By Faith Peppers
University of Georgia
Many public health watchers predicted this to be a very active
year nationwide for West Nile Virus and other mosquito-borne
illnesses. But so far, all’s quiet on the Southern front.
“As for WNV, things have been pretty quiet up to this point,”
said Elmer Gray, a University of Georgia Extension entomologist
and a member of the Georgia West Nile Virus Task Force. “The
common thought is that we will have a similar case load as last
year (55 cases and 4 deaths).”
Many thought the area would continue to see eastern equine
encephalitis activity throughout the season, but dry weather
may have squelched this activity, Gray said. “The vectors for
EEE are swamp mosquitoes (Culiseta melanura), and I
suspect
that the swamps have less water than normal,” he said.
His suspicions are confirmed.
Dry weather a plus
“The Suwanee River coming out of the Okeefenokee Swamp has set
daily low-record flows for this time of year,” said State
Climatologist David Stooksbury. “I’m not sure what that does to
the mosquito population, but [the river] is low.”
Most would think that wet weather leads to more mosquitoes. If
standing water is left around homes following rain, that’s
true. However, it’s dry weather that brings the boom of
mosquitoes to urban areas.
“The [WNV-carrying mosquitoes] breed in storm drains of
downtown city areas,” Gray said. “When it rains, it actually
flushes out the drains. Cases of WNV or St. Louis encephalitis
actually come on after a dry spell when water has been laying
[stagnant], giving mosquitoes a chance to breed.”
Weather could aid in the fight against mosquito-borne illnesses
this year.
“The early part of this summer, rainfall has been less and
therefore less standing water is around to serve as a breeding
ground for mosquitoes,” Stooksbury added.
Plan working?
That could lessen mosquito numbers, but Gray has another
theory. The state has made great strides in improving its
ability to conduct surveillance for all mosquito-borne
diseases. And the public health field, in general, is much
better prepared and able to detect mosquito-borne viral
activity of any type.
With this in mind, Gray notes there has been very little WNV
activity detected and dead bird submissions are behind previous
years.
“We in the mosquito field would like to think that our larval
suppression programs have contributed to the lessening of WNV
activity,” he said, “but that is very difficult to measure.
Particularly since no one wants to be the control (untreated)
group that would be necessary for a legitimate study.”
Use caution
Even though the state is seeing low numbers of mosquito-borne
illnesses, it’s still important to use the proper
precautions.
“As always, it is important that people remember to try to
avoid peak periods of mosquito activity (dawn and dusk),
eliminate standing water around homes and wear insect
repellents containing DEET when in areas with mosquito
activity,” Gray cautioned. “It’s quiet now, but it’s still
early. Things could change later in the summer.”
For more information on West Nile Virus and how to avoid it,
visit the UGA College of
Agricultural and Environmental
Sciences WNV Web site.
