Team:NAWI Graz

Beesensor



Bees are a vital factor of our ecosystems and our economy



The health of our bees is very important


But they are facing a dangerous threat!

The American foulbrood, the single most deadly bacterial disease for bees.

Early detection is a key to good policy of treatment and prevention of American foulbrood. Our vision is to give beekeepers a weapon in the fight against this deadly disease so they themselves can keep their hives healthy and safe.

American foulbrood


The American foulbrood (AFB) is a bacterial disease, which can cause the total collapse of a colony and can spread rapidly. It is caused by Paenibacillus larvae, which digests infected bee larvae. The bacterium persists as an endospore and remains infectious for decades[1]. To kill larvae, a certain number of spores is necessary and for a clinical outbreak of the disease the hive needs to contain a certain number of spores, which depends on the strength of the colony[2]. The digested larvae turns into mucus from which infection spreads within the hive. Adult bees are immune against the bacteria. Bacteria are spread from hive to hive by already "infected" bees who don’t find their colony and enter other hives. With the time the infected colonies become weaker and will die if they are not being treated by the beeekeeper.

Consequences


The consequences of the disease are dire. Unless the disease is detected early or the colony is very strong, the hives and the bees need to be burnt in order to avoid the spread of the disease. The disease is so dangerous that state regulations prescribe all the necessary steps[3] and let the beekeeper no freedom of decision, once the disease is detected. (Read more at our Human practice page)



Foulbrood sanciton

"Beehives with american foul brood should be burned due to spores that remain viable for up to 40 years”. Credit1

Current diagnostic methods


There is a variety of governmentally approved methods for the diagnosis of American foulbrood and the detection of P. larvae.1

  1. The clinical manifestation of the disease can be identified visually. In this stage the complete destruction of the hives might already be necessary
  2. Culture methods are reliable and common. Further analysis by PCR is possible but rarely done. The advantages are the reliability and the early stage when detection is possible.
  3. Quick tests are available but unreliable nor sensitive. They are not governmentally approved

Quick tests are rarely used by beekeepers and have no value for beekeeping laboratories.
On one hand, the culture methods are used far more commonly and are the core of monitoring programmes, which seek to gain data and prevent before it manifests clinically, as they are sensitive and reliable. On the other hand, these methods are time consuming, labor intensive, costly, need institutional infrastructure and the data about the sample are in the hands of others, which is something many beekeepers want to avoid.

Vision


We want to develop a fast, cheap, reliable and easy method for the early detection of american foulbrood2.



Beehives need to be checked regularly in order to recognize any threat arising. Many beekeepers don’t participate in monitoring programmes due to a variety of reasons. Therefore the number of infected hives is unnecessary high and we want to address that problem by giving the beekeepers a tool for pathogen detection, so they do not need to rely on institutions. If the beekeepers agree, the data can be used to provide a map with zones of high occurrence.

Description


We are going to bind bacteriophages which are specific to P. larvae to the surface of an electrode via linking molecules. Both vegetative P. larvae bacteria and their spores bind to phages[4]. Once the spores are bound to the phages and are immobilized near the surface of the electrode, a drop of electroconductive solution allows to perform an EIS-measurement (electrical impedance spectroscopy) with our device[5].

This is how a in-field-measurement with our device looks like (the adding of the electroconductive solution is not shown):

Inspiration


The inspiration to do this project has come because one of our members is a beekeeper and has felt the disease as a threat to him and his family, who live as professional beekeepers. We were looking for a method to improve the existing approach of early detection and have come up with the phage-based EIS-measurement – the foundation for Beeosensor[5].


References

[1] Foul brood disease of honey bees:recognition and control. Archived March 18, 2009, at the Wayback Machine Central Science Laboratory National Bee Unit, Department for Environment, Food and Rural Affairs (DEFRA); United Kingdom
[2] Gende et al. (2011). Searching for an American foulbrood early detection threshold by the determination of Paenibacillus larvae spore load in worker honey bees. Bulletin of Insectology. 64. 229-233.
[3] § 4 BiSG, Bienenseuchengesetz – the Austrian law for bee diseases
[4] Brady, Thomas Scott, "Bacteriophages for Treating American Foulbrood and the Neutralization of Paenibacillus larvae Spores" (2018). All Theses and Dissertations. 6929.
[5] Tlili et al. (2013). Bacteria Screening, Viability, And Confirmation Assays Using Bacteriophage-Impedimetric/Loop-Mediated Isothermal Amplification Dual-Response Biosensors. Analytical Chemistry. 85. 4893-4901

Credits

By Jrmgkia (in Wikimedia). Licence: Creative Commons