Second Colorado Case of West Nile Virus Confirmed
July 2, 2007, DENVER - State health
officials Monday confirmed a second human case of West Nile
virus involving an individual from Cheyenne County. The
first case was reported last week in an individual from
Logan County.
John Pape, an epidemiologist who
specializes in animal-related diseases at the Colorado
Department of Public Health and Environment, explained,
"West Nile virus season is here, and we expect numbers to
escalate very rapidly in the next few weeks. Because of
confirmed cases and rapidly rising mosquito numbers, now is
the time to take precautions against West Nile virus, which
is a preventable disease.
"West Nile virus can be avoided by
eliminating mosquito breeding grounds in back yards, wearing
insect repellent and using other methods to avoid mosquito
bites when outdoors," he said.
The announcement of the second human case
of West Nile follows confirmation of the first mosquito
pools that tested positive for West Nile in Larimer County
last week. In addition, several counties have reported that
populations of Culex mosquitoes, which transmit West Nile
virus, are extremely high for this time of year and are
rising.
Pape said, "Each season this virus will be
present and circulating around the state. The severity of
the season will depend on the weather."
Pape said studies show that cool, wet
weather in early spring followed by very hot temperatures
throughout the summer, which has been the weather pattern in
Colorado so far this year, can be associated with a bad
year. "Although only three mosquito pools have tested
positive so far, this will change very quickly," he said.
In reviewing statewide surveillance data
over the past four seasons, Pape said patterns of human
infections have emerged. "Approximately 85 percent of
people who became ill with West Nile virus from 2003 to 2006
were infected when bitten by an infected mosquito during a
six-week period from July 1 through the second week of
August. Therefore, we are entering the peak season of West
Nile virus transmission," explained Pape.
Infected mosquitoes continue to feed
through September and early October, depending on the
weather, but fewer than 10 percent of human cases are
contracted after Labor Day, Pape explained. "July and
August are the highest-risk months of being infected, and
people should be extra diligent during this time and use
whatever methods available to avoid mosquito bites. This is
particularly important one hour before sunset through around
midnight, when Culex mosquitoes are most actively feeding,"
he said.
Pape said that individuals can reduce the
number of mosquitoes by cleaning out gutters and other
places around their homes where there are pools of standing
water that are good breeding places for mosquitoes. Such
breeding grounds include empty flowerpots, plastic swimming
pools or old tires.
"If you have a birdbath, remember to
change the water at least weekly.
This also is a good time to repair torn window and door
screens," he
said.
Additional precautions to take against
West Nile virus include the following:
Use precautions or avoid outdoor
activities, such as gardening, at dawn and after dusk when
mosquitoes are most active.
If outside at dawn or after dusk, cover up
by wearing light, loose-fitting pants and long-sleeved
shirts, shoes and socks.
Use approved mosquito repellents
containing DEET, picaridin or oil of lemon eucalyptus. DEET
products generally provide the longest protection times. The
other repellents do work but must be applied more
frequently. Follow the product label for correct use.
Products with 10 percent or less DEET are recommended for
children.
Colorado has experienced four full seasons
of West Nile virus transmission, each with different levels
of transmission. In 2006, there were 345 cases reported
with seven deaths. The mildest year thus far was 2005, when
Colorado had 106 human cases and two deaths. In 2004, cases
were moderate with a total of 291 human cases, including
four deaths. This represented a sharp downturn from the
first full season of West Nile virus in Colorado in 2003
when there were 2,947 confirmed human cases of the disease
and 63 deaths. Only 14 cases were reported in 2002, when the
virus was first detected in the state in August of that
year. Overall, Colorado has recorded 3,704 human cases and
76 deaths, although the total number of identified cases
represents only a small proportion of persons who actually
were infected and became ill during this time.
Pape advised anyone who finds a dead bird
to call the Colorado Health Emergency Line for the Public (CoHELP)
at 1-877-462-2911. The emergency line staff is available to
respond to hotline calls from 7 a.m. to 11 p.m. on Mondays
through Fridays and from 9:30 a.m. to 8 p.m. on Saturdays
and Sundays. In addition to taking reports of dead bird,
staff can answer most questions about West Nile virus. The
Rocky Mountain Poison and Drug Control Center operates the
hotline under contract with the Department of Public Health
and Environment's Emergency Preparedness and Response
Program.
Additional information about West Nile
virus is available online at www.FightTheBiteColorado.com. Top of Page
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