Diseases

Varroa mite

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Control Tools

  • Diagnostics availability

  • Commercial diagnostic kits available worldwide

    Pathogen detection

    Standardized methods are available (OIE).

    Different medicaments can be used for diagnosis of V. destructor, which can lead to residues in honey and/or wax according to the characteristics of the active ingredients.

    Disease diagnosis

    Different recommendations for detection in different countries:

    • - Counts of natural mite fall on sticky bottom boards (mainly in Mid/ Northern Europe)
    • - Analysis of adult bee samples (“ether roll” in USA);
    • - Description of a “powdered sugar roll” in USA (Reuter & Spiwak) and Europe. Advantage: can be performed on live bees and in the field, bees are returned to the hive.

    Determining threshold levels within the “Monitoring project” and “Tolerance breeding project” in Germany, and SMARTBEES project,

    National Bee Unit in UK has a Varroa Calculator, advising when to treat based on a number of parameters.

    PCR-based methods are available to detect and quantify viruses but hardly usable for the routine diagnosis.

    Treatments that can be used during the honey flow are required in some countries.

    GAPS:

    Pathogen detection

    Detection level and relation to mite population and colony size.

    Disease diagnosis

    The need of diagnosis is required for treatment purpose not for quarantine or surveillance restrictions.

    Damage thresholds are dependent on:

    • - bee density (population)the geographical regions & climate
    • - the time of the year
    • - bee races & Varroa haplotype
    • - beekeeping management practices
    • - virus load (type and quantity)

     

    Development and description of a standardized method (Dietemann et al., 2013):

    • - bottom board (used by beekeeper for treatment decision)
    • - bee samples
    • - bee brood
    • - virus load (virus diversity and quantification of viruses)
    • - synergies between the different factors

    There is a need to verify the treatment efficacy. The efficacy is evaluated before a veterinary medicinal product is authorized.

    However, resistance may have developed to some of the active substances over time and this should be ascertained prior to treatment, e.g. through bioassays to identify phenotypic resistance or DNA-based assays to identify mutations known to be associated with resistance.

    There is still a need to revise and improve Integrated Pest Management programmes and ensure that they are specific to the local conditions (climate, honey flow, Varroa dynamics).

  • Commercial diagnostic kits available in Europe

    See section above "Commercial diagnostic kits available worldwide".

  • Diagnostic kits validated by International, European or National Standards

    No kits but methods exist (OIE).

  • Diagnostic method(s) described by International, European or National standards

    OIE Manual of diagnostic tests and vaccines for Terrestrial Animals.

    If the disease is a notifiable disease, the National Reference Laboratory has to approve the diagnostic methods and adopt treatments. Notifiable status is varying among the countries.

    GAPS:

    Varroosis is not a notifiable disease at the EU level. However, national regulations are not harmonized.

    In the regulatory framework, EU harmonization is needed.

    Depending on the epidemiological situation of each member state, the veterinary services and competent authorities should be involved in the development of control strategies. However, in some member states this is left down to the stakeholders, i.e. the beekeepers. Advice is provided by the veterinary services, but they have not the time to do this specifically for apiculture.

    Treatment success is dependent on a good treatment strategy which has to be adapted to the conditions of the different country.

  • Commercial potential for diagnostic kits in Europe

    There would be a market if the price is low and the test is not time consuming.

    GAPS:

    A diagnostic tool for early and easy detection of the disease is needed.

    A tool to assess the colony status is needed: i.e. immunity, virus and Varroa loads and stress.

    A tool to test the efficacy of treatment and possible Varroa pharmaco-resistance is also needed. The latter should be ascertained prior to treatment, e.g. via bioassays to identify phenotypic resistance or DNA-based assays to identify mutations known to be associated with resistance.

    However, good beekeeper colony management and husbandry skills are better and needed more than a new test.

  • DIVA tests required and/or available

    Not applicable. So far, no vaccination is available.

    GAPS:

    It has not been proved that an eradication of Varroa mites for certain regions is possible.

    There are two territories in Europe that are classified Varroa-free: Åland Islands, FIN (2013) and Isle of Man, UK (2015). However, the Animal health law could remove this protection.

      

  • Opportunities for new developments

    Low for industry. High for research institutes.

    GAPS:

    Pharmaceutical industry is afraid of product piracy. The sector is characterized by beekeepers who find out about the active ingredients and then make home-made illegal concoctions. Awareness and understanding of the current regulation by beekeepers could help to limit/prevent this behaviour.

