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mosquitoes

    MOSQUITOES

    West Nile Virus Makes Its Annual Appearance Here

    Experts recommend removing standing water to control the disease

    By

    EASTHAM — West Nile virus, a mosquito-borne illness that appears on Cape Cod annually, has been detected in a sample of the insects in the Fort Hill area of Eastham. The disease, which was also identified in a mosquito sample from West Barnstable, appears among Cape Cod’s mosquitoes in midsummer and fall.

    Dave Self of the Cape Cod Mosquito Control Project applies Bacillus thuringiensis (Bti) larvicide on the stagnant water at Head of the Meadow in Truro, where mosquitoes normally breed. (Photo by Nancy Bloom)

    “Almost every summer since it came into Massachusetts, we’ve found mosquitoes that were positive for West Nile virus,” said entomologist Gabrielle Sakolsky, superintendent of the Cape Cod Mosquito Control Project, the quasi-governmental agency that detected the virus in Eastham.

    The project maintains 20 mosquito traps distributed across Cape Cod; seven of them are on the Outer Cape. The Eastham sample that contained West Nile virus was collected on Aug. 24 and consisted of 10 mosquitoes. Because the samples are measured as a batch, it is unknown how many of those mosquitoes were carrying the disease.

    The Mosquito Control Project also monitors for the Eastern equine encephalitis (EEE) virus, which has not been detected on Cape Cod at all this year. The Mass. Dept. of Public Health has assessed the risk of EEE on the Outer Cape as “remote” — the lowest possible level of risk.

    West Nile virus infects thousands of Americans annually. It was first identified in the U.S. in 1999 and spread to Cape Cod in 2003. From 2011 to 2020, 148 cases of the virus were identified in people in Massachusetts. Seven of those cases, or 5 percent, were lethal.

    “I wouldn’t spend a lot of time being anxious about West Nile virus, but it’s very appropriate to take some steps to prevent mosquito bites,” said Catherine Brown, an epidemiologist with the Mass. DPH. The state agency currently lists the risk of West Nile virus on the Outer Cape as “low,” and Brown said that this year has seen fewer cases than usual in the state compared to most years.

    But, Sakolsky said, “It doesn’t mean there’s no risk.”

    West Nile virus is usually first detected here by the Mosquito Control Project’s monitoring program starting in July. As the summer goes on, the virus becomes more common in mosquito populations. Later in the season, even though there may be fewer mosquitoes, they are more likely to be carrying the disease, said Sakolsky.

    Most West Nile virus infections are not dangerous. According to the Centers for Disease Control, only 20 percent of people infected with the virus develop symptoms. They are usually flu-like: fever, chills, headaches, and vomiting. Less than 1 percent of those infected develop serious symptoms like meningitis and brain inflammation. Among those infected, the chances of dying are around 1 in 1,500, though they are higher among people over 60 and those with medical conditions like cancer, diabetes, or hypertension.

    The disease is primarily transmitted by birds and mosquitoes. When the virus first reached the U.S., it was detected among a flock of American crows in Queens, N.Y. Some mammals can contract the disease as well. Besides humans, horses, dogs, and cats have been infected with it, though the latter two animals rarely show any symptoms at all.

    The best way to mitigate the spread of West Nile virus is through mosquito population control. And since mosquitoes need standing water to reproduce, and eggs can develop into adults in as little as a week, the Mosquito Control Project works to lower the number of insects by removing sources of standing water. If the sources cannot be removed — say, in wetland areas — they use larvicide to make the water inhospitable to developing mosquitoes.

    This process uses bacteria known as Bti and Bacillus sphaericus, which break down cells in the larvae’s digestive system, killing the mosquitoes. These bacteria affect only mosquitoes and their fly relatives, leaving other insects, fish, birds, and mammals unharmed. If mosquito larvae are too developed to be killed by the bacteria, Mosquito Control will instead drop mineral oil into the water to kill them.

