Avian influenza - situation in Bangladesh

by greg1usa | June 1, 2008 at 02:55 pm

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Avian influenza - situation in Bangladesh

28 May 2008 -- The Ministry of Health, Bangladesh has confirmed its
first case of human infection with H5N1 avian influenza. The case was
identified retrospectively as part of seasonal surveillance activities
run by the International Centre for Diarrhoeal Disease Research,
Bangladesh (ICDDRB).

Avian influenza is an infectious disease of birds caused by type A
strains of the influenza virus. The disease occurs worldwide. While all
birds are thought to be susceptible to infection with avian influenza
viruses, many wild bird species carry these viruses with no apparent
signs of harm.

WHO is coordinating the global response to human cases of H5N1 avian
influenza and monitoring the corresponding threat of an influenza
pandemic.

Study shows hybrids of bird flu and human flu viruses fit well, could occur [q
url="http://www.canadaeast.com/wellness/article/312551"]

TORONTO - An experiment mating H5N1 avian flu viruses and a strain of human flu in a laboratory produced a surprising number of hybrid viruses that were biologically fit, a new study reveals.

And while none of the offspring viruses was as virulent as the original H5N1, about one in five were lethal to mice at low doses, showing they retained at least a portion of the power of their dangerous parent.

The work suggests that under the right circumstances - and no one is clear what all of those are - the two types of flu viruses could swap genes in a way that might allow the H5N1 virus to acquire the capacity to trigger a pandemic. That process is called reassortment.
[/q]

This
work, done at the CDC, was conducted to study the reassortment
potential of H5N1 and H3N2 viruses. H3N2 is one of two human influenza
A viruses that cause disease during flu season.

The study was published in PLoS Pathogens, one of the Public Library of Science journals.

Reassortment
studies can be done one of two ways. One involves simultaneously
infecting cells with the two viruses and seeing what nature produces.
The other involves making viruses by piecing together combinations of
synthesized human and avian genes.

"It's like Lego," Donis, head
of the molecular virology and vaccines branch, says of this approach,
which was the one used for this study.

But this is a game of Lego
where it's not clear from looking at the pieces which will go together
into a structure that will hold. "We really don't understand the rules
of engagement for playing the Legos. We don't know what makes these
things connect well or not connect well," he admits.