Sacbrood virus, SBV

  • Mortality 60% 60%
  • Infectivity 60% 60%
  • Healing difficult 80% 80%

Sacbrood is a viral infection of brood (virus SBV).

It was one of the first insect viruses to be identified (1917).
It looks much alike with Acute Paralysis Virus.

On larvae, the virus is detected in the fat, muscle tissue and trachea.
In adult’s bees, is detected in large quantities in their tissues.
The virus lies mainly in the head, especially in sub-pharynges glands from where the virus passes to larvae.
Initially during an infection, the virus particles are multiplied in the developing larva, which appear to develop normally until after being capped over
The infected larvae turn a pale yellow colour; they remain stretched out on their backs, heads towards the top of the capped cell.
Liquid accumulates between the body of the larva and its unshed skin, thereafter the larvae become as a fluid-filled sac, hence the name
The larvae will eventually die and begin to dry out, turning from a dark brown to black colour, giving rise to the characteristic of ‘Chinese slippers’ or ‘gondola-shaped’ scales.
As the larvae die, the worker bees will uncap the cells in order to expose them
There are no treatments available for sacbrood, but the virus will not usually be a large problem, tending to affect small areas of brood only.
However, in cases where there are large areas of brood clearly affected then it would be best to re-queen the colony.

The bees infected by the virus, do not present any external change. However they can not carry pollen, thus are converted into collector bees but unable to collect and carry pollen.
More often the bees die prematurely, without showing any symptoms.

Infectious are the white, rotten larvae only. During the cleaning process of the cells, the bees are infested by the virus and through the sub-pharynges glands they transfer the virus into the brood’s food.
The disease spreads rapidly in the spring, when the rate of infected catering-bees is greater.
The virus seems to survive the winter in the adult’s bees. The brown colour dried larvae are not infectious.

The worker bees will be in a reasonable position to successfully remove the dead brood from the cells.
Exchange of infected wax helps the spread of infection. In cases where there is a large infection of the brood it would be better to replace the queens in the colony.

The main cause for the development of this virus is the inadequate supply of food to the brood. The sacbrood appears as a side effect of varroasis when the number of mites is very large, so it must be taken care for the reduction of infectious load of varroa mites.


By our devised solutionin which we re mixing Aloe vera Gel No 15, Vitamins B12 and Bee pollen tablets no 26, and by sparying the solution onto the bees, we have succesfully overcomed this condition and our Greek beekeepers are now ejoying very strong healthy collonies.

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