European Foulbrood 1: What is it and How is it Spread?

European Foulbrood (EFB) is less widespread in Australia than its American counterpart, but it can be a big problem for beekeepers.

European Foulbrood is not present here in Western Australia. But our Eastern States counterparts may be all too familiar with this nasty brood disease. Particularly in Victoria and southern New South Wales, a severe outbreak of EFB can have a even greater impact than American Foulbrood.

European Foulbrood: What is it and why is it a problem?

  • European foulbrood (EFB) was first detected in Australia in the late 1970s
  • The bacterium Melissococcus plutonius causes the disease
  • Larvae of all ages are susceptible to infection, which occurs when they ingest food contaminated with the bacteria
  • The bacteria multiples in the mid-gut of the larvae and competes with it for food  
  • The larvae usually starve to death when they are four to five days old
  • Infected larvae that are very well fed by nurse bees may survive
  • Yet, under-nourishment means these larvae usually grow into undersized adult bees
  • Heavy infestations will affect a large percentage of the brood
  • This can cause the colony to weaken rapidly and honey production to drop
  • Colony death may occur but is rare

How is European Foulbrood Spread?

  • Hives can first become infected when honey bees within the colony rob infected hives
  • Or, other bees that drift in from infected colonies may carry the disease with them
  • As with American Foulbrood (AFB), nurse bees spread EFB within the hive by attempting to remove dead or dying infected larvae 
  • Their mouth parts become contaminated and they then spread the bacteria to other larvae through feeding
  • When infected larvae survive infection, the adults can also spread the bacteria in their faeces
  • Faeces left behind in the cell after a surviving adult bee emerges will infect the next generation of larvae
  • A colony weakened by EFB becomes more susceptible to robbing by other bees, which then spread the bacteria to new areas
  • Swarms and absconding colonies can also spread the disease between areas
  • EFB is highly contagious and bacteria can remain viable for at least two years
  • Beekeepers can accidentally spread EFB by placing infected combs or hive components in non-infected hives
  • Feeding infected honey or pollen or using contaminated tools and equipment can also spread infection

Next week on The Buzz we take a look at identifying (diagnosing) and managing European Foulbrood in your hive.

Adapted from BeeAware – European Foulbrood and the Australian Beekeeping Guide

Image for post Eurpean Foulbrood 1
Nurse bees can spread European Foulbrood to the larvae they feed via their mouth parts.

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