HomeMy WebLinkAboutE-News-City Publications-8/1/2014NEWS
Sample site tests positive for fourth time
The Tarrant County Public Health Department (TCPHD) has notified the city of
Colleyville that a mosquito from one of its regular sample sites has tested
positive for the West Nile Virus (WMV). This positive test came from the same
site where a mosquito in each of three previous samples tested positive. The
mosquitoes were collected in an area near Windview Estates, in the southeast
section of the city.
The city has escalated its treatment program at this site by introducing a granular
larvacide (Vectolex FG) to achieve greater coverage in the creek area where the affected
mosquitoes hatch. City staff will conduct mosquito surveillance in the area daily and
continue to treat as necessary. The city is in contact with the neighborhood HOA and will
work with them until the issue is resolved.
The site will be retested in a week, in accordance with mosquito management protocol.
Those results will be posted on Colleyville.com, as soon as they are available. This site
will continue to be tested on a weekly basis until the end of mosquito season.
Q&A
Why doesn't the city just spray? That would take care of the problem.
Frankly, the easiest route for the city would be to implement ground spraying. However,
it's not our best option to actually take care of the problem at this location. Ground
spraying only kills the mosquitoes hit by the spray. It's unlikely a mosquito in someone's
backyard would be killed by spraying conducted from a truck driving down the street,
much less in a creek or tributary (the likely source site) running behind homes in the
area.
Mapping the positive tests in Colleyville and those in neighboring cities, shows that the
affected mosquitoes are originating from the same small creek or tributary running
through the area. (View a map of positive results in the area.) The problem seems
to be localized to this creek bed. It is heavily wooded with a substantial amount of
foliage-the perfect breeding ground for mosquitoes. Spraying from the street, or even
aerial spraying, likely would not reach the areas identified as the most likely source of
the infected mosquitoes. These areas are located in the creek bed in pools of stagnant
water, beneath the foliage. Spraying from outside or above this heavy foliage would
likely not filter down to the area that needs to be treated.
Will the city ever spray for mosquitoes?
Our mosquito management protocol calls for spraying in the event of a positive human
case of the West Nile Virus. However, like our citizens, we are extremely concerned
about multiple positive tests at one site. We have not ruled out spraying if the Vectolex
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FG product doesn't work; however, even if we elect to start spraying in this area, it is
still unlikely that we will use a spraying truck. It is more likely that we will spray only in
the creek bed (or other affected area, should the need arise), using a UTV or backpack,
so that we increase our chances of eliminating the problem at its source.
This is the fourth positive at the same location. Doesn't that mean the city's
larvacide program isn't working-at least not at this site?
The goal of the larvicide program is prevent mosquito larvae from reaching adulthood
and to decrease the mosquito population in the area. By that measure, the larvicide
program is working. It keeps mosquito larvae from reaching adulthood. In the past
week mosquitoes caught in the sample trap at this site decreased by about two-thirds-
from 182 to 65.
Spraying does achieve the same result-a reduction in the mosquito population;
however, for older people, young children, and those with impaired respiratory function,
spraying can have serious consequences. In fact, a young child in another Tarrant
County city was taken to the hospital as a direct result of spraying in the area. That city
has now suspended their spraying program and is using larvicide as a preventative
measure.
In addition, with larvicide-whether the larvicide briquettes the city has been using or the
granular product (Vectolex FG) we're implementing now-there is a residual effect. These
products continue to kill mosquito larvae for weeks and months after treatment. There
is no residual effect with spraying.
Why hasn't the city been more aggressive in treating for mosquitoes?
The city has an aggressive mosquito management program in place that has been
effective in most areas. This particular area has been treated repeatedly with larvicide
briquettes. City crews have been walking the creek bed multiple times a week for the
last few weeks, trying to locate the mosquito source and using the briquettes in
suspected areas. That activity will now take place every day in an intense effort to find
and treat the problem, this time with Vectolex FG, a granular larvicide. The simple fact
is that no matter what method we use to treat the mosquito population, it will not be
effective unless we locate the source. Every effort is being made to do that...and those
efforts will continue. Read about Vectolex.
