Aerial mosquito spraying done as state urges continued caution

Posted 9/11/19

By ETHAN HARTLEY Public health officials are warning residents that the buzz around Eastern Equine Encephalitis and West Nile Virus is not simply being drummed up or exaggerated - and they've taken to the skies to prove it. It's definitely not a media"

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Aerial mosquito spraying done as state urges continued caution


Public health officials are warning residents that the buzz around Eastern Equine Encephalitis and West Nile Virus is not simply being drummed up or exaggerated – and they’ve taken to the skies to prove it.

“It’s definitely not a media phenomenon,” said Joseph Wendelken, public information officer for the Rhode Island Department of Health. “[We’re experiencing] a higher than average risk in Southern New England when it comes to mosquito-borne illnesses.”

On Sunday and Monday, the state conducted aerial mosquito treatment spraying in four areas of Rhode Island considered to be at “critical risk” for the life-threatening EEE. One of those areas included all of West Warwick along with parts of Cranston, Warwick and other communities.

Then, on Monday, the health department confirmed that a person who was confirmed in August to have contracted EEE in West Warwick died on Sunday. The person, who officials said was over 50 years of age, is the first person to die of EEE in Rhode Island since 2007. A horse in Westerly tested positive for the disease on Aug. 29.

The latest developments came after the health department and the Rhode Island Department of Environmental Management announced last week that a second mosquito carrying EEE was trapped at a testing location at Chapman Swamp in Westerly. Another site in Tiverton contained the first mosquito in Rhode Island to test positive for West Nile Virus.

To date, that marks four EEE-positive mosquitoes from two separate mosquito species tested in traps in Rhode Island – two in Central Falls and two in Westerly, which demonstrates the possible range of the illness.

In addition to the positive testing in Rhode Island, there have been four human cases already diagnosed in Massachusetts and others found in Connecticut.

According to a statement from DEM, the pesticide used in the aerial spraying, Anvil 10, was “used in very low concentrations” and “no adverse health risks are expected with its use for mosquito control.”

“Spraying will not occur over fish hatcheries, certified organic farms, surface drinking water supplies, and other open water bodies and coastal areas,” the statement reads. “Massachusetts officials used the same product in recent aerial spraying in Bristol, Plymouth, Worcester, and other counties. Anvil is registered by the US Environmental Protection Agency and in Rhode Island and Massachusetts for this use.”

In addition to the West Warwick area, the spraying was conducted in all or part of Coventry, East Greenwich, West Greenwich, Central Falls, Pawtucket, North Providence, Providence, East Providence, Smithfield, North Smithfield, Lincoln, Cumberland, Burrillville, Woonsocket, Westerly, Hopkinton, and Charlestown.

In response to the uptick in mosquito-related illness activity and with input from entomologists at the University of Rhode Island, DEM has added 10 new traps in five new communities, making for a total of 38 trapping locations in 23 Rhode Island municipalities. New traps have been set in West Warwick, West Greenwich, Burrillville, North Smithfield and Cumberland – areas that border “high risk” areas in Connecticut and Massachusetts.

“Typically, DEM sets between 25 and 30 traps in Westerly, Charlestown, South Kingstown, North Kingstown, Exeter, Warwick, Cranston, Johnston, Providence, Central Falls, Pawtucket, East Providence, Barrington, Warren, Bristol, Tiverton, Portsmouth, and Newport,” a joint DEM and RIDOH press release from last week reads. “By increasing trapping and tracking mosquito species, volume, and infection, the state is working to assess the risk of further human disease.”

There is no vaccine to protect against EEE and no medical treatment available to fight the illness once it is contracted. The disease can cause swelling of the brain and proves fatal in an average of 30 percent of cases, according to the Centers for Disease Control and Prevention. Symptoms include a sudden onset, headache, high fever, chills and vomiting, which can progress into seizures and coma.

“EEE is a very serious illness but it’s also on the rarer side,” Wendelken said, adding that in an average year, there are about seven diagnoses of EEE in the entire country.

“All we can do is provide supportive care,” Wendelken added in terms of what should happen if you are experiencing symptoms believed to be associated with a mosquito illness. “The sooner that someone gets in contact with a healthcare provider and gets some of those symptoms treated, the better. But it’s a very serious illness. Even when people are getting treatment, the mortality rate is still very high.”

The best way to avoid contracting either EEE or West Nile is by taking preventative steps to avoid being bitten by mosquitoes. DEM and RIDOH have released a long list of recommendations, including:

Protect yourself

  • Put screens on windows and doors. Fix screens that are loose or have holes.
  • At sunrise and sundown (when mosquitoes that carry EEE and WNV are most active), consider rescheduling outdoor activities that occur during evening or early morning. If you must be outside, wear long-sleeved shirts and long pants and use bug spray.
  • Use EPA-approved bug spray with one of the following active ingredients: DEET (20-30 percent strength); picaridin, IR3535; and oil of lemon eucalyptus or paramenthane. Always read the label and follow all directions and precautions.
  • If you plan to hike in the woods in daylight, it is advisable to wear repellent to prevent being bitten by daytime mosquitoes.
  • Do not use bug spray with DEET on infants under two months of age. Children should be careful not to rub their eyes after bug spray has been applied on their skin. Wash children’s hands with soap and water to remove any bug spray when they return indoors.
  • Put mosquito netting over playpens and baby carriages.

Get rid of mosquito breeding grounds

  • Get rid of anything around your house and yard that collects water. Just one cup of water can produce hundreds of mosquitoes; an unused tire containing water can produce thousands of mosquitoes.
  • Clean your gutters and downspouts so that they can drain properly.
  • Remove any water from unused swimming pools, wading pools, boats, planters, trash and recycling bins, tires, and anything else that collects water, and cover them.
  • Remove or treat any shallow water that can accumulate on top of a pool cover. Larvicide treatments, such as Mosquito Dunks can be applied to kill immature mosquitoes. This environmentally-friendly product is available at many hardware and garden stores and on-line.
  • Change the water in birdbaths at least two times a week and rinse out birdbaths once a week.

They also include best practices for horse owners, who are particularly susceptible to the diseases. They advise horse owners to vaccinate their animals early in the season and practice the following:

  • Remove or cover areas where standing water can collect.
  • Avoid putting animals outside at dawn, dusk, or during the night when mosquitoes are most active.
  • Insect-proof facilities where possible and use approved repellents frequently.
  • Monitor animals for symptoms of fever and/or neurological signs (such as stumbling, moodiness, loss of appetite) and report all suspicious cases to a veterinarian immediately. If you are unsure if your horse is properly vaccinated, you should consult with your veterinarian. Wendelken cautioned residents that there is no boundary within Rhode Island for mosquito illnesses, and that everyone should take the same precautions.

“Those measures that people should be taking in Westerly they should also be taking in Providence and Central Falls and Newport and every other city and town,” he said.

The state has continued to recommend school districts and municipalities reschedule sporting activities and other events that would take place during early morning or dusk hours, when mosquitoes are most active.

“The ‘smart scheduling’ of events is intended to help minimize the risk of mosquito bites for players, coaches, and spectators,” the release states. “RIDOH recommends that smart scheduling stay in effect for the remainder of the mosquito season, which typically ends in mid-October (after the first hard frost).”

Visit for additional mosquito prevention tips, videos and local data.

Daniel Kittredge contributed to this report.


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