>"The problems I see in my yards now is nosema ceranae and to be honest some
>virus issues in my opinion I which should not be seeing as I have had
>excellent varroa control this spring. Although only an occasional cell or
>two I see larva problems and only in late stage larva. Four beeks looked at
>what I am seeing and all had different opinions. Two thought possibly stone
>brood and two not sure but all thought was not European foul brood."
>
>Bob
Sounds like sacbrood. Sacbrood is much more widespread than most
beekeepers realize. It has been found at levels of 80 to 90% in honey
bee workers, 80% in pupae and nearly 50% in varroa mites. They pick it
up by cleaning out dead larvae, and feed it to the each other and the
healthy larvae. Many reports state that it is inapparent or even that
it has no effect on the adults. Bailey stated more than 50 years ago
that honey bees infected by sacbrood show very high levels of the
virus in the brain and that this could lead to premature foraging and
colony collapse.
In my opinion Bailey, Ball and the rest have accurately described much
of what we are now seeing. In England they are saying that hives are
failing with 10% the number of mites than was formerly required to
kill them. Obviously, it is not the mites that are killing them; they
serve only as an indicator of the health of the colony. High mites
levels mean virus levels are probably already out of hand. An
infestation of sacbrood can be easily overlooked if the bees are
quickly removing the dead larvae (by eating it) but if it is
accumulating in the bees' brains, it could have far-reaching effects
such as confusion, disorientation, premature foraging, failure to
return to the hive, etc.
Brenda Ball stated in 2004:
> There is increasing evidence that the global spread of Varroa destructor has resulted in a significant change in the type and prevalence of viruses causing mortality in honey bee colonies. This is primarily because the mite has provided new routes of transmission for naturally occurring, endemic virus infections.
> In mite infested colonies a much more successful strategy for honey bee viruses would be to multiply within the host without causing a rapidly fatal infection. The longer a severely infected individual survives in the population, the more opportunity the mite has to feed on that individual and transfer the virus to a new host. This now explains the almost ubiquitous occurrence of deformed wing virus.
> After the turbulent years of dramatic colony losses that accompanied the arrival of varroa, have we now reached a relatively stable situation again where both mite and predominant virus can be managed, or could the decline in certain types of virus leave a niche open for opportunistic invaders? Only time will tell, but we should certainly be alert and prepared for more trouble with viruses.
Also, in 2004, SUMPTER and MARTIN wrote:
> large mite populations have been responsible for vectoring bee viruses between honey bees. The viruses, which previously spread relatively slowly and caused colony mortality extremely rarely, are now thought to be responsible for the world-wide death of millions of
mite-infested honey bee colonies.
> While the link between mites, viruses and colony collapse has been established, there is not as yet a full understanding of why and when a Varroa -infested honey bee colony will collapse. In particular, the important question in determining the mite load that will cause a virus epidemic and colony collapse has remained largely unanswered.
Yan Ping Chen in 2007:
> SBV is the most widely distributed of all honey bee viruses. Since its first identification in the United States in 1913, infection of SBV has been found on every continent where A. mellifera honey bees are present SBV infection has been associated with varroa mite infestation. SBV
was detected in large amount of adult bees from varroa mite–infested colonies
SEE:
Honey Bee Viruses by Yan Ping (Judy) Chen and Reinhold Siede
The dynamics of virus epidemics in Varroa -infested honey bee colonies
by D. J. T. SUMPTER and S. J. MARTIN
Prevalence and Seasonal Variations of Six Bee Viruses in Apis
mellifera L. and Varroa destructor Mite Populations in France Diana
Tentcheva, et al
Virus infection causes specific learning deficits in honeybee foragers
by Javaid Iqbal and Uli Mueller*
Intricate transmission routes and interactions between picorna-like
viruses (Kashmir bee virus and sacbrood virus) with the honeybee host
and the parasitic varroa mite by Miaoqing Shen, Liwang Cui, Nancy
Ostiguy and Diana Cox-Foster Diana Cox-Foster
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