Heading toward high season for mosquito-borne diseases
The Rhode Island Department of
Environmental Management (DEM) and Rhode Island Department of Health (RIDOH)
today announce the fifth detection of West Nile Virus (WNV) in a mosquito
sample collected in the state this summer.
The additional mosquito sample testing
positive for WNV was collected in Cranston on Aug. 21. As announced earlier this week, the first detection
of Eastern Equine Encephalitis virus (EEE) in Rhode Island in 2023 came from a
mosquito sample collected in Glocester and the state’s fourth WNV detection
came from a mosquito sample collected in Barrington. Overall, DEM collected 195
samples of mosquitoes from 25 traps set statewide on Aug. 21. All other samples
tested negative for WNV and EEE.
To date, the Commonwealth of Massachusetts has
announced 96 WNV findings, and the State of Connecticut reports 67
WNV findings. WNV and EEE findings in mosquitoes are expected
because mosquito-borne diseases become more prevalent in Southern New England
as the season progresses. To date, Massachusetts has confirmed two humans
cases of WNV and Connecticut has confirmed one human
case of WNV.
Although extremely rare in humans, EEE is very serious and has a much higher human mortality rate than WNV. Approximately 30% of people with EEE die and many survivors have ongoing neurological problems. Unlike WNV, which is prevalent in Rhode Island every year, EEE risk is variable, changing from year to year.
With continued
trapping and testing, DEM and RIDOH will be able to assess the EEE risk level
this mosquito season. Neither Massachusetts nor Connecticut has reported any
findings of EEE in mosquitoes, humans, or animals. For more information on
EEE and ways to prevent it, please visit www.health.ri.gov/eee.
WNV is the leading cause of mosquito-borne disease in the continental United States and is much more prevalent than EEE. Cases of WNV occur during mosquito season, which starts in the summer and continues through fall. There are no vaccines to prevent or medications to treat WNV in people.
Fortunately, most people infected with WNV do not feel
sick. About one in five people who are infected develop a fever and other
symptoms. About one out of 150 infected people develop a serious, sometimes
fatal, illness. For more information on WNV and ways to prevent it, please
visit www.health.ri.gov/wnv.
DEM and RIDOH advise Rhode Islanders to reduce their exposure to mosquitoes
until the first hard frost. (A hard frost is when the air and the ground
freeze below 32°F for three hours or below 28°F for two hours.) Personal
protection is the first line of defense against mosquitoes that may carry WNV,
EEE, or other diseases – and the most effective way to avoid infection. The
following precautions are advised.
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 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% strength), picaridin, IR3535,
and oil of lemon eucalyptus or paramenthane. Always read the label and follow
all directions and precautions.
Do not use bug spray with DEET on infants
under two months of age. Check the product label to find the concentration of
DEET in a product. The American Academy of Pediatrics recommends that
repellents should contain no more than 30% DEET when used on children. 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.
Remove mosquito breeding grounds
Remove items around your house and yard
that collect 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 online.
Clean and change water in birdbaths at
least once a week.
Best practices for horse owners
Horses are particularly susceptible to WNV
and EEE. Horse owners are advised 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.
Visit health.ri.gov/mosquito for additional
mosquito prevention tips, videos, and local data. Mosquitoes are trapped weekly
by DEM and tested at the RIDOH State Health Laboratories. DEM issues
advisories on test results from June through September, with additional
reports as necessary. Typically, positive test results trigger additional
trapping to assess risk.
For more information on DEM programs and
initiatives, visit www.dem.ri.gov. Follow DEM on Facebook, Twitter (@RhodeIslandDEM), or
Instagram (@rhodeisland.dem) for timely updates.