Local agency helps protect homes from virus-carrying mosquitoes during peak season.

·5 min read

Mild weather this past winter will likely mean an increased risk of West Nile virus and Eastern Equine Encephalitis this fall, health officials are warning.

Summer is the peak breeding season for mosquitoes, and a mild winter means they can breed earlier, increasing their populations and the risk of transmission of West Nile and EEE in the autumn.

“Mosquito-borne viruses are typically more prevalent in the fall,” said Lauren Saunders, the director of public health in Gardner. “In general, when there are milder winters, which we had last year, experts expect to see more mosquitoes earlier in the season. An earlier mosquito season allows them longer to breed, which increases overall population.”

Saunders emphasized the importance of mosquito control during peak summer. The Central Massachusetts Mosquito Control Project (CMMCP) can be vital to reducing the mosquito population.

June through October are what CMMCP officials call “vector” months, the peak for mosquitoes to breed.

The CMMCP advises that homeowners request a spot on the pesticide spray schedule to protect against mosquitoes and to take preventive measures at home. Requests for individual spray treatments have been open since May 31.

Mosquito repellant safe for humans, other animals

Timothy D. Deschamps, executive director of the CMMCP, said the type of pesticide being sprayed is a 4% low-concentration solution. Because mosquitoes are soft-bodied insects, it requires just a small amount of pesticide to control their population.

CMMCP personnel spray pesticide during the evening when there is low residential activity, and it only takes 15 to 20 minutes to settle into the environment and it is safe for pets and owners to come out of their homes, Deschamps said.

“There has been a lot of testing done by the Environmental Protection Agency that shows minimal negative aspects to both the environment as well as human and other populations,” Deschamps said. “Since we are doing it at night, when people tend to be inside, as opposed to the mosquitoes that are actively seeking blood meals while we are doing our applications.

Deschamps emphasized that the pesticide is safe for wildlife.

“This type of pesticide is also a nonresidual type of pesticide, which means the very next day there are no residues left on any of the areas that we do the applications,” Deschamps said. “Honeybees and other beneficial insects would not be impacted by our programs.”

Why the agency was founded

The Central Massachusetts Mosquito Control Project was established in 1973 to tackle the rising cases of mosquito-borne viruses in 44 cities and towns in Worcester and Middlesex counties. According to Saunders' records, the CMMCP has been collaborating with the Gardner Health Department since 2017 to combat EEE and West Nile.

There are eight core services that the CMMCP offers to central Massachusetts, from pesticide spraying to educational programs for higher-risk groups. For more information on the available services, visit the Central Mass Mosquito Control Project online at www.cmmcp.org/services.

“We have an adulticide spray program, which is done by request from area residents or in response to mosquito-borne viruses that are identified at the area,” Deschamps said. "We have a tire recycling program because tires that are left in the environment are suitable habitats for several species of mosquito larvae to develop. These species will often transmit the West Nile virus to people.”

According to Deschamps, the point of contact for educational programs in communities like Gardner are the health department and school boards in early May and June before the peak of the breeding season. Educating high-risk groups, which include adults over 50 years old, children under 15 and immune-compromised people, is key to keeping communities safe from an epidemic of mosquito-borne viruses.

Mosquitoes thrive near still water

Both Deschamps and Saunders said there are many precautions people can take, especially if a family member belongs to one of the high-risk groups.

A common mistake people make is leaving items outside, like small kiddie pools, plastic toys that can retain water and piles of wood.

“Look out for any container that can hold water for more than a week and they should be covered or put inside or discarded. Those areas can cause species to develop on a regular basis,” Deschamps said.

"We also do recommend people to listen to their local news media as well as to their health departments to be alert if there are any mosquito-borne viruses in the area and, if they are in areas of high mosquito populations, to use an Environmental Protection Agency-approved approved repellent to minimize your exposure to bites," Deschamps said.

Worcester County is a low-risk area for both EEE and West Nile virus, according to the state Department of Public Health. Mosquito-borne virus surveillance in Massachusetts started last month, and will continue through the fall. For updates, visit www.mass.gov/info-details/massachusetts-arbovirus-update.

Drought conditions lead to more mosquitoes

Due to the low levels of rain, Central Massachusetts is in a short-term drought, which creates a moderate to minimal risk for a spike in the mosquito population.

“We are currently in a bit of moderate drought in most of our communities and we are seeing a bit of a suppressed mosquito population at this time,” Deschamps said. “However, our surveillance traps have identified increasing populations of a species called the cattail mosquito which develops in these cattail swamp areas and starts to emerge typically around late June and early July.”

According to Deschamps, mosquitoes breed and thrive in wet and humid weather. He said it is not unusual for small ponds or other bodies of water that are placed in residential areas due to stormwater regulations to develop into a cattail swamp that attracts not only a massive spike in mosquitoes but the cattail mosquitoes.

Precautions against mosquito bites include using an insect repellent with DEET, and keeping arms and legs covered. Outside, eliminate things in which water may collect, like old tires, plastic swimming pools and children's toys. Keep woodpiles dry by keeping them covered.
Precautions against mosquito bites include using an insect repellent with DEET, and keeping arms and legs covered. Outside, eliminate things in which water may collect, like old tires, plastic swimming pools and children's toys. Keep woodpiles dry by keeping them covered.

“There is this mosquito species that develop only in cattail swamps, which unfortunately do become fairly common with stormwater regulations,” Deschamps said. “These retention ponds that are mandated and put into large areas of impervious surface are oftentimes flooded and they grow into these cattail areas. We do have larval control programs for them. However, in many cases, these areas are difficult to access for personnel.”

As of now, the Gardner area has not experienced any environmental change to the surrounding bodies of water that could spike the mosquito population or attract the cattail mosquito to the community.

Through a combination of education and control procedures, mosquito populations can be kept down in many areas, Deschamps said.

This article originally appeared on Gardner News: Spraying pesticides for mosquitoes lowers risk of West Nile and EEE