Virus: Morator aetatulas
Sacbrood is another relatively common viral infection thought to be passed on to our bees by consuming contaminated food brought into the hive by the foragers.
Although causing very little problem in the hive, bees infected with the sacbrood virus, fail to pupate after being sealed in their cells. Fluid then builds up in-between the body of the larvae and it’s unshed skin forming a fluid sac and giving rise to the name of this disease – SACBROOD.
As the larvae dies and begins to dry out, it turns a dark brown to black colour, giving rise to the characteristic “Chinese slippers” or “gondola-shaped” scales as the head of the larvae curls upward.
As the bees uncap these cells to remove the dead larvae, this gives rise to a “Pepper Pot” brood pattern. As some of the cell cappings become perforated and sunken, the signs of SACBROOD can sometimes be confused with AFB.
TREATMENT: The good news to most beekeepers is that sacbrood is typically a minor inconvenience to a colony. In most cases the hive itself can overcome and eradicate the presence of the disease through no additional steps.
Visual Indications of Sacbrood
In this image, we can see the cell capping torn down to reveal the shrunken curled upward head of the larvae.
Because of their curled up shape, this stage is referred to as CHINESE SLIPPERS.
Pepperpot Brood Pattern
As the bees uncap cells to remove the dead occupants, this gives rise to a "pepperpot" type of brood pattern with empty cells scattered randomly around.
The cell capping will often have pinprick holes in them before they are uncapped.