Bailey wrote( many years ago):
> was wrongly attributed to the mite, which causes
no overt symptoms. The disease was almost certainly caused by bee paralysis
virus, which does cause the symptoms and is independent of the mite, and
which is similarly associated with large densities of bee colonies.

I am not so sure about the above.

1. plenty of overt symptoms of TM infestation

2. Bee paralysis virus rarely caused problems before mites. I mean almost 
NEVER in the U.S. Most commercial beeks considered the research of Bailey 
(U.K.)  as only of minor interest in the U.S. until mites arrived. Before 
mites in Florida yards of 600 hives ( larger densities than Bailey would 
ever see in the U.K.) between honey flows were not uncommon in the largest 
operation and active BPV was never seen.
Although would be found in tests.

In Australia today holding yards of over a 1000 hives by Browns bees are not 
uncommon between flows with no BPV issues and you can find BPV in most hives 
if you test.

As the CCD working group found most common bee virus are found in most 
hives. Strong bees with healthy immune systems are for the most part immune 
to virus issues. One reason the search for a virus alone as the cause for 
CCD is not a big priority for most beeks because there is no solution for 
virus issues except healthy bees.

I agree the hives in England might have had weakened immune systems back 
then which lead to the widespread hive lost more than the tracheal mites BUT 
if placing a bet I would still bet the tracheal mites caused the virus 
issues to rise to cause problems. . back in the 80's I had a bee tested ( 
among 50 sent) which had around 200 tracheal mites in the bees black colored 
trachea.

Bee paralysis virus is easy to detect as the bees can not fly or many times 
even climb the comb. However mostly in the advance stages.

I am not an expert on what has been named Isle of Wright disease but am very 
familiar with tracheal mites ,symptoms and virus related to tracheal mite 
infestations.

bob 

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