What makes Vectolex more effective?
This is a granular larvicide that provides greater coverage in areas suspected of housing
mosquito larvae. Like sugar, Vectolex is granulated so it spreads out, increasing the
opportunity for larvae to ingest it. It poses no danger to people, pets, birds, bees,
beneficial insects, or wild animals-it only kills mosquito and fly larvae.
How does larvicide kill mosquitoes?
Larvicides are eaten by mosquito larvae, causing damage to the gut cells and quickly
paralyzing the larvae and killing them quickly and efficiently.
Why doesn't the city use Vectolex at all its testing sites?
The current program, using larvicide briquettes, has proven effective in most areas. The
city has had one other site near Sparger Park that tested positive for one sample this
year. Crews immediately started an aggressive treatment program using larvicide
briquettes. Since that time, in early July, all mosquitoes at that site have tested
negative for the West Nile Virus.
Why doesn't the city follow Tarrant County's protocol and spray any time a
positive sample is identified?
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At one time, the city's mosquito management protocol and Tarrant County's were the
same. Then the county moved to a protocol that involved more frequent spraying. While
spraying does help decrease the mosquito population, it might be considered a shotgun
approach because it also kills beneficial insects and bees, and can pose a health risk to
some people.
The city, using an aggressive larvicide program, has chosen a more targeted method. It
doesn't have the immediate impact; however, it has been proven effective and longer
lasting, and it carries less risk to people, pets, and nature.
What's next?
The city has already starting treating the area with Vectolex FG and will conduct daily
surveillance and treatment of any areas containing mosquito larvae. Mosquitoes trapped
at the site will be collected and submitted to Tarrant County for testing. The city is
notified about any positive test results each Wednesday and those results will be posted
to the city's website, Colleyville.com, and sent out through the city's e-news service and
the city Facebook page. If there is a positive result, residents within a ¼-mile radius will
be alerted through the CodeRED call system.
Staff members have been in contact with the Windview Estates HOA to make them
aware of everything the city is doing to combat mosquitoes in their area and to address
their questions or concerns. We will continue to keep them posted on the results of our
efforts and, if further escalation in the treatment process is warranted, the city will work
with the HOA for their protection and to best address the problem.
The city will also continue to test sample sites located throughout Colleyville and will
work to address any mosquito issues that may arise during mosquito season, which
typically runs from May 1 through October. (While mosquito season officially starts on
May 1, the city's mosquito management protocol for treatment and testing starts on
April 1.)
Colleyville Mosquito Control & Management
West Nile Virus FAQs
GENERAL
Summer reading program grand finale - Friday, Aug. 1
The summer reading grand finale happens tonight from 5:30 to 8:30 p.m. in front of the
library. Everyone is invited to enjoy a live deejay, children's arts and crafts, face
painting, balloons, carnival games, bounce houses, plus a "trackless" rain, inflatable zip
line, and two water slides. Bring a swimsuit and towel for the water slides, and plan to
cool off with a few refreshments (for a minimal cost) from Market Street and Texas Ice
Cream. The event is free and open to all ages. See you at the library!
Citizen boards and commissions - applications being accepted through
Friday, Aug. 29
Those who serve on city boards, commissions, or committees make a difference in the
decisions that affect Colleyville. The City Council is accepting applications through Aug.
29, for positions on the following citizen boards, commissions, and committees:
•Historical Preservation Committee
•Library Board
•Metroport Teen Court Advisory Board
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•Planning and Zoning Commission
•Senior Center Advisory Board
•Zoning Board of Adjustment
Access an application form here. Completed forms should be sent to
ashelley@colleyville.com, faxed to 817.503.1139, or mailed to:
City of Colleyville
City Secretary
100 Main Street
Colleyville, Texas 76034
For more information, call 817.503.1130.
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