Reply To: Farms, wild birds and biosecurity re flu esp H5N1

[Martin W]

I’ve posted first part of this to thread on evolutionary biology; but implications for farms n biosecurity, so adding here too:

Further evidence of evolutionary biology at work in poultry farms comes from UK’s H7N3 outbreak. (Not conclusive here, but fits evol biology – as ever with flu.)

Quote:

Birds on the free range unit, however, suffered only a mild form of the flu and none died from the infection….

the virus was transported from the egg farm to the Banhams chicken farm, where it killed some 400 chickens and triggered a drop in egg production by other birds.

note also, from intensive farms:

Quote:

Blood samples from birds on their farm showed that they had been exposed to the H7N3 virus as long ago as four weeks.

– during which, presumably, the virus evolved towards virulence in the “disease factories”

Original, low path virus thought to have been introduced to free-range flock, from wild birds.
Now this may be possible (a few routes mooted).
But, again, leads to serious questions re poultry farming, and conservation.
Do we really want farms that are hermetically sealed from outside world (and yes, that is really impossible, tho can have very tight security)? Ensure wild birds are kept away from poultry farms – like the US farm with not even a tree.

Or do we aim for farming system that can detect bird flus; and have farming systems/measures to guard against introduced strains of flu evolving to virulence?
(Then, can biosecurity really work now, or is it too late; I’ve seen paper on poultry in China market, where had several strains of flu.)

Vets track spread of bird flu strain