Monday, June 25, 2012

West Nile Virus Positive Mosquitoes Identified In 20 Connecticut Towns

Twenty Connecticut towns are reported to have West Nile Virus positive mosquitoes, Department of Public Health Commissioner Dr. J. Robert Galvin informs. Connecticut's Mosquito Management Program announced that a resident of Clinton recently tested positive for WNV (West Nile Virus) and has been admitted to hospital.

The elderly resident showed symptoms of fever, severe headache, weakness and fatigue during the first month of September and is in hospital for meningitis. Laboratory tests confirmed the presence of WNV antibodies.

Six people have been reported with WNV infection in the state so far this year, the other five are from Bridgeport, Greenwich, New Haven, Stamford and Trumbull. Health authorities say two more individuals who travelled out of state also became infected.

Dr. Galvin said:

West Nile virus can cause serious illness, especially in people over 50. In Connecticut, this is the time of year when the risk of getting sick from West Nile virus is the greatest. West Nile virus is transmitted by mosquitoes, and simple things like wearing long-sleeved shirts, using insect repellant, and minimizing time outside at dusk and dawn when mosquitoes are most active can help you reduce your risk of getting this virus.


The 20 towns where WNV-positive mosquitoes have been identified include Bethel, Bridgeport, Darien, Fairfield, Greenwich, Manchester, Meriden, Milford, Newtown, Norwalk, New Britain, New Haven, Orange, Stamford, Stratford, Trumbull, Wallingford, West Haven, Westport and Wethersfield.

Dr. Theodore G. Andreadis, Ph.D., Chief Medical Entomologist, The Connecticut Agricultural Experiment Station, said:

Although cooler weather is expected which should slow virus build-up, we continue to repeatedly identify infected mosquitoes throughout central and southern regions of the state. We anticipate that virus activity will continue for several more weeks.


The Connecticut Agricultural Experiment Station says it has a network of 91 mosquito-trapping stations in 72 municipalities throughout the state, operating from June till the end of October. The traps are set every ten days at each site on a rotating basis. The mosquitoes are pooled according to collection site, date and species. Each pool is tested for West Nile Virus and eastern equine encephalitis viruses.

What is West Nile Virus?

West Nile Virus, or WNV, is a virus of the Flaviviridae family which is spread by the bite of an infected mosquito. The Flaviviridae virus family also includes dengue fever, Japanese encephalitis, and yellow fever.

WNV affects birds mainly, but horses, dogs, cats, bats, skunks, squirrels, chipmunks and domestic rabbits may also become infected, as well as humans.

In most cases, an infected human either has no signs or symptoms at all, or just a skin rash and headache. About 1% of infected individuals, unfortunately, develop complications such as encephalitis (inflammation of the brain), myelitis (inflammation of the spinal cord), or meningitis (inflammation of tissues surrounding the brain and spinal cord), which are potentially life-threatening.

People with weakened immune systems as well as elderly individuals have a higher risk of developing complications.

West Nile Virus (WNV) is found in both tropical and temperate regions. WNV outbreaks occur in Egypt, Israel, Pakistan, France, the northern Mediterranean and some parts of Eastern Europe. In 1996 there was a major outbreak in Budapest, Hungary. In 1999 it appeared in New York and has since been found in all 48 US contiguous states. More recently it has been found in Canada, Mexico, Central America and the West Indies.

According to the National Health Service (NHS), UK, the WNV spread in mainland Europe and North America has made many experts fear that it is only a question of time before it reaches the United Kingdom. So far, there has only been one reported case in the UK - a tourist who arrived home after becoming infected while on vacation in Portugal.

People in areas known to have infected mosquitoes can reduce their risk of infection by using mosquito repellent, wearing clothing that covers most of their skin, and taking some other preventive measures.

According to the CDC (Centers for Disease Control and Prevention), USA, over 15,000 people in the United States have tested positive for WNV since 1999 - over 500 of them have died. Authorities say the real number of infected people is much higher, because those with either no symptoms or very mild ones would not have sought medical help.

A bird-mosquito life cycle maintains West Nile virus in the environment. According to the U.S. Geological Survey's National Wildlife Health Center, American crows (Corvus brachyrhynchos) and other corvids (e.g., blue jays) seem more susceptible to fatal infection - nobody knows why. The death of these birds has allowed many local health departments to utilize dead birds as an indicator of the virus emergence or re-emergence in their areas.

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