    Difficulties for research institutes to find financial support because long lasting research is needed without results guaranty.

    Greater interactions between academia/other research organisations and industry may be beneficial.

    A reliable and easy to apply method is needed, especially for the test of the efficacy of certain treatments (within an IPM strategy).

    Not only the number of Varroa mites is important but also the symptoms of the disease (PMS, parasitic mite syndrome).

    However, good beekeeper colony management and husbandry skills are better and needed more than a new test.
  • Vaccines availability

  • Commercial vaccines availability (globally)

    None.

    GAPS:

    Knowledge gap on honeybee immunity.

    There are some approaches (RNAi), however, these approaches represent “high risk research” with doubtful chance for success.

    Also Trans-Generational Immune Priming, TGIP where you “vaccinate” the queen and she transfers immunity to the offspring is a promising technique.

  • Commercial vaccines authorised in Europe

    None.

  • Marker vaccines available worldwide

    None.

  • Marker vaccines authorised in Europe

    None.

  • Effectiveness of vaccines / Main shortcomings of current vaccines

    Not applicable.

  • Commercial potential for vaccines in Europe

    High! Varroa is the main problem for beekeeping worldwide.

    GAPS:

    Uncertainty of innovative research

    So far, no really promising new approach is available, except RNAi.

    Trans-Generational Immune Priming, TGIP where you “vaccinate” the queen and she transfers immunity to the offspring is a promising technique.

    Information on Varroa biology and physiology and host-parasite relationship has been obtained through the SMARTBEES project. However, research is still required.

  • Regulatory and/or policy challenges to approval

    Not applicable.

    General problem of the application of vaccines within the beehive (obviously not for RNAi).

  • Commercial feasibility (e.g manufacturing)

    None. So far, even the first step is lacking.

  • Opportunity for barrier protection

    None.

  • Opportunity for new developments

    Low for V. destructor (high for secondary virus infections).

    GAPS:

    Uncertainty of innovative research.

    The potential of vaccination for PMS (Virus, Bacteria?) should be further evaluated.

    Trans-Generational Immune Priming, TGIP where you “vaccinate” the queen and she transfers immunity to the offspring is a promising technique.

  • Pharmaceutical availability

  • Current therapy (curative and preventive)

    Several types of treatment:

    Regulatory approved products (VMP)

  • 1. Synthetic pyrethroids (mostly used as strips);
  • 2. Coumaphos (trickling and as strips);
  • 3. Amitraz (strips and fumigation). Widely used in the commercial “beekeeping industry”;
  • 4. Organic acids: Formic acid, oxalic acid, lactic acid;
  • 5. Essential oils: mainly thymol-based products, some other substances with potential.
  • The list of regulatory approved products varies from country to country (see Mutual Recognition and Decentralised Procedure-Veterinary).

    Biotechnological methods (beekeeping management strategies: drone brood removal, queen caging + treatment).

    GAPS:

    Limited or no availability of veterinary medicinal products in many countries. However, the cascade system can be used in this case in agreement with the national competent authorities. Imports of medicinal products from elsewhere in the EU or third countries permitted, if the need can be justified.

    The range of veterinary medicine availability depends on country. However, the continued Varroa challenge may not be a result of poor medicine availability, but the lack of correct use or failure to implement IPM strategies.

    Bees are considered to be a ‘minor species’. The MUMS (=Minor Use Minor Species) approach was intended to increase the facilitation for new medicines also for honey bee diseases. Furthermore, a guideline on veterinary medicinal products (in particular on their efficacy and safety) controlling Varroa destructor parasitosis in bees is now available at the EMA .

    The regulatory framework for application for approval of new medicinal products is still considered difficult, time-consuming and expensive at the EU and national levels by companies and beekeepers.

    Mutual recognition is not the easiest way to get more veterinary products in real life.

    Uncertain effectiveness (influenced by brood rearing and climatic circumstances):

  • 1. Synthetic pyrethroids: more information on mode of action and on the dynamic of mite resistant is necessary. “Easy to apply” resistant test is required. Prove whether a “resistance and residue management” with the beekeeper is feasible.
  • 2. Coumaphos: More information on mite resistance is required. Removal of residues from bees wax? Resistance and residue management possible?
  • 3. Amitraz: APIVAR and APITRAZ are available in some EU countries. Ensure that there is wider registration and approval of the products.
  • 4. Organic acid: influence of the temperature and humidity on the efficacy.
  • Future therapy

    Integrated treatment: biotechnical, biological strategies & chemical treatment .

