Foulbrood

from Wikipedia, the free encyclopedia
Typical characteristics of the American foulbrood:
1. collapsed cell cover
2. stringy mucus

The foulbrood are bacterial brood diseases in honey bees . A distinction is made between the European foulbrood (EFB ) caused by Melissococcus plutonius (family Enterococcaceae ) and the American foulbrood (AFB) caused by Paenibacillus larvae (family Paenibacillaceae ). The relatively harmless European foulbrood is also known as benign foulbrood or (due to the sour smell that develops) as "sour brood". American foulbrood, however, is also foulbrood called and is reportable in Germany and Austria notifiable and Switzerland, see chapter organization of animal disease control in animal disease .

American foulbrood (AFB)

The American foulbrood (also called bee plague, Histolysis infectiosa perniciosa larvae apium , Pestis americana larvae apium ) is a disease of the older bee brood, namely the maggot: They are located in the brood cell , which is already closed with a wax lid . In the course of the disease, the entire body structure of the larvae dissolves, leaving only a tough, brown, slimy substance that can later dry up into a dark scab. The American foulbrood does not pose any threat to adult bees, humans or other living beings. The term "American" does not refer to an area of ​​origin, but to the place of discovery; the disease occurs worldwide.

root cause

Nurse bees feed larvae with spores of the Paenibacillus larvae bacteria and thus infect them. The metabolic pathways of the bacterium were clarified at the Technical University of Berlin and at the State Institute for Apiculture in Hohen Neuendorf. After a gene sequence suggested an unusual secondary metabolite, this was identified and the biosynthetic pathway clarified. The antibiotic called paenilamicin does not destroy bee larvae. However, its antibacterial effect helps the bacterium to assert itself against microbial competitors in the larval intestine.

Course of infection

Spores of the bacterium Paenibacillus larvae enter healthy bee colonies with contaminated honey or honeycombs. The spores are distributed in the bee colony through body contact and food exchange. Spores contaminate the honey stored in the honeycomb. Nurse bees contaminate the larval food.

The spores germinate in the intestines of the larvae and multiply as rods ( bacillus ). If the larvae before capping killed the brood cell of bacteria, it is by their cleaning instinct following workers often removed. But if the brood cell is still covered, the larva dies and decomposes into a thread-pulling mass ( matchstick sample ).

Each infected larva that has remained undetected dries up ( foulbrood scab ) and contains up to 2.5 billion new spores after complete decomposition. Collapsing bee colonies are robbed by bees of other colonies, whereby the spores are distributed in their colonies.

Combat

In the event of an AFB outbreak, there is a risk of infecting a wide area through flight and robbery. It is therefore a notifiable animal disease in Germany and some other countries . After the official determination of the disease by the responsible veterinary office, a foulbrood restricted area with at least one kilometer radius around the apiary concerned is set up. Beekeepers can determine whether their bee colonies are contaminated with AFB spores every year by means of food wreath samples. However, the detection of spores in the samples does not mean that the AFB has already broken out. Measures are only to be taken when there is also a clinical finding (slimy cell content, match sample positive). In the past, an AFB renovation usually meant the destruction of all colonies on the stand by sulphurizing (killing the bees) and burning the material. Today, when the tendency to spread is limited and the beekeeper has the appropriate options, they rely on artificial swarming methods and hive disinfection (beehive disinfection). Plastic sticks can also be effectively disinfected. However, any honeycomb material from the infested colonies that has already been incubated must continue to be destroyed or at least delivered to a wax-processing company as so-called epidemic wax. A melting process with defined parameters (temperature, pressure and duration) kills all the spores contained there.

The AFB is also fought worldwide with antibiotics . However, the product has the serious disadvantage that the pathogens are only killed in the active growth phase, but not the endospores as a permanent form. Millions of endospores are present in the dried up "foulbrood scab" in each of the infected brood cells and can survive for more than 50 years. If the accompanying hygiene measures are inadequate, the disease will break out again and again .

