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SCIENTIFIC BREAKTHROUGH HELPS COMBAT TROUT DISEASE (fwd)
- Subject: SCIENTIFIC BREAKTHROUGH HELPS COMBAT TROUT DISEASE (fwd)
- From: Carol Ratza <firstname.lastname@example.org>
- Date: Mon, 27 Jan 1997 12:50:18 -0500 (EST)
---------- Forwarded message ----------
Date: Mon, 27 Jan 97 12:02:05 MST
U.S. Fish and Wildlife Service
Whirling Disease Foundation
January 13, 1997 Janet Tennyson 202-208-5634
Tom Anacker or Sue Higgins 406-585-0860
SCIENTIFIC BREAKTHROUGH HELPS COMBAT TROUT DISEASE
A major weapon in the fight against whirling disease--a trout-
killing infection that is devastating in some wild trout
populations--has been developed by researchers at the University
of California-Davis, the U.S. Fish and Wildlife Service and the
Whirling Disease Foundation announced today.
Mr. Karl Andree and Professor Ronald Hedrick at the university's
School of Veterinary Medicine isolated genes specific to the
parasite causing whirling disease, allowing scientists to apply a
special DNA-based test as a diagnostic tool. The research
leading to this advance was funded by the U.S. Fish and Wildlife
Service, the Whirling Disease Foundation, Trout Unlimited, and
the Montana Department of Fish, Wildlife, and Parks.
"This opens up a promising new era in our efforts to protect
America's prime trout fisheries from whirling disease," said John
Rogers, Acting Service Director. "It gives fishery managers an
early warning system that should enable them to detect this
disease early and help control its spread."
Whirling disease, caused by a microscopic parasite introduced to
the United States in the 1950s, is believed responsible for the
decimation of trout populations in some of America's most
renowned trout streams, especially in the Rocky Mountain West.
In recent years, whirling disease has been associated with an
estimated 90-percent decline in Montana's upper Madison River
wild rainbow trout population as well as disastrous rainbow trout
losses in Colorado's South Platte, Gunnison, and Colorado rivers.
This has alarmed scientists and anglers alike, spurring several
intensive research efforts.
Andree and Hedrick isolated genes from Myxobolus cerebralis (the
parasite causing whirling disease), allowing the use of a modern
diagnostic test known as the Polymerase Chain Reaction (PCR).
The test can also detect infections in the parasite's other host,
the aquatic worm Tubifex tubifex. The PCR test amplifies even
very small amounts of the parasite's DNA, allowing its detection
at much lower levels than previously possible.
Refining the PCR method may also allow non-lethal diagnostic
testing of trout in the future, which scientists consider
increasingly important in the face of dwindling wild trout
populations in some locations. With the new discovery, the PCR
method can also indicate the parasite's existence in a given body
According to Beth MacConnell, the Service's top whirling disease
biologist stationed at the Bozeman Fish Technology Center in
Montana, the discovery will be a crucial component of all future
whirling disease research. "The new diagnostic tool provides
speed, accuracy, and sensitivity we simply didn't have before,"
The spores of Myxobolus cerebralis, released when infected fish
die, are ingested by Tubifex worms, which live in mud. Inside
the worm, the parasite takes on a new form, becoming capable of
infecting young salmonids, especially rainbow trout, before their
cartilage hardens to bone. Myxobolus cerebralis gets into the
cartilage near a fish's organ of equilibrium and multiplies very
rapidly, sometimes into the millions, pressuring the organ and
causing the victim to swim erratically, losing its ability to
forage or to escape predators.
The new test is already being used by Professors Robert Ellis at
Colorado State University and Stuart Knapp at Montana State
University to analyze infections.
The quantitative sensitivity of the PCR tool is being measured in
Dr. Ellis' lab. The results of this work will allow fishery
managers to determine the levels of infection in streams. The
data obtained from this research will be correlated with young-
of-the-year fish surveys to determine the ratio of mortality
levels to levels of infection.
Dr. Knapp's laboratory is using the PCR method to test Tubifex
worms taken from dozens of Montana streams. Results will provide
information on the seasonality of whirling disease, which may
help scientists develop new management strategies for combatting
The whirling disease parasite has been detected in at least 21
states: California, Colorado, Connecticut, Idaho, Maryland,
Massachusetts, Michigan, Montana, Nevada, New Hampshire, New
Jersey, New Mexico, New York, Ohio, Oregon, Pennsylvania, Utah,
Virginia, Washington, West Virginia, and Wyoming.
In addition to the $200,000 the Service provided for this
research, in 1996 the agency joined the National Fish and
Wildlife Foundation; the Montana Department of Fish, Wildlife,
and Parks; and the Whirling Disease Foundation to provide a
$195,000 grant for construction of a whirling disease research
laboratory at Montana State University. A secure, contained
facility was needed to study whirling disease-infected organisms
to determine fish and worm genetic factors that promote or limit
parasite growth and investigate methods to control the disease in
infected watersheds. In addition, the Service has intensified
its research efforts to combat whirling disease at its Bozeman
Fish Technology Center.
The Whirling Disease Foundation is co-sponsoring a national
symposium on whirling disease March 6-8, 1997, in Logan, Utah.
"This symposium will provide the opportunity for the latest
research findings on whirling disease to be shared with the
research community and the public," said Dr. Karl Johnson,
Science Director of the Whirling Disease Foundation.
Presentations will include reports on the range of the infection
and distribution of the Tubifex worm, results of comparative
studies of the sensitivity of different fish species to the
disease, methods for filtering and quantifying the fish-infective
state of the parasite from water samples, and investigations into
the initial interactions between the parasite and the two hosts
included in its life cycle.
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Date: Tues, 14 Jan 1997 7:45:00 -0600 (MDT)
From: Mitch Snow <firstname.lastname@example.org>
Subject: SCIENTIFIC BREAKTHROUGH HELPS COMBAT TROUT DISEASE