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Real Time PCR and reverse
The Influenza virus is an RNA virus so this must be
copied into DNA by a reverse transcriptase step before the pcr amplification
cycles can begin. The Real time machine detects product as it appears
after each cycle; after a small number of cycles when there is a large amount of
virus in the sample and after 30 or more cycles when there is little virus
present so there is a plot in the form of a curve with cycles 1 to 40 on
the horizontal axis and amount of product on the vertical axis (detected by for
instance fluorescence of primer activated by incorporation into product).
Birdside PCR as one might like to call a Roger
Breeze's machine would go through the same steps as above.
The diagnosis at Weybridge, centralisation, when
there is little to diagnose in this country is surely adequate. What
happens when there is a large outbreak I am not sure. They are just trying
to sort out this problem in the USA for human pandemic influenza as all human
diagnosis of H5 is centred in CDC Atlanta.
Putting poultry indoors
I think it is a bit of a myth that this necessarily
provides a solution. Indoors any infection introduced as droppings or from
an infected individual is aerosolised and effectively spread either orally or by
respiraotry route to all or at least many others. This starts infection
like a bushfire, and the birds inside are stressed and probably less healthy and
even immune depressed compared to their healthy happy free ranging
counterparts. These merely share a roost which is regularly cleaned out
and do not live in a dusty atmosphere. So far the two large outbreaks in
European poultry facilities have occurred in birds kept inside. If outside
poultry can be kept away from aquatic birds and crows or sparrows because food
and water is inside perhaps they are less at risk. It will be interesting
to see whether this is so. I can't speak for larger free range flocks
and areas of the country where gulls are prevalent but if food and water is not
put outside at all I wonder if wild birds will mix with the flock.