Mosquitoes in Worcester have tested positive for West Nile Virus, the Massachusetts Department of Public Health announced Thursday.

No humans have tested positive for the virus, which is most commonly transmitted to humans by the bite of an infected mosquito.

The City of Worcester Division of Public Health and the Department of Inspectional Services have coordinated with the Central Massachusetts Mosquito Control Project to spray two designated areas of concern on Tuesday, Aug. 21 after sunset, up until midnight, officials say.

Residents within these areas should follow these spray precautions:

• Please close street facing windows and keep pets inside between sunset and midnight if possible to allow a more thorough application. This type of pesticide is similar to ones used for flea and tick control.

• Remain inside during the application and for 15-20 minutes afterwards.

• Accidental exposure is not expected to cause any health concerns in most people.

• No precautions are needed the day after the application as all residues will have evaporated.

• Residents with gardens are advised to wash off vegetables before consuming them.

• There is no need to cover pools as the spray is an oil-based product and will dissipate quickly.

• Any “outside air” controls on older window unit air conditioners should be turned off.

The public is urged to practice the Five D’s of prevention: Avoid being outdoors during DAWN and DUSK, when mosquitoes are most active; DRESS in long-sleeved clothing; use insect repellent with DEET; and DRAIN any standing water from around your home.

Tips for Avoiding Mosquito Bites:

• Be Aware of Peak Mosquito Hours – The hours from dusk to dawn are peak biting times for many mosquitoes.

• Clothing Can Help reduce mosquito bites.

• Apply Insect Repellent when you go outdoors.

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