August 14th 2025 - The Massachusetts Department of Public Health (MDPH) announced today that West Nile virus (WNV) has been detected in mosquito traps collected from Bedford and nearby communities. There have been no human cases of WNV identified in Massachusetts to date. The risk of WNV in Bedford remains high.
The MDPH tests mosquitoes for WNV from June to October and develops "risk maps" based on where WNV positive mosquito traps and human cases have been identified. Each risk level (low, moderate, high, and critical) has a corresponding list of actions that build on each other as risk level increases. Below you will find the seven action items to take when living in a high WNV risk community.
- Low: (1) check the MDPH’s arbovirus surveillance website; (2) repair screens, dispose of stagnant water; (3) wear mosquito repellant and long sleeves/pants during peak mosquito hours (dusk until dawn); (4) use mosquito netting on baby carriages and playpens.
- Moderate: Low action items, plus (5) wear mosquito repellant whenever outdoors; (6) dump standing water at least twice weekly.
- High: Low and moderate action items, plus (7) those who are over 50 years of age or older and/or those who are immunocompromised should adjust outdoor activity to avoid peak mosquito hours (dusk until dawn).
- Those over 50 years and those who are immunocompromised have been found to be at higher risk for getting sick with WNV if bitten by an infected mosquito. If you identify as being a part of either or both of these high-risk populations, the MDPH and Bedford Health Department encourages you to stay indoors during dusk until dawn to avoid peak mosquito hours and decrease your chance of being bitten by an infected mosquito.
Although no human cases have been identified in MA so far this year, August and September are the months when most human cases occur. WNV is most commonly transmitted to humans by the bite of an infected mosquito. The mosquitoes that carry this virus are common throughout the state, and are found in urban as well as more rural areas. While most mosquitoes are active in wetlands, the mosquitoes that commonly carry WNV like to be active in areas of standing water, like in catch basins, clogged rain gutters, unused tires, buckets, and other water holding containers.
Residents play an importat role in reducing the risk of WNV. By taking a few, common sense precautions, people can help to protect themselves and their loved ones.
Avoid Mosquito Bites
- Apply Insect Repellent when you go outdoors. Use a repellent with DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), IR3535 or oil of lemon eucalyptus [p-methane 3, 8-diol (PMD)] according to the instructions on the product label. DEET products should not be used on infants under two months of age and should be used in concentrations of 30% or less on older children. Oil of lemon eucalyptus should not be used on children under three years of age. Permethrin products are intended for use on items such as clothing, shoes, bed nets and camping gear and should not be applied to skin.
- Clothing Can Help reduce mosquito bites. Although it may be difficult to do when it’s hot, wearing long-sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.
- Be Aware of Peak Mosquito Hours - The hours from dusk to dawn are peak biting times for many mosquitoes. When risk is increased, consider rescheduling outdoor activities that occur during evening or early morning. If you are outdoors at any time and notice mosquitoes around you, take steps to avoid being bitten by moving indoors, covering up and/or wearing repellant.
Mosquito-Proof Your Home
- Drain Standing Water – Many mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes to breed by either draining or getting rid of items that hold water. Check rain gutters and drains. Empty any unused flowerpots and wading pools and change water in birdbaths frequently.
- Install or Repair Screens - Some mosquitoes like to come indoors. Keep them outside by having tightly-fitting screens on all your windows and doors.
Mosquito Control in Bedford
The Bedford Health Department continues to work with the MDPH and the Eastern Middlesex Control Project (EMMCP) to monitor local mosquito populations for mosquito-borne diseases.
Bedford’s robust mosquito control program includes annual helicopter application of biological larvicide to wetland areas in town, treatment of catch basins, and truck-mounted mosquito spraying. The most recent truck-mounted spraying event took place on July 15th, 2025. The next spraying event is planned for Monday, August 18th between sunset and 11:30PM. Mosquito spraying events are announced on the Health Department’s website at https://bedfordma.gov/197/Health-Department.
Information about WNV and reports of current and historical WNV virus activity in Massachusetts can be found on the MDPH website at: www.mass.gov/dph/mosquito and on the Bedford Health Department website at: https://bedfordma.gov/946/Mosquitoes.