The endospores are also spread via the global honey trade. These can then get into the colonies through robbery from unswashed honey jars and honey jars with residual content in the glass container, so that even glass containers with honey jars had to be filled with extinguishing foam until they were emptied .
At the Brigham Young University ( Utah , USA ) is currently exploring the use of phage therapy for the treatment of American foulbrood.

Suspicious facts

Suspicions that make a check (matchstick sample) for AFB appear sensible are:

  • individually remained covered brood cells
  • very patchy brood (weak suspicion, may also have other reasons, e.g. varroosis )
  • Bone glue- like odor when opening the hive
  • Discoloration of the capped brood with sunken or even perforated cell covers

Matchstick sample

positive matchstick test

In the match test, the end of a match with no ignition head is pushed to the bottom of a brood cell that appears suspicious and has been opened shortly beforehand. The sample turns out positive if a slimy thread, similar to a highly viscous adhesive, can be pulled out and no body structure (in the form of a flaccid larval skin) can be recognized. Reliable evidence of the outbreak of the disease can be obtained by examining a sample in the laboratory. A bacteriological or molecular genetic pathogen detection is carried out there. In the case of open brood cells, the matchstick sample does not provide any reliable clues, as the originally slimy content of the infected cells has usually already dried out.

Legal regulations

In Germany, the Bee Disease Ordinance regulates both prophylaxis and protective measures in the event of suspicion or after the official discovery of the disease that is officially combated as a notifiable animal disease .

As a prophylactic measure, every beekeeper can have his colonies examined for American foulbrood by an officially appointed bee expert at any time. The most sensible time for this is in the spring before offshoots are formed . Such an examination is absolutely necessary if the beekeeper intends to sell or dispose of colonies, to supply a mating station or to migrate with colonies of bees . Bee experts issue health certificates for this purpose, copies of which are visibly attached to the hives .

In the case of suspicion or an outbreak of the AFB, no changes may be made to the apiary before the official clarification or determination of the disease by the veterinary office . All persons except the owner and his representatives and assistants, veterinarians and competent bee experts are prohibited from entering.

According to the official determination of the AFB, apiaries, dead bees, equipment, honeycomb material , wax supplies etc. must be disinfected or disposed of harmlessly in the apiary in accordance with the instructions of the official veterinarian. Bee colonies suffering from the disease are either killed ("sulphurized") or treated using an artificial swarm process, depending on the official order .

With the official determination, the veterinary authority also identifies a restricted area with at least one kilometer radius around the apiary concerned, in which all apiaries located there must also be examined for AFB.

European foulbrood (EFB)

The European foulbrood ( Putrificatio polybacterica larvae apium , Pestis europea larvae apium ) is an infection that affects the younger and still open brood (brood cells not yet closed with a wax lid), the so-called round maggots. The primary pathogen is Melissococcus plutonius . Achromobacter eurydice , Enterococcus faecalis , Brevibacillus laterosporus and Paenibacillus alvei have been described as secondary pathogens . The dying maggots turn yellow to brown and lie limp on the cell floor. The dead tissue is still structured and not stringy, but rather watery. It emits a sour, sometimes very penetrating odor. The maggot death usually begins in summer (July).

EFB has been growing rapidly in Switzerland since 1999 and is particularly widespread in 2009/10, especially in areas with a high density of bees.

Like AFB, EFB is a disease that is very difficult to eliminate and is still often underestimated. Refurbishment attempts usually fail. The two-time wiping process according to Wolfgang Ritter has brought initial success. The bees can easily reintroduce the bacterium from infected neighboring colonies. The pathogen dies at 78 ° C when cleaning the material with 5% hot sodium hydroxide solution, 6% hot soda solution and 70% alcohol, respectively. Cleaning fuel. Since the bacterium is also present in the wax and propolis, this must first be scraped off or flamed.

