[BCNnet] from January 6, 2004, Daily Herald
judymellin
judymellin@netzero.net
Wed, 7 Jan 2004 09:31:44 -0800
This is a multi-part message in MIME format.
------=_NextPart_000_016E_01C3D501.10538B20
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
West Nile 2004: In check or rebound?
By Susan Stevens=20
Daily Herald Staff Writer=20
Posted 1/6/04=20
With 4 inches of snow outside your window, you may not be thinking about =
mosquitoes right now.
But local health officials are.
In particular, they're thinking about the ones that brought a deadly =
outbreak of West Nile disease two years ago - then all but vanished last =
summer.
Entomologists suggest a variety of reasons for Illinois' dip in West =
Nile virus cases in=20
2003: cooler weather, fewer birds, more vigilant homeowners.
Or it could be luck.
"We don't know, and nobody else does," says Tom Schafer, spokesman for =
the Illinois Department of Public Health. "It could be simply that the =
virus moved west."
Whatever the reason, public health officials are thankful 2003 did not =
bring the high death toll of 2002 - when 66 Illinois residents died of =
the West Nile virus and 884 became ill.
In 2003, amid frequent warnings of a possible outbreak, Illinois saw =
only 52 cases of humans infected with West Nile and just one death.
But West Nile experts aren't rejoicing. While Illinois suffered fewer =
illnesses, nationwide the number of cases more than doubled as the =
mosquito-borne virus continued its westward expansion since its =
emergence on the East Coast in 1999.
Colorado was the heaviest hit with 2,477 human cases last year, =
according to the Centers for Disease Control and Prevention.
The unpredictability of West Nile has Illinois officials planning =
full-scale preparations for Spring 2004.
"If we have hot, dry conditions like we did in 2002, we could see a =
rebound," said Thad Koeune, director of environmental health services =
for DuPage County. "Nobody can tell you for sure."
DuPage County will increase its tracking of the virus this spring, =
beginning in May with dozens of new mosquito monitoring traps throughout =
the county.
In Kane County, officials have compiled the past two years of mosquito =
data to determine the likely hot spots in 2004.
"We always have to be vigilant and be prepared if there is a =
resurgence," said Fred Carlson, environmental health director for Kane =
County. "We're cautiously optimistic it might be another year of =
minimal activity."
In addition to their public education programs about eliminating =
stagnant water and wearing insect repellant, health officials will watch =
the weather closely this spring.
A hot, dry summer like that in 2002 could offer an ideal breeding =
environment for disease-carrying Culex mosquitoes, a species that =
colonizes stagnant pools such as catch basins.
Entomologists theorize the intermittent rains and cool temperatures of =
2003 freshened stagnant water and slowed breeding of Culex mosquitoes in =
Illinois.
Bird populations also play a role. West Nile virus felled so many crows =
and blue jays in=20
2002 some experts believe fewer birds were left to transmit the virus =
the following year.
Humans bit by infected mosquitoes might have carried some immunity to =
the virus, though the virus is too new to know how long the protection =
lasts.
West Nile hasn't been in the United States long enough to establish a =
discernible pattern, entomologists say. But they suspect it may =
eventually follow the model of other mosquito-borne diseases, such as =
the St. Louis encephalitis that broke out in Illinois in=20
1975.
That year, nearly 600 Illinois residents became ill and 47 died of the =
disease. But in=20
1976, and every year since then, the number of St. Louis encephalitis =
cases dropped to almost negligible levels.
As it happens, Illinois' climate in 1975 closely resembled the state's =
weather in 2002, when Illinois had the highest West Nile death toll in =
the nation. Precipitation and temperature for the summer months are =
identical for the two years, said Michael Szyska, an entomologist and =
director of the Northwest Mosquito Abatement District of Cook County.
"It's not surprising we had a major outbreak," Szyska said.
Under the right environmental conditions, a new virus can wreak havoc in =
a population with no resistance to the disease, Szyska said. After the =
initial infection sweeps the area, the number of cases typically drops - =
as did St. Louis encephalitis cases in 1976.
For the most part, West Nile has followed the same pattern as it moved =
west.=20
Midwestern states hit hard in 2002 posted lower numbers of infected in =
2003, when the virus beset the Rocky Mountain states.
But at least one state has bucked that trend.
In Pennsylvania, where West Nile first emerged in 2000, the number of =
cases nearly quadrupled in 2003 over the previous year.
"Maybe because it's a new virus, West Nile hasn't settled in yet," =
Szyska said. "It's a very chaotic system and hard to predict."