    To stop the proliferation of mosquitoes, Sakolsky said, “go around your yard after rain, dump out all that standing water, and you won’t be raising these mosquitoes on your property.” Her organization recommends draining sources of water around the house, such as clogged roof gutters, buckets, tires, and birdbaths, to prevent mosquitoes from laying their eggs. It also recommends stocking ornamental ponds with koi or goldfish to eat mosquito larvae and ensuring that swimming pools are well filtered, as chlorine alone will not keep pools mosquito-free.

    Both Brown and Sakolsky said that the larvicide is a more effective mechanism of mosquito control than spraying yards to kill adult mosquitoes. Using conventional spraying mechanisms “is a very temporary approach,” said Sakolsky, whereas controlling standing water and deploying larvicide is the more “permanent solution.”

    To keep yourself safe from West Nile virus, public health experts recommend wearing mosquito repellent with an EPA label on it. These will contain approved active ingredients such as DEET, permethrin, picaridin, IR3535, or lemon eucalyptus oil. As temperatures cool, the DPH also recommends wearing long-sleeved tops and long pants when outdoors to minimize bites.

    “It’s just a good idea to take steps to prevent getting bitten by mosquitoes,” said Brown. “Even if you’re not in a hotspot.”

    “It’s never good to be bitten by a mosquito,” said Sakolsky. “It’s like ticks: you don’t know what they’re carrying.”

    OUT OF CONTROL

    Mosquito Population Stays High Despite Treatment

    Itchy residents turn to private companies for relief

    By

    WELLFLEET — One month after the Cape Cod Mosquito Control Project began treating breeding areas in the Herring River basin, this year’s proliferating plague of mosquitos is proving more difficult to squash than expected. With the larvicide approach off to a late start and working slowly, home owners are turning to private spraying — something experts say should be undertaken with caution and low expectations of success.

    When it comes to mosquito control, “larvicide is how to do it properly,” said Larry Dapsis, an entomologist who works for Barnstable County. “In terms of day-to-day relief, spraying for the adults is not a rational solution.” That’s partly because mosquitos can fly long distances, he said — up to 10 miles for certain types. Even if spraying kills what’s in your yard now, more mosquitos will soon arrive from beyond your immediate surroundings.

    Curt Felix, owner of the Wellfleet franchise of Cape Cod Mosquito Squad, said that the company offers two mosquito treatment plans: an “all-natural cedar product” and a traditional chemical treatment.

    Cedarwood oil is considered a minimum-risk pesticide by the EPA, meaning that it is not regulated at the state level. Minimum-risk pesticides are thought to pose little risk to humans and the environment.

    Felix said that the cedar treatment used by Mosquito Squad has been in testing for three years and is “comparable” in effectiveness to the traditional treatment. Dapsis disagreed, saying research shows that natural oil-derived treatments are “completely ineffective” at deterring mosquitos.

    Felix would not say what is in the traditional chemical treatment, but according to Chris Miller, a Wellfleet resident who hired Mosquito Squad to treat his yard, the company informed him that permethrin, a standard insecticide, was used.

    Dave Sullivan in action for his Cape Cod Mosquito Mary’s franchise. (Photo Nancy Bloom)

    Mark Faherty, science coordinator at Mass. Audubon’s Wellfleet Bay Wildlife Sanctuary, said he worries about the effects of sprayed treatments on other insects that are important for the local ecosystem, such as bees and butterflies. Permethrin is toxic to both if it comes in contact with them, Faherty said, while research shows that mosquito larvicide has no effect on pollinators.

    Felix said that the treatments Mosquito Squad uses are EPA-approved and that customers do not see a reduction in pollinators in their yards after treatment. “There’s a theoretical risk, but people are not seeing it,” he said.

    Geoff Sanders, chief of natural resource management and science for the Cape Cod National Seashore, said that the park has no policy on what private citizens do on their property. “I’m not really in a position to say whether that’s good or bad,” he said.

