Study shows giardia
present in central
and southern Illinois waterways
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A recent study funded by the
Federal Aid in Wildlife Restoration Program determined the presence
of Giardia intestinalis in beavers in five watersheds in central and
southern Illinois. Giardia cysts can be transmitted to humans who
ingest contaminated water, causing severe intestinal disorders that
are sometimes called "beaver fever" by hikers and other
According to an article published in
the Transactions of the Illinois State Academy of Science
("Prevalence of Giardia intestinalis in Illinois Beavers." McNew,
L.B., Jr., T.A. Nelson, and S.T. McTaggart. 2003. TISAS 96:113-118),
Giardia cysts were detected in 30.8 percent of 107 beavers tested.
This exceeded infection rates reported by past studies in the United
States and Canada.
The authors concluded, "Whether beavers
serve as initial sources of surface water contamination or as
amplifying hosts, this intestinal parasite is likely to become more
prevalent in Illinois' waterways as beaver populations increase
Illinois' annual beaver trapping
season, the primary means of managing the beaver population in the
state, is Nov. 5, 2003, to March 31, 2004, in the north zone and
Nov. 10, 2003, to March 31, 2004, in the south zone.
information on trapping regulations, contact the IDNR's wildlife
program development office, at (217) 782-6384.
[From an Illinois
Department of Natural Resources