Connecticut Department of Energy & Environmental Protection

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08/02/2018

Gov. Malloy and Public Health Officials Advise Residents of Increased West Nile Virus Activity this Season

Governor Dannel P. Malloy and state public health officials are advising Connecticut residents to be aware of a rapid build-up of West Nile virus (WNV) activity within the state as recent tests show that infected mosquitoes are rising at levels higher than normal for this time of year.  The Connecticut Agricultural Experiment Station (CAES) has detected WNV-infected mosquitoes in 19 municipalities this year, including Bethany, Bridgeport, Darien, East Haven, Easton, Franklin, Greenwich, Hartford, Madison, Manchester, Meriden, New Canaan, New Haven, Stamford, Stratford, Waterbury, Waterford, West Haven, and Weston.
“Based on the data we have so far this season, we know that cases of infected mosquitoes are rising at levels that are higher than normal, and that’s why it is essential for people to take extra precautions,” Governor Malloy said.  “If you need to be outside – and especially if you work outside – take action to protect yourself and your family.”
“We are detecting more West Nile virus-infected mosquitoes, including those that readily feed on humans, than is typical for this time of year,” Dr. Philip Armstrong, Medical Entomologist at the CAES, said.  “These conditions lead to an increased risk of human infection that will likely continue from now until the end of September.”
“We fully anticipate further build-up of the virus in the coming weeks and expansion into other areas of the state,” Dr. Theodore Andreadis, Director of CAES, said.  “The current warm weather and high humidity are providing ideal conditions for mosquitoes and intensification of West Nile virus.  Historically, August and September are the months of greatest risk for acquiring West Nile virus infection.”
“We are very concerned by the amount of West Nile virus we are seeing at this point in the summer season, and we urge the people of Connecticut to take the threat posed by mosquitoes that carry the virus seriously,” Department of Public Health Commissioner Dr. Raul Pino said.  “In addition to wearing long clothes, using mosquito repellant and taking other precautions to avoid mosquito bites, everyone can help to control our mosquito populations by eliminating standing water around your home and in your neighborhoods.  It takes only a small amount of standing water – in a bird bath, in an old car tire, in overturned lids, in empty pots, anywhere – to provide a breeding ground for mosquitoes.”
“Connecticut has some great natural spaces, from state parks, to state forests and wildlife management areas,” Department of Energy and Environmental Protection Commissioner Rob Klee said. “We urge those who are recreating outdoors to take common sense steps to prevent bug bites, including the use of mosquito repellents, along with wearing long pants and long-sleeved shirts.”
No human or horse cases have been reported with WNV-associated illnesses acquired in Connecticut this season.  One hundred thirty four human cases of WNV, including three fatalities, have been diagnosed in Connecticut residents since 2000.
Tips for reducing mosquitoes around homes
Mosquitoes require water for reproduction. The following are measures that can help reduce mosquitoes:
  • Elimination of standing water suitable for mosquitoes Dispose of water-holding containers, such as ceramic pots, used tires, and tire swings.
  • Drill holes in the bottom of containers such as those used for recycling.
  • Clean clogged roof gutters.
  • Turn over objects that may trap water when not in use, such as wading pools and wheelbarrows.
  • Change water in bird baths on a weekly basis.
  • Clean and chlorinate swimming pools. When pools are not in use, use pool covers and drain when necessary.
Tips for avoiding mosquito bites when outdoors
Mosquitoes require a blood meal for reproduction.  The following are measures that can help reduce bites from mosquitoes that feed on people:
  • Be particularly careful at dusk and dawn when mosquitoes are most active.
  • Wear shoes, socks, long pants, and long-sleeved shirts. Clothing material should be tightly woven.
  • Use mosquito netting when sleeping outdoors.
  • Consider the use of CDC- recommended mosquito repellents, containing DEET, picaridin, oil of lemon eucalyptus, IR3535, or 2-undecanone, and apply according to directions, when it is necessary to be outdoors.
  • When using DEET, use the lowest concentration effective for the time spent outdoors (for example, 6 percent lasts approximately two hours and 20 percent for four hours) and wash treated skin when returning indoors.  Do not apply under clothing, to wounds or irritated skin, the hands of children, or to infants less than two months old.
  • Also, be sure door and window screens are tight fitting and in good repair to avoid mosquito bites when indoors.
Figure 1.  Connecticut towns in which WNV-infected mosquitoes have been detected in 2018
Connecticut towns in which WNV-infected mosquitoes have been detected in 2018
Figure 2.  Weekly number of WNV-positive mosquito pools detected in 2018 compared to 12-year average
Weekly number of WNV-positive mosquito pools detected in 2018 compared to 12-year average
The State of Connecticut Mosquito Management Program is a collaborative effort involving the Department of Energy and Environmental Protection, the Connecticut Agricultural Experiment Station, the Department of Public Health, the Department of Agriculture, and the University of Connecticut Department of Pathobiology and Veterinary Science.  These agencies are responsible for monitoring the potential public health threat of mosquito-borne diseases.
The CAES maintains a network of 91 mosquito-trapping stations in 72 municipalities throughout the state.  Mosquito traps are set Monday to Thursday nights at each site every ten days on a rotating basis.  Mosquitoes are grouped (pooled) for testing according to species, collection site, and date.  Positive findings are reported to local health departments and on the CAES website at https://www.ct.gov/caes/mosquitotesting.
For information on West Nile and eastern equine encephalitis viruses and how to prevent mosquito bites, visit the Connecticut Mosquito Management Program Web site at www.ct.gov/mosquito.

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