• Keep mosquitoes out of your house by repairing holes in screens and making sure screens fit tightly to doors and windows.
• Schedule outdoor events to avoid the hours between dusk and dawn when mosquitoes are most active.
• Remove areas of standing water around your home twice a week to eliminate sources of mosquito breeding.

West Nile virus (WNV) first appeared in the United States in 1999. Since the initial outbreak in New York City, the virus has spread across the U.S. and was identified in birds and mosquitoes in Massachusetts during the summer of 2000.