Emily
Editor, Senior Moderator
http://www.yale.edu/yibs/YEN%20Spring%202007.pdf
Ultrasonic Frogs: New Technology Used
to Track Animal Disease through History
Yale Peabody Museum of Natural History curator and professor of
ecology David Skelly has teamed up with doctoral student Manja
Holland and research technician Susan Bolden to investigate the use
of ultrasound in studying disease.
The group learned in November 2006 that
they had been awarded a $250,000 National
Science Foundation grant to purchase a recently
developed ultrasound system. Unlike typical
systems, the new ultrasound machine from
Canadian manufacturer VisualSonics is capable
of discerning objects as small as 0.03 millimeter.
This extremely high resolution opens up
new possibilities for ultrasound analysis. The
researchers plan to use it to uncover patterns
of infection hidden inside frogs.
History of Illness
This work will be part of a larger effort to
uncover the history of disease. Reports of disease
among both people and wildlife seem to
be increasing. This sense has led scientists to
ask whether there is a historical trend for the
increasing incidence of disease and whether
such a pattern may be related to changes to
the environment caused by humans. While
seemingly straightforward, such questions
are difficult to answer. New diseases are discovered
each year and our ability to diagnose
infection tends to improve over time. The best
information about trends will come from systems
where the same disease can be examined
within a sample of ?patients? that are distributed
over time, but still available for diagnosis.
This study will focus on a group of parasites
called echinostomes. Echinostomes form cysts
in the kidneys and can number in the hundreds
in highly infected animals. Recent research by
Professor Skelly?s laboratory at Yale has shown
that infections can become severe, particularly
in ponds in landscapes altered by human activity.
In some cases, animals harboring the parasites
undergo kidney failure and can die from
infection and its aftermath. Holland?s dissertation
research examines why this happens and
how severe the effects can be.
Treasure Trove
Thus far, research on echinostome infection
has concentrated on modern patterns. Frogs
preserved in museum collections provide a
potential treasure trove of information, but
there are challenges. Older specimens are irreplaceable;
destroying them to remove and dissect
the kidneys is typically not an option. Even
if done with a few specimens, researchers are
unlikely to get a picture of an overall pattern.
Dissecting is also extremely time consuming. A
single specimen may take an entire day.
Ultrasound investigation avoids these
issues. Scanning is rapid and does not harm
the specimen. The trick is fi guring out how
to apply the technology effectively. At a physician?s
offi ce, the casual observer marvels at the
ability of the technician to make out objects in
an ultrasound image of a developing fetus that
seem thoroughly abstract. This ability is the
result of intense training. Ultrasound analysis
used for research is no different. The research
team began working with its new machine at
the end of December and after one training
session there is much more work ahead. Once
profi cient at scanning specimens and turning
images into estimates of infection, they will
move on to the Yale Peabody Museum?s herpetology
collection in the Division of Vertebrate
Zoology, where Skelly serves as curator. The
Peabody?s rich historical holdings will be a critical
proving ground for the use of specimens
that may have been collected more than a century
ago.
Ultrasonic Frogs: New Technology Used
to Track Animal Disease through History
Yale Peabody Museum of Natural History curator and professor of
ecology David Skelly has teamed up with doctoral student Manja
Holland and research technician Susan Bolden to investigate the use
of ultrasound in studying disease.
The group learned in November 2006 that
they had been awarded a $250,000 National
Science Foundation grant to purchase a recently
developed ultrasound system. Unlike typical
systems, the new ultrasound machine from
Canadian manufacturer VisualSonics is capable
of discerning objects as small as 0.03 millimeter.
This extremely high resolution opens up
new possibilities for ultrasound analysis. The
researchers plan to use it to uncover patterns
of infection hidden inside frogs.
History of Illness
This work will be part of a larger effort to
uncover the history of disease. Reports of disease
among both people and wildlife seem to
be increasing. This sense has led scientists to
ask whether there is a historical trend for the
increasing incidence of disease and whether
such a pattern may be related to changes to
the environment caused by humans. While
seemingly straightforward, such questions
are difficult to answer. New diseases are discovered
each year and our ability to diagnose
infection tends to improve over time. The best
information about trends will come from systems
where the same disease can be examined
within a sample of ?patients? that are distributed
over time, but still available for diagnosis.
This study will focus on a group of parasites
called echinostomes. Echinostomes form cysts
in the kidneys and can number in the hundreds
in highly infected animals. Recent research by
Professor Skelly?s laboratory at Yale has shown
that infections can become severe, particularly
in ponds in landscapes altered by human activity.
In some cases, animals harboring the parasites
undergo kidney failure and can die from
infection and its aftermath. Holland?s dissertation
research examines why this happens and
how severe the effects can be.
Treasure Trove
Thus far, research on echinostome infection
has concentrated on modern patterns. Frogs
preserved in museum collections provide a
potential treasure trove of information, but
there are challenges. Older specimens are irreplaceable;
destroying them to remove and dissect
the kidneys is typically not an option. Even
if done with a few specimens, researchers are
unlikely to get a picture of an overall pattern.
Dissecting is also extremely time consuming. A
single specimen may take an entire day.
Ultrasound investigation avoids these
issues. Scanning is rapid and does not harm
the specimen. The trick is fi guring out how
to apply the technology effectively. At a physician?s
offi ce, the casual observer marvels at the
ability of the technician to make out objects in
an ultrasound image of a developing fetus that
seem thoroughly abstract. This ability is the
result of intense training. Ultrasound analysis
used for research is no different. The research
team began working with its new machine at
the end of December and after one training
session there is much more work ahead. Once
profi cient at scanning specimens and turning
images into estimates of infection, they will
move on to the Yale Peabody Museum?s herpetology
collection in the Division of Vertebrate
Zoology, where Skelly serves as curator. The
Peabody?s rich historical holdings will be a critical
proving ground for the use of specimens
that may have been collected more than a century
ago.