WW1 Flu Deaths by Tens of Millions caused by Cadavers of US Pigs

US Pig Flesh caused Spanish flu death of tens of millions in 1918 an Message List
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1918 "Spanish" influenza pandemic down to pig flu RNA
http://www.newscientist.com
(It is called Spanish flu because unlike the US and UK, Spain was not
in the war and had no wartime censorship, therefore reported
the plague of deaths.)

12:55 07 September 2001 by Douglas Fox

The joining of genetic sequences from pig and human influenza created the deadly
strain that killed up to 40 million people around the world in 1918 and 1919,
say Australian researchers.

Unlike other flu outbreaks, which prey heavily on the old and the young, the
1918 "Spanish" flu killed many healthy people in their prime. "It tended to give
people pneumonia," says virologist Mark Gibbs, who led the research at the
Australian National University in Canberra. "That suggests that it infected much
deeper in the lungs than influenza normally does - that it had a different
tissue specificity."

Flu pandemics are thought to arise when a human flu virus acquires a bird flu
gene, which helps it evade human immunity. Smaller pandemics in 1957 and 1968
were triggered this way. But the ANU team found no trace of genetic material
from avian flu in a key gene that helped the 1918 virus infect cells. Instead,
they identified a fragment of a gene from a pig flu strain.

The new analysis boosts researchers' knowledge of the way human influenza can
mutate - which will be vital for understanding how another pandemic might arise
in the future, says the team.
Lung biopsies

Jeffery Taubenberger of the Armed Forces Institute of Pathology in Rockville,
Maryland isolated gene sequences for the 1918 virus in 1987. These samples were
found in lung biopsies from two American soldiers who succumbed in 1918, and in
the lungs of a third victim who was exhumed after 80 years from a grave in the
permafrost soil of Alaska.

When Taubenberger analyzed the 1918 gene sequences - specifically a gene called
hemagglutinin, which helps the virus infect cells - he found no evidence that it
came from birds, and no clues regarding the source of the virus's
aggressiveness.

Gibbs took a different approach. Rather than analyzing hemagglutinin as a whole,
he used special software to see if different parts of the gene came from
different sources. He found the middle half of the gene seemed to come from a
pig virus.

This pig segment might alter the virus's tissue specificity - pushing it deeper
into the lungs - and also help the virus escape human immunity. Gibbs believes
the virus acquired that gene segment just months before the pandemic started,
and "it seems very likely that this triggered the pandemic."

However, some researchers are doubtful. Taubenberger says the middle part of the
hemagglutinin gene appears pig-like because this gene has evolved more slowly in
pig viruses.

Gibbs counters that less than ten per cent of the 1918 hemagglutinin gene would
evolve slowly (and therefore appear pig-like) for this reason, whereas his
results show that fully half the gene comes from pigs.

Journal reference: Science (vol 293, p 1842)
http://www.newscientist.com/article/dn1263-1918-spanish-influenza-pandemic-down-to-pig-flu-rna.html

(Other sources indicate that Ft Riley Kansas reported some of the first instances of the flu.)