Note: The terms maggot versus larva

In beekeeping, the term “ Made ” is used in relation to the brood of bees (for example in “Round Made” or “Streck Made ”). In the biological and scientific context, "Made" but refers to a developmental stage Diptera (Diptera). For honey bees, which belong to the hymenoptera (Hymenoptera), the expression “ larva ” would be appropriate.

literature

  • Eva Forsgren: European foulbrood in honey bees. In: Journal of Invertebrate Pathology. 103, 2010, pp. S5-S9.
  • Edmund Herold: New beekeeping school. 6., thorough. revised Edition. Revised by K. Weiss. Ehrenwirth, Munich 1984, ISBN 3-431-01850-5 .
  • Friedrich Pohl : The foulbrood: prevent, recognize, fight. Ehrenwirth, Munich 1999, ISBN 3-431-05001-8 .
  • Frithjof Koithan: The current risk potential of the American foulbrood, causes and possible control strategies. Dissertation . Department of Veterinary Medicine at the Justus Liebig University, Giessen 2002. (PDF; 771 KB)
  • Federal Ministry of Food, Agriculture and Consumer Protection (Ed.): Guideline for combating American foulbrood bees in Germany. Status: January 2013.

Individual evidence

  1. ↑ Bee Disease Ordinance in Germany
  2. ↑ The Federal Authorities of the Swiss Confederation, Legislation, State Law SR 916.401 Animal Disease Ordinance .
  3. ↑ Friedrich Loeffler Institute (FLI), Federal Research Institute for Animal Health: Information: American foulbrood , (online PDF) ( Memento from July 23, 2019 in the Internet Archive )
  4. ↑ Bavarian State Institute for Viticulture and Horticulture: Information: American Faulbrut , (online PDF) ( Memento from October 21, 2016 in the Internet Archive )
  5. ↑ Friedrich Pohl, Werner von der Ohe: American foulbrood - how dangerous is it? In: German bee journal . Issue 8/2007, pp. 14, 15.
  6. ↑ Roderich Süssmuth u. a .: Paenilamicin - structure and biosynthesis of a hybrid polyketide / nonribosomal peptide antibiotic of the bee pathogenic bacterium Paenibacillus larvae. In: Angewandte Chemie . Volume 126, No. 40, September 26, 2014, pp. 10998-11002. doi: 10.1002 / anie.201404572
  7. ↑ Do not feed bees with honey , on Wissenschaft.de from April 6, 2020
  8. ↑ foulbrood source glass container? In: General German beekeeping newspaper . Issue 11, 2011, p. 13.
  9. ↑ Bee Killers: Using Phages Against Deadly Honeybee Diseases. on YouTube, accessed June 5, 2016.
  10. ↑ Using microscopic bugs to save the bees. from the Brigham Young University website, accessed June 5, 2016.
  11. ↑ Imdorf A. et al. (2005) Sauerbrut - an insidious brood disease. Agroscope Liebefeld- Posieux, Swiss Center for Bee Research. Available online. URL: https://www.agroscope.admin.ch/agroscope/de/home/themen/nutztiere/bienen/bie- nenkrankheiten / sauerbrut.html [as of February 17, 2017]
  12. ↑ Imdorf A., Roetschi A. & Kuhn R. (2007) Rapid expansion of the sour brood. Schweizerische Bienen-Zeitung 09/2007: 6-9. Available online. URL: https: //www.agroscope.admin.ch/agroscope/de/home/themen/nutztiere/bienen/bienenkrankhei- ten / sauerbrut.html [as of February 17, 2017]
  13. ↑ Charrière JD et al. (2012) Guide to bee health from the Center for Bee Research. ALP forum 84: 1-35. Available online. URL: https: //www.agroscope.ad- min.ch/agroscope/de/home/themen/nutztiere/bienen/bienenkrankheiten.html [as of February 23, 2017]
  14. ↑ Swiss Confederation (2016) Report on the implementation of the national action plan for the health of bees. Federal Council report. Bern, 1-37. Available online. URL: https://www.newsd.admin.ch/newsd/message/attach- ments / 46 469.pdf [as of February 23, 2017]
  15. ↑ Raphael S. von Büren et al .: High-resolution maps of Swiss apiaries and their applicability to study spatial distribution of bacterial honey bee brood diseases . In: PeerJ . January 31, 2019, ISSN  2167-8359 , p. e6393 , doi : 10.7717 / peerj.6393 ( peerj.com [accessed January 31, 2019]).

Web links

Commons : Paenibacillus larvae  - Collection of images, videos and audio files