Greenwich Mosquitoes Test Positive for West Nile Virus [Update]

Updated 9:05 a.m.:

The mosquitoes that tested positive for West Nile Virus were taken from a state mosquito trap located in Old Greenwich near the Eastern Greenwich Civic Center.

Greenwich Director of Environmental Health Michael Long said the town is continuing its larvicide spraying in catch basins. A private contractor is paid about $7,000 to apply the larvicide every 4 to 6 weeks and will continue to do so through the end of September, depending upon the weather, Long said.

The second round of larvicide was applied last week, according to Long. Weather factors into the number of applications made each season, but generally three to four are done annually, he added.

"It was the common mosquito" that was found to be carrying the virus, Long said. He urged residents to check gutters, buckets left outdoors, bird baths and even tree stumps which become breeding grounds if water is left standing for more than 4 to 5 days.

The state will continue its testing every one to two weeks throughout the season, which lasts until there is an extended period of 50-degree temperatures, Long said. The other mosquito traps are located in the Mianus River Park and on Lake Avenue in the backcountry, Long said.

Until the mosquito season ends, Long suggests residents use bug repellent and wear long sleeves to ward off the biting pests.

Original story:

The Town of Greenwich Health Department and the State of Connecticut Mosquito Management Program announced late Tuesday that mosquitoes trapped in Greenwich in mid-July 2011 have tested positive for West Nile Virus (WNV).

A message seeking additional information including where the mosquitoes were captured, was not immediately returned.

Here is the announcement posted by the town health department.

These are the first positive mosquitoes identified by the Connecticut Agriculture Experiment Station (CAES) in Greenwich this year.  In addition to Greenwich, WNV positive mosquito pools have been found in 2 other towns in Connecticut - Orange and Bridgeport. The mosquitoes trapped are generally bird and mammal biting which breed in artificial containers like discarded tires, birdbaths and catchbasins.

So far this year no Connecticut residents have been identified with WNV related illnesses. The State Mosquito Management Program continues to trap and test mosquitoes at three locations in Greenwich as part of their program, which maintains a network of 91 mosquito-trapping stations in 72 municipalities throughout the State. The trapping program continues through October 2011.

The Town of Greenwich continues the fight against West Nile Virus by conducting a preemptive larviciding program, which includes the treatment of public and private roadway catch basins, public school ground catch basins and other property owned and operated by the Town as needed.

This year’s program began in June and larvicide is reapplied every four to six weeks. Director of Health, Caroline Calderone Baisley stated, “Controlling the mosquito population in the larval stage through the application of larvicide has been found to be a prudent action. Although this measure helps reduce the mosquito population, it certainly does not eliminate it. Residents are encouraged to protect themselves.”

The town, along with several state agencies, will implement an integrated mosquito management program that includes monitoring and surveillance, education and prevention. Adult mosquito control will only be considered if necessary. Baisley said, “Although the town’s larvicide program treats catch basins, the general public must be vigilant in eliminating standing water on their own properties and protecting themselves from biting mosquitoes at all times. It is important to recognize that the highest risk of exposure to West Nile Virus infected mosquitoes is during the months of August and September.” 

In monitoring for the virus, the state Department of Public Health will be responsible for the surveillance of West Nile Virus infection in humans; and the Connecticut Department of Agriculture (DoAg) will carry out surveillance in domestic animals. Though bird testing is no longer being conducted by the State of Connecticut residents are encouraged to report dead birds, such as crows, bluejays and ravens, to the Division of Environmental Services at 203-987-1001.   Once reported, birds may be wrapped in a plastic bag and discarded in the trash. Residents are encouraged not to handle the birds directly with their hands.

When bitten by an infected mosquito, most people are able to fight off the infection and experience either mild symptoms, such as headache and fever, or no symptoms at all. It is believed that approximately one in 100 persons bitten by an infected mosquito become ill. In a minority of infected persons, especially those over 50 years old, West Nile Virus can cause serious illness, including encephalitis and meningitis.  Infection leads to death in 3 to 15 percent of persons with severe forms of the illness.

The virus is spread to humans by the bite of an infected mosquito, which becomes infected when it bites a bird carrying the virus.  West Nile virus is not spread by person-to-person contact or directly from birds to people. Although there is no specific treatment or cure, the symptoms and complications of the disease can often be treated.  Most people who become ill recover.

In some individuals, including the elderly and persons with compromised immune systems, WNV can cause serious illness that affects the central nervous system. At its most serious, it can cause permanent neurological damage and can be fatal. General symptoms occur suddenly between 5 – 15 days following the bite of an infected mosquito and range from a slight fever, headache, rash, swollen lymph nodes, nausea, malaise and eye pain, to the rapid onset of severe headache, high fever, stiff neck, disorientation, severe muscle weakness, gastrointestinal symptoms, coma or death.

Residents are encouraged to see a physician immediately if they develop any of these sudden symptoms.

“The finding of WNV positive mosquitoes helps to emphasize the fact that personal measures are extremely important to protect ourselves against biting mosquitoes during the day and at night,” said Michael Long, director of Environmental Services.

The following precautions should be taken:

• Avoid outdoor activities at dawn and dusk when mosquitoes are most active.
• If you plan to be outdoors for a long period of time, wear long sleeved shirts, long pants and use mosquito repellent according to the manufacturer’s directions on the label (10% or less DEET for children and no more than 30% DEET for adults). Always wash treated skin when returning indoors. Avoid application of repellents with DEET on infants and small children.
• Cover up arms and legs of children playing outdoors and cover playpens or carriages with mosquito netting.
• Don’t camp overnight near stagnant or standing water where mosquitoes are most active.

In addition, Greenwich residents are urged to continue to participate in the Town’s mosquito control efforts by eliminating areas of standing water around their homes which includes:

Yard and Home Checklist

•  Get rid of old tires, tin cans, buckets, drums, bottles or any water holding containers.
•  Fill in or drain any low places (puddles, ruts) in yard.
•  Keep rain gutters, drains, ditches and culverts clean of weeds and trash so water will drain properly.
•  Cover trash containers to keep out rainwater.
•  Repair leaky pipes and outside faucets.
•  Empty plastic wading pools at least once a week and store indoors when not in use.
•  Make sure your backyard pool is properly chlorinated every day.
•  Fill in tree rot holes and hollow stumps that hold water with sand or concrete.
•  Change the water in birdbaths and plant pots or drip trays at least once each week.
•  Keep grass cut short and shrubbery well trimmed around the house so adult mosquitoes cannot hide there.
•  Eliminate collected water in boat or pool covers.

Ponds and stagnant water bodies that do not support fish, frogs or other amphibians that eat mosquito larvae may be treated with a biological control agent such as Bacillus thuringiensis israelensis (BTI).  It is suggested that the Department of Health or Conservation be contacted when treatment is considered.

For more information about the Greenwich larviciding program, personal protection and property management recommendations, the State of Connecticut mosquito management program, the following contact sites are available. 

The Town of Greenwich Mosquito Management Brochure is available throughout the community and on the town’s website www.greenwichct.org or by calling the department's Division of Environmental Services at 203-987-1001, or the Greenwich Conservation Commission 203-622-6461.