Source: Charles Tseng (219)989-2403
Leslie Dorworth (219)989-2726
Contact: Irene Miles
Extension
Communications Specialist
(217)333-8055;
miles@uiuc.edu
E.coli DNA Fingerprinting May Lead to Fewer Beach Closings
After a cold and wet spring, it is finally time to get to the
serious
business of going to the beach. However, water
contamination, which happens
with some frequency during
the summer along the southern Lake Michigan
shoreline,
can lead to beach closings and cancelled plans.
Illinois-Indiana Sea Grant (IISG) scientists are using the
precision of DNA
fingerprinting to pinpoint sources of
E.coli that can lead to water
contamination and beach
closings. In Lake Michigan, high levels of E.coli
are
the main cause of area beach closures during the summer.
By knowing the exact source of the outbreaks, municipalities can
direct
their prevention efforts where they may be most
effective. This knowledge
may also help local officials
as they assess the risk of an outbreak. New
thinking
holds that wildlife bacteria is less of a health threat to people
than bacteria from other humans.
Charles Tseng and Evert Ting, biologists at Purdue University
Calumet, have
tracked the specific host species from
over 500 E.coli samples.
"These E.coli DNA fingerprints of known sources will be used to
determine
the source of E.coli from environmental
samples. To date, DNA fingerprints
of over 600 insolates
from beach sand and lake water have been prepared,"
said
Tseng. "The goal is to create a comprehensive E.coli database that will
eventually have over 1,000 samples."
E.coli is a bacterium found in the digestive tract of humans,
farm animals,
birds and
other
wildlife animals. When the bacterium is detected in water in
significant numbers it indicates fecal contamination. While E.coli itself
is
harmless in most cases, its presence indicates that
more harmful bacteria
are also likely to be present in
the water.
"Children, senior citizens and those who have weakened immune
systems are
most at risk from these bacteria," said
Leslie Dorworth, IISG aquatic
ecology specialist, at
Purdue University Calumet, who is also IISG's
representative on the E.coli Interagency Task Force, and its outreach
chair.
"High E.coli counts are frequently caused by overflowing
storm-water and
sewage systems. Sewage treatment
plants often do not have sufficient
capacity to retain
and process excess water from heavy rains," explained
Dorworth.
But, she added, many times we have beach closings when there is
little rain.
In these cases, contamination may come from
any number of sources, including
failed septic systems,
marinas or wildlife in or near the water.
"Municipalities have only so much money to spend on
prevention. It helps to
know where it will do the
most good," said Dorworth.
For educators and concerned organizations, IISG and the E.coli
Task Force
have created a series of posters that provide
clear and concise information
about a range of beach and
water quality issues, such as How does E.coli get
into
the lake?, along with ideas to help protect the lake. They can be
accessed on the IISG Web site at http://www.iisgcp.org/beachwatch. To order
the set of 16 posters, call Irene Miles at 217-333-8055.
Postcard-sized
copies of several of the series are also
available.
IISG has also developed water quality fact sheets that can be
ordered online
at http://www.iisgcp.org/pubs/wq/fsht.htm.
-30--
The Illinois-Indiana Sea Grant College Program is one of 30
National Sea
Grant College Programs. Created by
Congress in 1966, Sea Grant combines
university,
government, business and industry expertise to address coastal
and Great Lakes needs. Funding is provided by the National
Oceanic
Atmospheric Administration (NOAA), U. S.
Department of Commerce, Purdue
University at West
Lafayette, Indiana, and the University of Illinois at
Urbana-Champaign.
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