    Avoidance of negative selection of parasites by the use of medicaments: resistant Varroa.

     

    GAPS:

    A better knowledge of the biology and behaviour of Varroa could help to develop new treatments or improve the application of already existing treatments.

    Biological control should be investigated properly.

    Interaction with other stress factors (e.g. environment, beekeeping management) should be integrated in the new treatment development & strategy.

    An integrated Varroa research project should be developed at the EU level through a framework (probably with regional differences, North, Central and South Europe).

  • Commercial potential for pharmaceuticals in Europe

    Limited, because many active ingredients (a.i.) are commercially available at lower costs compared to the authorized medicines. Beekeepers still use the single a.i. instead of the authorized medicine.

    Good (but generic medicaments).

    High, if “easy to apply” and effective.

    However, beekeeping is a difficult market with many hobby and side-line beekeepers with individual ambitions. An exact analysis of the potential of the market is therefore difficult.

    GAPS:

    Authorized veterinary medicines are seldom available and too late in relation to the needs of the sector.

    Industry afraid of a.i. purchased from chemical suppliers when authorised medicinal products are available. This could lead to less profit and higher risk of pharmaco-resistance, damage to the bees and residues.

    Cost for the registration is really high.

    A stand-alone development of a new chemical entity exclusively for Varroa treatment does not seem to be commercially justifiable due to the high investment in toxicological studies etc.

    Encourage chemical testing for Varroa control.

    A more systematic approach for testing chemical products would be an improvement.

  • Regulatory and/or policy challenges to approval

    The registration procedure is considered a challenge for the companies despite the fact that more attention is now devoted to this sector.

    There are many obstacles for the approval of new pharmaceuticals due to the relatively small market; for companies, an investment in the beekeeping industry represents a high financial risk.

    GAPS:

    Shorter procedures should be further considered for this sector (MUMS)

    The registration procedures are well defined: centralized, decentralized, mutual recognition and national. Decentralized/centralised as well as mutual recognition applications will ensure harmonisation across EU Member States. Scientific advice regarding marketing authorisation applications can be sought from national competent authorities or the European Medicines Agency.

    Centralised agreement at the EU-level is recommended.

    Reduce the costs for the procedure to get approved products and/or increase protection periods.
  • Commercial feasibility (e.g manufacturing)

    Yes. Active ingredients are of low cost and the authorized veterinary medicines are not complex.

    GAPS:

    Companies do not consider this sector a priority despite the significant demand from the sector for new medicines.

    Industry afraid of product piracy (limited intellectual property protection/insufficient data protection periods/active ingrediënt already available as plant protection product at lower price).
  • Opportunities for new developments

    Limited, since the companies consider this sector a niche; furthermore new medicines are not based on organic acids and essential oils have always to face pharmaco-resistance and residues in honey bee products;

    RNAi technology could be of interest also in the field of Varroa control as it is for viruses or nosema.

    medium term: low long term: high

    Some interesting ideas exist (biological control with pheromones), however, at the moment they are far away from applications in practice.

    Trans-Generational Immune Priming, TGIP where you “vaccinate” the queen and she transfers immunity to the offspring is a promising technique.

    Development of selection methods for the breeding of Varroa tolerant/resistant honey bees (long-term goal).

    GAPS:

    More research required in this field.

    More research on possibilities and feasibility of biological control is urgently required (control of mite reproduction, mating, host finding).

    More research required on the acaricide resistance mechanisms in Varroa in order to implement a better resistance management.
  • New developments for diagnostic tests

  • Requirements for diagnostics development

    Detection of mite population with a threshold level of damage (e.g. by genetic markers).

    Almost all honey bee colonies in the EU are infested with Varroa mites therefore, quantitative diagnostic tools are required.

    An evaluation of damage thresholds for different regions/ seasons is required.

    Diagnostic tools should fulfil the following requirements:

  • 1. Reliable estimate of infestation rates
  • 2. Easy to apply
  • 3. Standardized
  • Bee pathology, pesticides impact, immunological system.

    GAPS:

    Diagnostics of “PMS” (parasitic mite syndrome) including associated pathogens (bee viruses) could be helpful for the prevention of damages/ timing of treatment independent of infestation level.

