Peter Edwards said;
> No - but not sure that I have looked that carefully.  For EFB I would
> usually look at the gut.  If yellow OK, if white suspect EFB and look at
> under the microscope for bacteria.

EFB is on the rise in the U.S. in commercial operations and for one simple
reason.

Easily mistaken for PMS & no preventive meds given in many operations.

 I always hesitate these days to describe the real world of commercial
beekeeping as it has little in common with hobby beekeeping and the mindset
of the "live and let die mindset". I do not mean to slam the mindset , quite
the contrary, but in order to keep healthy bees when in holding yards of
thousands then disease has to be held in check.

Healthy bees are an absolute these days to survive.

Moving on:
EFB has long been a minor issue in the U.S. mainly because of the decades of
use of terramycin which controls the disease. Things are now changing.

When terramycin resistant AFB
was found then many commercial beeks dropped terramycin use and either
stopped using terra altogether as a AFB/EFB preventative or started using
tylosin when AFB was seen (per label) or as a preventative ( against label).

Stopping terramycin use gives rise to EFB getting a foothold in a large
operation. True if caught in time EFB problems can be turned around but very
little burning or sterilizing takes place in the U.S.

 Because tylosin as no
effect on EFB then EFB once it gets a foothold can spread through an outfit.

Now what has changed is that the larger operations are having problems
controlling varroa. Why?  Hives are being forced to raise brood for longer
times of the year in order to make grade in almonds and also produce brood
for splits.

Raising brood means raising varroa.

 Some outfits are losing 50% of their hives yearly ( Mendes 2008 ABF 
convention speech) due to various
reasons. Constant splitting after various pollinations has become a common
practice( also from the Mendes speech).

Keeping bees in hives by splitting whenever hives are strong enough to split 
has saved many operations. Most large operators spilt more than once a year 
now.

Also a form of varroa control.( as pointed out by Peter B. in his post)

When varroa issues rise then parasitic mite syndrome (PMS) raises its ugly
head. PMS can be spotted at a glance by most commercial beeks. Common in
hives these days. Talked about on BEE-L by both Randy Oliver and 
myself.(BEE-L archives)

 In
fact we have both noticed that what is different today is that *virus* 
issues
are *now* being found in hives which are *not* over varroa threshold.

A fact Dr. Shiminuki   (Ret. head of Beltsville and named  PMS) never told 
us 20
years ago might happen.

My *personal opinion* is the reason we now see PMS in hives with varroa 
loads
below threshold is because of a bees weakened immune system. Once the beek
gets control of nosema C. and other problems I see less PMS in hives with
varroa loads below threshold.

I see less EFB in strong healthy hives also but not sure exactly why this 
is.

If still reading my point is that PMS and EFB look very similar and without
testing ( as pointed out by others in the discussion) it can be hard to tell
EFB from PMS which can lead to deadout boxes being repopulated later in the
season (or right away) giving rise to new EFB problems in new splits.

bob

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