wild birds as asymptomatic carriers - implications

[AlaskaDenise]

Kevin Winker, UAF ornithologist, etc., has studied the migratory bird & disease connection for years. He said that among the many things they "don't fully understand" is what happens to birds' immune systems during migration.

They wrote that their immune systems may partially shut down during migration and this could account for why we don't see more diseases from one continent being spread to another. Realistically, for all the intercontinental species mingling here - there should be far more disease. So WHY isn't there more? Is it due to this immune system shut down? Do many asymptomatic carriers die during migration?

How long is a bird an asymptomatic carrier? When would the virus clear from a host that was an asymptomatic carrier? Do these birds develop antibodies, or do they need to be actively infected to develop antibodies? (I would think so, but???)

The other factor in migratory bird transmission was covered by a recent news article - that these birds are somewhat stationary during their nesting period & the genetic mixing may not occur until just prior to their migration south. Then that same immune system shutdown factor kicks in again.

Anyone have any further information on this subject?
(have I used up my allowance of questions for one post?)

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[AlaskaDenise]

Re: wild birds as asymptomatic carriers - implications

During a little research, I discovered this interesting fact:

Death during migration takes a heavy toll. It is estimated that half of all migrants heading south for the winter will not return to breed in the spring.

Perhaps our migrants with immune systems that shut down during migration are part of the group that doesn't return.

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[GaudiaRay]

Re: wild birds as asymptomatic carriers - implications

If so, in a few cycles, won't the bird population be decimated?

 

[AlaskaDenise]

Re: wild birds as asymptomatic carriers - implications

Not as long as they average at least 2 offspring.


The information was provided by avid birders describing the many perils created by humans, so they may not have prioritized that detail.

Thankfully nature works better than the markets (longrun).

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[LMonty]

Re: wild birds as asymptomatic carriers - implications

Thankfully nature works better than the markets (longrun).

as long as you dont lose the goose that laid the gold(en) egg!

sorry, couldnt help myself...