    Felix said the Mosquito Squad applies its treatments to foliage. Permethrin is not water soluble, according to Dapsis, meaning it will not run off into the water table when it rains. He said the chemical breaks down naturally in a matter of weeks.

    Dapsis said that insecticide spraying can be done “quite safely, as long as the applicator is following the rules.” In practice, that means preventing fogging from drifting away from one yard into neighboring areas. But, he added, he never recommends that home owners spray their yards for mosquitos.

    The use of pesticides like permethrin is regulated by the Mass. Dept. of Agricultural Resources (MDAR). There are rules applicators have to follow, such as avoiding drift and minimizing human contact with the spray.

    While some residents have embraced yard treatment, others grimace at the idea. Buddy Paine, who lives in Wellfleet, is not a fan. He said he’s seen fogging done on a neighbor’s property drift into his yard, and he showed the Independent a video of a cloud of spray wafting onto his property. He said he has reported the incident to the MDAR.

    “We’re trying to do the right thing and really be careful” when spraying, Felix said.

    Entomologist Gabby Sakolsky, superintendent of Mosquito Control, the quasi-governmental organization charged with managing mosquito populations on the Cape, said larvicide treatment in the brackish areas, where the insects are breeding, has not yet reduced their populations.

    As has been previously reported, Mosquito Control got a late start on the larvicide treatments because it had to wait for special permission from the National Park Service.

    Now progress is slow because crews are finding that overgrown vegetation is making it hard to reach some pools of water where mosquitos are laying eggs. Sakolsky said she is in conversation with the Seashore about clearing paths through the brush to access different pools of standing water.

    Depending on what’s needed, that, too, could take some time. “There are some things we can approve fairly easily,” said Sanders. But for clearing larger plants, he said, further review will be required.

    Sanders also said the overwash at Duck Harbor in Wellfleet that initially brought salt water into the river basin — and provided new real estate for mosquitos to lay eggs in — has continued since the larvicide treatment began.

    Despite these new challenges, Sakolsky is hopeful that there will be a noticeable drop in the number of mosquitos in the next several weeks.

    The rise in private yard spraying shows the importance of a long-term arrangement between Mosquito Control and the Seashore, Dapsis said. The special permit that has allowed Mosquito Control to treat in the Herring River basin extends through December 2021. Sakolsky and Sanders both said they are optimistic that there will be a longer-term arrangement between the Park and Mosquito Control.

    Both the Seashore and Mosquito Control want to be “proactive rather than reactive,” Sanders said. “But we need to agree on what leads to treatment.” Sanders predicted that “more focused conversations” will happen in late August.

    CLIMATE CRISIS

    This Summer, We’ll Be Feeling More Than Just the Heat

    Cyanobacteria blooms and mosquito booms expected to rise, too

    By

    PROVINCETOWN — In the face of climate change and humans’ apparent inability to forestall what is becoming an increasingly irreversible disaster, drink water.

    Also, you’ll need to use more bug spray. Maybe don’t go into that pond. You know the one: the one that had the algal bloom last year.

    Speaking of which, check your septic system. Get it pumped out. Actually, install a new septic system. One of the new high-tech ones. Try not to be old. Old people don’t do well in the heat. Plan your outdoor time for the morning hours. And when the afternoon heat does roll around, you’re going to need to start chugging that water again.

    That’s the advice offered by local authorities in a range of fields — scientists, landscapers, and a social worker — on coping with the effects of hotter summers.

    According to the National Oceanic and Atmospheric Administration, the average maximum temperature in Boston in May this year was 2.1 degrees Fahrenheit higher than the average for the past 50 years. Mark Adams, an ecologist at the Cape Cod National Seashore and a Provincetown local, explained that, although that doesn’t sound like a lot, those two degrees are significant.

