West Nile mosquito

West Nile Virus has been detected in mosquito samples in Arlington, Christine Bongiorno, director of health and human services, reports.

The Massachusetts Department of Public Health announced Thursday, July 28, that the virus was also found in samples taken in Boston and Waltham. Positive mosquito samples were detected in Worcester, Brookline and Malden earlier this summer.

The state agency reports that although there have been no human cases of West Nile infection reported in the state this year, the current warm weather and pattern of precipitation events have produced large mosquito populations among the species most likely to spread the virus.

As a result of these findings, the state has raised the risk level for human infection in the communities of Arlington, Belmont, Boston, Cambridge, Newton, Waltham and Watertown from low to moderate.

"While this is not cause for serious alarm, residents should be aware that West Nile Virus was found in mosquitoes in Arlington and take extra steps to avoid contact with the insects," Bongiorno said in a news release. "Stay indoors if you can during peak hours and take proactive measures at your home to keep mosquitoes outside."

To avoid contracting the virus the Arlington Health Department recommends that residents follow tips:

Mosquito-proof your home

• Drain standing water. Mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes to breed by either draining or discarding items that hold water. Check rain gutters and drains. Empty any unused flowerpots and wading pools, and change water in bird baths frequently.

• Install or repair screens. Keep mosquitoes outside by having tightly-fitting screens on all of your windows and doors.

Avoid mosquito bites

• Apply insect repellent when outdoors. Use a repellent with DEET or oil of lemon eucalyptus. DEET products should not be used on infants under two months of age and should be used in concentrations of 30 percent or less on older children. Oil of lemon eucalyptus should not be used on children under 3 years old.

• Be aware of peak mosquito hours. The hours from dusk to dawn are peak biting times for many mosquitoes. Consider rescheduling outdoor activities that occur during evening or early morning.

• Clothing can help reduce mosquito bites. Wearing long-sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.

West Nile is most commonly transmitted to humans by the bite of a mosquito infected with the virus. DPH reports that there were 10 human cases of WNV in 2015. While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe infection.

The Town of Arlington works to prevent the breeding of mosquitoes by treating all storm water catch basins in town, treating wetland areas and working with property owners to remove large sources of standing water, such as abandoned swimming pools. For more information about the virus, click here >>

This announcement was published Friday, July 29, 2016.