European Foulbrood
Krankheiten
European Foulbrood, also called sourbrood (Sauerbrut) in beekeeping German, is caused by the bacterium Melissococcus plutonius.
European Foulbrood, also called sourbrood (Sauerbrut) in beekeeping German, is caused by the bacterium Melissococcus plutonius. Secondary bacteria are frequently involved, which determine the decay of the larvae and the smell. Unlike American Foulbrood, it is mainly the young, still open brood that becomes infected. The larvae take up the pathogen with their food, it multiplies in the midgut and deprives the larva of nutrients, so that it usually dies before capping.
Typical signs are yellowish to brownish discolored larvae lying twisted or shifted in the cell instead of neatly coiled at the cell base. The brood nest looks patchy because the bees remove diseased larvae. If larvae die only after capping, sunken, sometimes cracked cell cappings are found. The dried remains form a dark, glossy scale that, unlike American Foulbrood, can be lifted out easily. The matchstick test is also negative, the mass does not form threads. The colony often smells sour, hence the name sourbrood.
The disease occurs mainly in spring and early summer, when the brood nest grows quickly and the bees' nursing capacity reaches its limits. Nectar dearths, cool weather, too little pollen, old combs, and weak colonies favor an outbreak. The pathogen spreads through robbing, moved combs, contaminated equipment, and through the purchase of colonies and queens.
The shook swarm or artificial swarm method has proven effective: the bees are brushed off the combs, the entire old comb structure is melted down, and the hives are disinfected, for example with hot soda lye or by flaming. Requeening with a young queen known for good hygienic behavior, consistent comb renewal, and a good supply of pollen and food support recovery. There is no approved medication, antibiotics are not an option.
The legal situation varies by country. In Germany, European Foulbrood is not among the notifiable bee diseases; only American Foulbrood, the Small Hive Beetle, and the Tropilaelaps mite are notifiable there. In Austria there is likewise no reporting requirement. In Switzerland, by contrast, sourbrood is considered an animal disease that must be controlled and must be reported to the bee inspector. Anyone moving colonies across borders or giving colonies away should check the rules of the destination country and, when in doubt, consult a certified bee inspector.