    “If there’s even a one-degree change in average temperature, that means there may be days when there’s an extreme change,” Adams said. “Those extreme temperatures can be unsafe for many people.”

    “The heat is a concern, because older people’s internal thermometers are not as good,” said Suzanne Grout Thomas, director of the Wellfleet Council on Aging. “And many older people don’t like to drink water because that means they have to make extra trips to the bathroom.” It’s important to do so, though, she added, because “dehydration in times of heat can create real emergencies.”

    Thomas said the council on aging’s monthly newsletter, available only online, will, this summer, feature “a whole section about hydrating and not going out in the heat of the day.”

    Thomas recalled one “spectacularly hot summer” when the town’s Senior Center was open as a cooling station. “You could come and read a book and be in the cool for a few hours and by evening, when you went home, maybe your house was less oppressive,” she said.

    Such solutions may become more common, though Grout Thomas noted that in recent years many people have installed air conditioning — “especially those nifty split units that you just turn on and off with a remote control.” Those units usually run about $1,000, not including installation.

    Gunter Leirer, a landscaper in Provincetown, also says heat and hydration are top of mind for him.

    “We start early in the morning — as early as we can,” he said. “We quit if it gets too hot. I’m the first one to leave. And I drink lots of water.”

    Climate change is changing Leirer’s view of what should be planted on local landscapes. Native plants are a wise choice, he said, because they are already accustomed to sandy soil, which tends to be quite dry and hot.

    Wellfleet landscaper Kai Potter (who writes about the local landscape in the Independent) said he has also been planting an increasing number of natives. Among those he recommends are “native grasses like little or big bluestem, viburnums, sweet fern, bayberry, or a nice ornamental like yarrow.”

    Potter lives a double life in a way. His two identities — plantsman and surfer — present him with a dilemma when it comes to assessing the impact of rising temperatures and sea levels. As a caretaker of the land, “I have a self who doesn’t want there to be huge storms ravaging various parts of the world,” he said. “But, as a surfer, if we’re getting more weather, I love that.” That’s because “bigger storms equals bigger waves.”

    The Association to Preserve Cape Cod continues its tracking of cyanobacteria blooms. In this image, a bloom on Upper Mill Pond in Brewster. (Photo courtesy APCC)

    Kevin Johnson is an ecologist and the overseer of the cyanobacteria program at the Association to Preserve Cape Cod. He explains that cyanobacteria are extraordinarily common in fresh water. And at normal concentrations, they present no cause for concern for humans. In fact, in low concentrations, they might even be beneficial: “You have cyanobacteria to thank for our oxygen-rich atmosphere, since they’re the first photosynthesizers,” he said.

    The problem is when they start to exist in abundance. Cyanobacteria produce toxins that are “damaging or fatal to humans and wildlife,” said Johnson. “When a pond is loaded with nutrients already, and then you combine that with warm temperatures, toxins start to bloom.”

    While cyanobacteria blooms are more common up Cape, Gull Pond in Wellfleet was closed in July 2019 due to a cyanobacteria bloom. It was the first time a Wellfleet pond had closed for such a reason. The bloom was the product of phosphorus deposits (fossil fuel burning is the culprit in that case) in the pond and the increasing temperature of the water.

    Replacing cesspools is part of the solution to removing excess nutrients from the water. And even if you have an up-to-date septic system, Johnson recommends having it pumped out regularly.

    Gabrielle Sakolsky, a scientist who runs the Cape Cod Mosquito Control Project, explained that there are 25 species of mosquitoes on Cape Cod. Most are freshwater species. There are not many of those around yet, because the weather has been quite dry, she said. But the reason you might be scratching mosquito bites already is because of the heat-induced proliferation of the saltwater species.

    “Heat helps move them along the life cycle more quickly,” Sakolsky said. She recommends wearing bug spray and stopping the use of sprinklers on yards, which can lead to water gathering in road drains or gaps in the grass.

    Use that water, instead, for drinking.

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