------=_NextPart_000_016E_01C3D501.10538B20
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2800.1276" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV>West Nile 2004: In check or rebound?<BR></DIV>
<DIV>By Susan Stevens </DIV>
<DIV>Daily Herald Staff Writer </DIV>
<DIV>Posted 1/6/04 </DIV>
<DIV> </DIV>
<DIV>With 4 inches of snow outside your window, you may not be thinking =
about=20
mosquitoes right now.</DIV>
<DIV> </DIV>
<DIV>But local health officials are.</DIV>
<DIV> </DIV>
<DIV>In particular, they're thinking about the ones that brought a =
deadly=20
outbreak of West Nile disease two years ago - then all but vanished last =
summer.</DIV>
<DIV> </DIV>
<DIV>Entomologists suggest a variety of reasons for Illinois' dip in =
West Nile=20
virus cases in <BR>2003: cooler weather, fewer birds, more vigilant=20
homeowners.</DIV>
<DIV> </DIV>
<DIV>Or it could be luck.</DIV>
<DIV> </DIV>
<DIV>"We don't know, and nobody else does," says Tom Schafer, spokesman =
for the=20
Illinois Department of Public Health. "It could be simply that the =
virus=20
moved west."</DIV>
<DIV> </DIV>
<DIV>Whatever the reason, public health officials are thankful 2003 did =
not=20
bring the high death toll of 2002 - when 66 Illinois residents died of =
the West=20
Nile virus and 884 became ill.</DIV>
<DIV> </DIV>
<DIV>In 2003, amid frequent warnings of a possible outbreak, Illinois =
saw only=20
52 cases of humans infected with West Nile and just one death.</DIV>
<DIV> </DIV>
<DIV>But West Nile experts aren't rejoicing. While Illinois =
suffered fewer=20
illnesses, nationwide the number of cases more than doubled as the=20
mosquito-borne virus continued its westward expansion since its =
emergence on the=20
East Coast in 1999.</DIV>
<DIV> </DIV>
<DIV>Colorado was the heaviest hit with 2,477 human cases last year, =
according=20
to the Centers for Disease Control and Prevention.</DIV>
<DIV> </DIV>
<DIV>The unpredictability of West Nile has Illinois officials planning=20
full-scale preparations for Spring 2004.</DIV>
<DIV> </DIV>
<DIV>"If we have hot, dry conditions like we did in 2002, we could see a =
rebound," said Thad Koeune, director of environmental health services =
for DuPage=20
County. "Nobody can tell you for sure."</DIV>
<DIV> </DIV>
<DIV>DuPage County will increase its tracking of the virus this spring,=20
beginning in May with dozens of new mosquito monitoring traps throughout =
the=20
county.</DIV>
<DIV> </DIV>
<DIV>In Kane County, officials have compiled the past two years of =
mosquito data=20
to determine the likely hot spots in 2004.</DIV>
<DIV> </DIV>
<DIV>"We always have to be vigilant and be prepared if there is a =
resurgence,"=20
said Fred Carlson, environmental health director for Kane County. =
"We're=20
cautiously optimistic it might be another year of minimal =
activity."</DIV>
<DIV> </DIV>
<DIV>In addition to their public education programs about eliminating =
stagnant=20
water and wearing insect repellant, health officials will watch the =
weather=20
closely this spring.</DIV>
<DIV> </DIV>
<DIV>A hot, dry summer like that in 2002 could offer an ideal breeding=20
environment for disease-carrying Culex mosquitoes, a species that =
colonizes=20
stagnant pools such as catch basins.</DIV>
<DIV> </DIV>
<DIV>Entomologists theorize the intermittent rains and cool temperatures =
of 2003=20
freshened stagnant water and slowed breeding of Culex mosquitoes in=20
Illinois.</DIV>
<DIV> </DIV>
<DIV>Bird populations also play a role. West Nile virus felled so =
many=20
crows and blue jays in <BR>2002 some experts believe fewer birds were =
left to=20
transmit the virus the following year.</DIV>
<DIV> </DIV>
<DIV>Humans bit by infected mosquitoes might have carried some immunity =
to the=20
virus, though the virus is too new to know how long the protection =
lasts.</DIV>
<DIV> </DIV>
<DIV>West Nile hasn't been in the United States long enough to establish =
a=20
discernible pattern, entomologists say. But they suspect it may =
eventually=20
follow the model of other mosquito-borne diseases, such as the St. =
Louis=20
encephalitis that broke out in Illinois in <BR>1975.</DIV>
<DIV> </DIV>
<DIV>That year, nearly 600 Illinois residents became ill and 47 died of =
the=20
disease. But in <BR>1976, and every year since then, the number of =
St. Louis encephalitis cases dropped to almost negligible =
levels.</DIV>
<DIV> </DIV>
<DIV>As it happens, Illinois' climate in 1975 closely resembled the =
state's=20
weather in 2002, when Illinois had the highest West Nile death toll in =
the=20
nation. Precipitation and temperature for the summer months are =
identical=20
for the two years, said Michael Szyska, an entomologist and director of =
the=20
Northwest Mosquito Abatement District of Cook County.</DIV>
<DIV> </DIV>
<DIV>"It's not surprising we had a major outbreak," Szyska said.</DIV>
<DIV> </DIV>
<DIV>Under the right environmental conditions, a new virus can wreak =
havoc in a=20
population with no resistance to the disease, Szyska said. After =
the=20
initial infection sweeps the area, the number of cases typically drops - =
as did=20
St. Louis encephalitis cases in 1976.</DIV>
<DIV> </DIV>
<DIV>For the most part, West Nile has followed the same pattern as it =
moved=20
west. <BR>Midwestern states hit hard in 2002 posted lower numbers of =
infected in=20
2003, when the virus beset the Rocky Mountain states.</DIV>
<DIV> </DIV>
<DIV>But at least one state has bucked that trend.</DIV>
<DIV> </DIV>
<DIV>In Pennsylvania, where West Nile first emerged in 2000, the number =
of cases=20
nearly quadrupled in 2003 over the previous year.</DIV>
<DIV> </DIV>
<DIV>"Maybe because it's a new virus, West Nile hasn't settled in yet," =
Szyska=20
said. "It's a very chaotic system and hard to predict."</DIV>
<DIV> </DIV>
<DIV> </DIV></BODY></HTML>
------=_NextPart_000_016E_01C3D501.10538B20--