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- Posted Tuesday July 15, 2014
TGen-led international study finds likely origin of virulent lung fungus invading Pacific Northwest
<em>Cryptococcus gattii</em> evolving as it spreads to temperate climates
FLAGSTAFF, Ariz. - July 15, 2014 -
Cryptococcus gattii, a virulent fungus that has invaded
the Pacific Northwest is highly adaptive and warrants global
"public health vigilance," according to a study by an international
team led by the Translational Genomics Research Institute
(TGen).
C. gattii, which likely originated in Brazil, is
responsible for dozens of deaths in recent years since it was first
found in 1999 on Vancouver Island, British Columbia, Canada, well
outside its usual tropical habitats.
"We identified several genes that may make the outbreak strains
more capable of surviving colder environments and that make it more
harmful in the lungs," said David Engelthaler, Director of Programs
and Operations for TGen's Pathogen Genomics Division (TGen North)
and lead author of the study published today in the scientific
journal mBio.
This study should form the basis of additional investigations
about how and why C. gattii disperses and emerges. It
identified several new genomic targets for diagnostic tests, and
possible new targets for therapeutic drugs and preventative
vaccines.
"By closely analyzing the genomes of dozens of outbreak strains,
as well as globally diverse strains, we were able to closely
compare and determine the genomic differences that may cause their
clinical and ecological changes," said Dr. Paul Keim, one of the
study's senior authors. Dr. Keim also is Director of TGen North,
and Director of the Microbial Genetics and Genomics Center at
Northern Arizona University (NAU).
TGen, working with the U.S. Centers for Disease Control and
Prevention and others, conducted one of the largest global fungal
genome analyses of a specific species to understand its emergence
in new environments. The collaborative team included 24 researchers
from 13 institutions in seven nations who sequenced 115 genomes of
C. gattii collected from 15 countries.
"By thinking globally, we were able to better understand what was
happening locally," Engelthaler said.
C. gattii was typically a tropical fungus before it was
discovered in the temperate environs of Vancouver Island. It soon
evolved into a new, more virulent, pulmonary disease that quickly
spread to mainland Canada and south into the state of Washington.
That was followed by an outbreak in Oregon of another new strain of
C. gattii, which also displayed increased lethality and
similarly spread throughout the Pacific Northwest.
C. gattii previously was associated with neurological
disease in strains found elsewhere in the world. But the strains
discovered in the Pacific Northwest not only establish a new
environmental niche, but also display increased virulence and
produce severe lung infections.
"We provide evidence that the Pacific Northwest strains originated
from South America, and identified numerous genes potentially
related to habitat adaptation, virulence expression and to clinical
presentation," said Dr. Wieland Meyer, the study's other senior
author.
"Further elucidation and characterization of these genetic
features may lead to improved diagnostics and therapies for
infections caused by this continually evolving fungus," said Dr.
Meyer, who is affiliated with: Sydney Medical School-Westmead
Hospital; the University of Sydney; and the Westmead Millennium
Institute for Medical Research.
This study concludes that: "Public health vigilance is warranted
for emergence in
regions where C. gattii is not thought to be
endemic."
New tests developed for this study by TGen are making it easier to
detect this and other fungi, and could lead to better monitoring
and treatments. The same tools used in this study also were used to
investigate the cause of a fungal meningitis outbreak associated
with steroid back injections, and the recent outbreak of Valley
Fever in the state of Washington.
The journal, mBio, is published by the American Society
for Microbiology.
Collaborators in this study include researchers at the University
of California-Davis, and in the United Kingdom, Australia, New
Caledonia, Thailand, Columbia, and Brazil.
The study, "Cryptococcus gattii in North American
Pacific Northwest: whole population genome analysis provides
insights into species evolution and dispersal," was supported
by a grants from the National Institutes of Health (NIH) and the
Medical Research Council (MRC) of South Africa.
Research reported in this publication was supported by the
National Institute of Allergy and Infectious Diseases of the NIH
under Award Number R21AI098059. The content is solely the
responsibility of the authors and does not necessarily represent
the official views of the NIH.
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About TGen
Translational Genomics Research Institute (TGen) is a Phoenix,
Arizona-based non-profit organization dedicated to conducting
groundbreaking research with life changing results. TGen is focused
on helping patients with cancer, neurological disorders and
diabetes, through cutting edge translational research (the
process of rapidly moving research towards patient benefit). TGen
physicians and scientists work to unravel the genetic components of
both common and rare complex diseases in adults and children.
Working with collaborators in the scientific and medical
communities literally worldwide, TGen makes a substantial
contribution to help our patients through efficiency and
effectiveness of the translational process. For more information,
visit:www.tgen.org.
Press Contact:
Steve Yozwiak
TGen Senior Science Writer
602-343-8704
[email protected]