European Foul Brood

 

Causal agent

Melissococcus plutonius a bacteria

Similar appearance to streptococci and can occur in chains, but can be pleomorphic. Gram +

Requires anaerobic culture and colonies may take 4 days to appear.

Other names

EFB

Age group

Very young larvae

Egg

Larvae

Pupae

Adult - worker

Drone

Queen

No

Yes

 

 

 

 

Clinical signs

Season

Generally seen in the springtime

The larvae are not glistening white. They change colour to a tan (shown) and eventually black. As the larvae die early before they are capped the house bees remove the larvae

Outside

None

Odour

Odour sour smell

Brood

Spotty pattern on the broom frame. May appear as a crossword puzzle.

Cappings

Open cells unsealed brood. A few torn cappings

Larvae appearance

Larvae are white to yellow to black. May be granular in appearance. Intestines may be visible through skin

Scales (larvae)

Larvae die very young and appear as a rubbery pile at bottom on cell. Loose within the cell. Lies usually twisted in cell.

Other

May be no clinical signs

Infectivity

 

Larvae infected through honey

 

The spores are resistant for 3 years

Transmission

 

Through honey

 

Transmission between hives by drifting and robbing

Post-mortem Lesions

 

Very young larvae died at bottom of cell, before capping

Diagnosis

 

Appearance of brood

Culture

 

Field diagnosis using lateral flow devices looking for antibodies in the bees

Treatment

 

Tetracycline and Tylosin. Provide in spring and autumn in sugar

 

Clinical signs predominate when colony is under stress

Control

Maintain a strong colony lots of food and re-Queen annually.

Ensure that the crude protein content of bees is above 40%. When bees drop to less than 30% they become more susceptible to EFB.

Control using the shook swam technique

Severe cases destroy hive by burning

Common differentials

 

American Foul Brood

Zoonosis

None