Classification of AFB
Classification of AFB
A colony is said to have AFB when one or more of its larvae are fed enough spores to kill them.
In some colonies, the beekeeper may never be aware that a diseased larva or pupa has been produced. The house bees may remove diseased larvae as fast as they become infected, so all the beekeeper sees is a spotty brood pattern (Fig. 13).
The house bees may do this effectively enough to eliminate the infection from a colony.
Infections where no visual symptoms appear in the colony are called “inapparent” or “subclinical” infections. However, it is not possible to differentiate between a colony that is contaminated with spores and has no diseased larvae or pupae, and one that has a subclinical infection.
We may never know how many colonies develop subclinical infections of AFB and eliminate the disease by themselves.
Many beekeepers have noticed colonies that appear to recover from AFB. Having found a colony with a single diseased larva or pupa, they check the colony a few days later before burning it and are then unable to detect any sign of the disease.
It pays to be vigilant
The danger for beekeepers is that although some colonies may eliminate the disease completely, for other colonies the recovery will only be temporary. Because there may still be large numbers of AFB spores in such colonies, they may develop visual symptoms of the disease at a later date, and the symptoms will be severe enough to destroy the colony.
Obviously, colonies with subclinical infections are a factor in the spread of AFB. Even if beekeepers carefully check every frame of brood for diseased larvae and pupae before removing frames to place in other colonies, they cannot guarantee that they are not going to spread the disease.
How well do you know what you need to know about AFB and beekeeping? Take our short quiz and find out.
Our videos cover everything from your legal obligations to how to recognise AFB, collecting cell and bee samples and more.
There’s a lot of good information here, telling you everything you need to know about recognising AFB: the visual symptoms, smell of AFB and more.
New Zealand beekeepers have a number of legal obligations that must be met regarding AFB disease. Read the shortened list in summary, here.
Most hives become infected because bees, honey or equipment have been put into a hive from another hive that is infected with AFB. Lower your chances of an AFB infection by reading this section.
Find out when the next AFB Recognition and Competency Courses, or Refresher Courses are available. These are held throughout the year in various New Zealand locations across the South Island and North Island.