Early humans 'may have spread TB' 
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 Early humans 'may have spread TB'
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Early humans 'may have spread TB'
By Helen Briggs
BBC News science reporter

The tuberculosis bacterium emerged in East Africa three million years
ago and may have spread around the world when early humans left
their ancestral home, a genetic study suggests.

According to molecular analysis of modern strains, the pathogen is
much older than previously thought, predating other human afflictions
such as the plague.

French researchers hope the work will lead to improved diagnosis and
treatment of TB, which kills three million people each year.

TB is re-emerging in areas such as Eastern Europe, south east Asia,
and sub-Saharan Africa, due to the spread of drug-resistant strains of
the disease and the rise in HIV.

It is caused by the bacterium, Mycobacterium tuberculosis, which attacks
the lungs, giving rise to symptoms such as coughing, loss of appetite,
fever, and night sweats.

'Essential genes'

TB has long been a human disease - tissue samples from Egyptian mummies
over 4,000 years old show signs of infection.

Until now, scientists had believed the disease arose a few tens of thousands
of years ago and then spread rapidly around the world.

But investigation of a rare tuberculosis-causing bacterium isolated from
patients in East Africa suggests the roots of the disease go back much
further.

Molecular analysis suggests that the East African samples and the
commoner strains are all descended from a more ancient bacterial species
that emerged in Africa as long as three million years ago.

"Tuberculosis could thus be much older than the plague, typhoid fever,
or malaria, and might have affected early hominids," said senior researcher
Veronique Vincent of the Institut Pasteur in Paris.

Understanding the ancient origins of the bacterium could help in the
development of new {*filter*} against TB, which is rapidly growing resistant
to the {*filter*} used to treat it.

"Now we have in our hands bacteria that are quite different from the others
and all are able to produce TB," co-worker Cristina Gutierrez told the BBC
News website. "Maybe we could find which the essential genes for virulence are."

The research is published in the first edition of the Public Library of Science
(PLoS) journal, PLoS Pathogens.



Wed, 06 Feb 2008 15:12:30 GMT
 Early humans 'may have spread TB'

Quote:
> http://news.bbc.co.uk/1/hi/sci/tech/4163282.stm
> The tuberculosis bacterium emerged in East Africa three million years
> ago and may have spread around the world when early humans left
> their ancestral home, a genetic study suggests.

We can learn a lot about a species (or a
population) from its diseases (and its parasites).
Humans have a large range of unique diseases
and parasites.  But are they studied as part of
any PA course?

Naah.

One reason for that is the usual PA dopiness.
But another is that the answers such studies
produce are 'inconvenient'.  They don't match
current PA 'thinking'.

Diseases like TB require the presence of a large
host populations, whose numbers must remain
consistently high for hundreds of thousands
of years;  i.e. they never fall to a low level.
Such populations must also occupy their local
habitats at a high density.

Of course, the presence of large numbers and
high density throughout human evolution has
long been obvious from the fact of language,
and from much else.  But PA has never let
obvious facts get in the way of its 'thought'.

Paul.



Wed, 06 Feb 2008 17:17:42 GMT
 
 [ 2 post ] 

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