Mosquitoes in town test positive for West Nile virus

Mosquitoes trapped in Mianus River Park on July 18 have tested positive for West Nile virus (WNV) according to the town.

This is the first case in town this year of a positive test being found through the state of Connecticut’s Mosquito Management Program and the the Connecticut Agriculture Experiment Station (CAES) also found positive mosquito pools in Norwalk.

According to a press release from the town’s Health Department, the mosquitoes trapped are generally bird and mammal biting which breed in standing water often found in artificial containers like discarded tires, birdbaths and catch basins. So far this year no one in either Greenwich or the state has been identified as having a WNV related illness. Of the 21 human cases, diagnosed with West Nile Virus in 2012, two were Greenwich residents.

The state’s mosquito management program will continue to trap and test mosquitoes at three testing sites in Greenwich as part of their program through October.

In the meantime, the town says it is continuing its fight against West Nile virus by conducting a pre-emptive 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.

“Controlling the mosquito population in the larval stage through the application of larvicide has been found to be a prudent action,” town Director of Health Caroline Calderone Baisley said. “However, this measure only helps to reduce the mosquito population, not eliminate it. The recent warm weather and frequent rain events have increased the ability for mosquitoes to breed. Residents are encouraged to protect themselves whenever they are outdoors.”

The town’s environmental supervisor, Robert Farfaglia, added, “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.”

Peak period

The town stressed in the press realease that August and September are when risk is at its peak.

It is important to recognize that the highest risk of exposure to West Nile virus infected mosquitoes is during August and September.

The virus (WNV) is spread to humans by the bite of an infected mosquito, which becomes infected when it bites a bird carrying the virus. WNV is not spread by person-to-person contact or directly from birds to people.

General symptoms occur suddenly between five to 15 days following the bite of an infected mosquito and range from 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.

Most people who are bitten by an infected mosquito are able to fight off infection and experience mild or no symptoms at all. For some individuals, including the elderly and persons with compromised immune systems, WNV can cause serious illness that affects the central nervous system. In a minority of infected persons, especially those over 50-years-old, WNV can cause serious illness, including encephalitis and meningitis. Infection can lead to death in 3 to 15% of persons with severe forms of the illness.

“The finding of WNV positive mosquitoes in Greenwich marks the time to emphasize that personal protection measures are extremely important against biting mosquitoes during the day and at night,” Ms. Baisley said

The Department of Health recommends a number of precautions be taken to prevent contraction of WNV. Residents should avoid outdoor activities at dawn and dusk when mosquitoes are most active; wear long-sleeved shirts, long pants and use mosquito repellent if outdoors for extended periods of time; avoid camping overnight near stagnant or standing water; and, if disposing of a dead animal, handling it with gloves or a bag without touching the animal.

Additionally, Greenwich residents are urged to continue to participate in the town’s mosquito control efforts by eliminating areas of standing water around their homes.

This includes getting rid of old tires, tin cans, buckets, drums, bottles or any water-holding containers; keeping rain gutters, drains, ditches and culverts clean of weeds and trash so water will drain properly; covering trash containers to keep out rainwater; making sure your swimming pool is properly chlorinated every day; changing the water in birdbaths and plant pots or drip trays at least once each week; keeping grass cut short and shrubbery well trimmed; and eliminating collected water in boat or pool covers.

For more information about the town’s larviciding program, personal protection and property management recommendations or the state’s mosquito management program, visit

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