- 1918 Killer Flu 'Came From Birds'
- BBC News
- The Spanish flu virus that killed 50 million people in
1918-19 was probably a strain that originated in birds, research has shown.
US scientists have found the 1918 virus shares genetic mutations with the
bird flu virus now circulating in Asia.
- Writing in Nature, they say their work underlines the
threat the current strain poses to humans worldwide. A second paper in
Science reveals another US team has successfully recreated the 1918 virus
in mice. The virus is contained at the US Centers for Disease Control and
Prevention [CDC] under stringent safety conditions. It is hoped to carry
out experiments to further understand the biological properties that made
the virus so virulent.
- The virus was recreated from data produced by painstaking
research by a team from the US Armed Forces Institute of Pathology. Working
on virus samples from the remains of victims of the 1918 pandemic, the
researchers were able to piece together the entire genetic sequence of
the virus. They found the virus contained elements that were new to humans
of the time, making it highly virulent. Analysis of the final 3 pieces
of the virus' genetic code has revealed mutations that have striking similarities
to those found in flu viruses found only in birds, such as the H5N1 strain
currently found in south east Asia.
- Many experts believe it is only a matter of time before
H5N1, or a similar virus, causes many deaths in humans -- possibly after
combining [reassorting genome segments] with a human flu strain. Crucially,
the mutations identified by the US researchers were found in genes which
control the virus' ability to replicate in host cells. The researchers
say these mutations may have helped the 1918 virus replicate more efficiently.
- At this stage, they say the H5N1 strain shares only some,
and not all, of these mutations. But these mutations may be enough to increase
the virulence of the virus, and give it the potential to cause serious
human infection without first combining [reassorting genome segments] with
a known human flu strain. The researchers believe the 2 other major flu
pandemics of the 20th century -- in 1957 and 1968 -- were caused by human
flu viruses which acquired 2 or 3 key genes from bird flu virus strains.
But they believe the 1918 strain was probably entirely a bird flu virus
that adapted to function in humans.
- Julie Gerberding, director of the US Centers for Disease
Control & Prevention (CDC), said: "By unmasking the 1918 virus
we are revealing some of the secrets that will help us predict and prepare
for the next pandemic." Dr Jeffery Taubenberger, lead researcher of
the Nature study, said: "Determining whether pandemic influenza virus
strains can emerge via different pathways will affect the scope and focus
of surveillance and prevention efforts."
- Professor John Oxford, an expert in virology at Queen
Mary College, London, said the suggestion that the virus had the potential
to jump between humans without first combining [reassorting] with a human
virus made it even more of a threat. "This study gives us an extra
warning that H5N1 needs to be taken even more seriously than it has been
up to now," he said. Dr Terrence Tumpey, of the US CDC, defended the
decision to recreate the 1918 flu virus. He said: "We felt we had
to recreate the virus and run these experiments to understand the biological
properties that made the 1918 virus so exceptionally deadly. "We wanted
to identify the specific genes responsible for its virulence, with the
hope of designing antivirals or other interventions that would work against
virulent pandemic or epidemic influenza viruses."
- ProMED-mail email@example.com
- The Nature paper is published in the 5 Oct 2005 online edition
and is entitled: "Large-scale sequencing of human influenza reveals
the dynamic nature of viral genome evolution. The authors are: Elodie Ghedin1,
Naomi A. Sengamalay1, Martin Shumway1, Jennifer Zaborsky1, Tamara Feldblyum1,
Vik Subbu1, David J. Spiro1, Jeff Sitz1, Hean Koo1, Pavel Bolotov2, Dmitry
Dernovoy2, Tatiana Tatusova2, Yiming Bao2, Kirsten St George3, Jill Taylor3,
David J. Lipman2, Claire M. Fraser1, Jeffery K. Taubenberger4 and Steven
L. Salzberg1,5. (At 1 The Institute for Genomic Research, 9712 Medical
Center Dr., Rockville, Maryland 20850, USA ; 2 National Center for Biotechnology
Information, National Library of Medicine, National Institutes of Health,
Bethesda, Maryland 20894, USA2; 3 Wadsworth Center, New York State Department
of Health, Albany, New York 12201, USA ; 4 Department of Molecular Pathology,
Armed Forces Institute of Pathology, Rockville, Maryland 20850, USA 5 Center
for Bioinformatics and Computational Biology, University of Maryland Institute
for Advanced Computer Studies, College Park, Maryland 20742, USA.)
- The Introduction reads as follows: "Influenza viruses
are remarkably adept at surviving in the human population over a long time-scale.
The human influenza A virus continues to thrive even among populations
with widespread access to vaccines, and continues to be a major cause of
morbidity and mortality. The virus mutates from year to year, making the
existing vaccines ineffective on a regular basis, and requiring that new
strains be chosen for a new vaccine. Less-frequent major changes, known
as antigenic shift, create new strains against which the human population
has little protective immunity, thereby causing worldwide pandemics. The
most recent pandemics include the 1918 'Spanish' flu, one of the most deadly
outbreaks in recorded history, which killed 30-50 million people worldwide,
the 1957 'Asian' flu, and the 1968 'Hong Kong' flu (3).
- Motivated by the need for a better understanding of influenza
evolution, we have developed flexible protocols that make it possible to
apply large-scale sequencing techniques to the highly variable influenza
genome. Here we report the results of sequencing 209 complete genomes of
the human influenza A virus, encompassing a total of 2 821 103 nucleotides.
In addition to increasing markedly the number of publicly available, complete
influenza virus genomes, we have discovered several anomalies in these
first 209 genomes that demonstrate the dynamic nature of influenza transmission
and evolution. This new, large-scale sequencing effort promises to provide
a more comprehensive picture of the evolution of influenza viruses and
of their pattern of transmission through human and animal populations.
All data from this project are being deposited, without delay, in public
archives." - Mod.CP]
- Patricia A. Doyle, PhD Please visit my "Emerging
Diseases" message board at:
- Zhan le Devlesa tai sastimasa Go with God and in Good
- Patricia Doyle, PhD
- The news that the 1918 flu was actually thought to have
originated in birds and shares genetic mutations with the bird flu now
circulating could mean that both might combine.
- As you know, I stated on the program that I thought,
H5N1 might recombine with an H1N1 spanish flu. There has been much research
on the Spanish flu since it has been resurrected and it is not unthinkable
that an escape from a lab or infection of lab personnel could occur.
- There is also another possibility: man manipulation of
H5N1 and H1N1 Spanish Flu.
- Patricia Doyl