  • Time to develop new or improved diagnostics

    3-4 years.

    Depending on money and man/woman-power involved. There should be different approaches for North/Middle/South Europe. Some working groups in Europe are already working on this topic à more cooperation and coordination required.

  • Cost of developing new or improved diagnostics and their validation

    Less than for developing new chemical treatments but still significant. (Fields tests required during several years along and several locations in Europe).

    GAP: The use of easy and cheap active ingredients is also easily copied.
  • Research requirements for new or improved diagnostics

    Genetic markers.

    See section “Time to develop new or improved diagnostics”. The validation of such techniques under controlled conditions should be performed in different climatic regions, at different apiaries (variation of bee colonies, mite population dynamics) and minimum 2 years.

    GAP: Identification of specific genes related to Varroa infestation.
  • Technology to determine virus freedom in animals

    Methods available for the diagnostics of all viruses, but maybe not all validated.

    Biomarkers.

    GAPS:

    There is the need to develop and to validate (new) protocols for the detection and quantification of more bee viruses.

    Identification of biomarkers for honey bees exposed to different viruses.

    More monitoring on the course of infection and pathogenesis of bee viruses required. This is a “young” field of research.

    Specialists on animal viruses (also outside of the honey bee research community) should urgently be involved in such research.

    A better understanding of the microbiome of the bee could offer a new way to interpret the bee health.
  • New developments for vaccines

  • Requirements for vaccines development / main characteristics for improved vaccines

    Development of vaccines: Identification and isolation of Target proteins of V. destructor, Identification of immune-relevant genes in bees.

    Trans-Generational Immune Priming, TGIP where you “vaccinate” the queen and she transfers immunity to the offspring is a promising technique.

  • Time to develop new or improved vaccines

    3-5 years up to 10 years?

  • Cost of developing new or improved vaccines and their validation

    > € 4 million?

  • Research requirements for new or improved vaccines

    Innovative research.

  • New developments for pharmaceuticals

  • Requirements for pharmaceuticals development

    Highly effective; different mode of application for the same molecule; limited side effects on honey bees; limited pollutant effect on honey bee products; no pharmaco-resistance; not dangerous for the user.

    Easy application, reliable high effectiveness, no or low residues in bee products, cheap.

    All applications should be tested under defined conditions à so far, this is not defined in detail.

    New medicine for Varroa treatment. Define the place of the new veterinary medicinal product in the Varroa control strategy.

    GAPS:

    Knowledge about Varroa has much improved during the last 20 years. However, it is still present worldwide (with the exception of Australia). (See also section “Current occurrence/distribution).

    Clear and universally valid definition of tests for efficacy, side effects, work load etc. of new products (and also of some existing applications like formic acid).

    EU guidance available at EMA .

    Most applications are limited for the use outside the period of the honey flow (which is, at the same time, the period of increased mite population) due to the risk of residues in honey à applications during the brood season are available depending on the active ingredient (even with lower efficacy if compared with treatment during brood less periods).

    Develop an integrated system: integrate the biological aspects of the colony and the Varroa-population with the use of chemicals in order to reduce the use of chemicals.

    New compounds with new modes of action.

    Feasible benefit risk assessment (residues in honey, honey market requirements, risk for the user). Persistent acaricide residues in beeswax are a problem.

  • Time to develop new or improved pharmaceuticals

    4-5 years was the time length in the 80s.

    Improvement of existing applications (especially on organic acids and essential oils) could be done within 3-5 years.

    10 to 15 years if the research starts from scratch today.

    GAP: A more intensive cooperation with respective companies as well as academia is required for new acaricides (and new active compounds).
  • Cost of developing new or improved pharmaceuticals and their validation

    New compound: € 30 - 50 million.

    New pharmaceutical (formulation) compound: few million euro.

    Clinical development & regulatory approval: few million euro.

    GAPS:

    A different model is needed: cost sharing.

    The new compounds discovered by the scientific community should be systematically tested for Varroa treatment.

    Create an awareness for the Varroa market for the decision making of developing new treatment.
  • Research requirements for new or improved pharmaceuticals

    Screening of substances, new application methods:

  • 1. Mite biology/ physiology
  • 2. More detailed knowledge on population dynamic
  • 3. Damage thresholds (see above)
  • “Strategy” of use: time of the year, bee density, colony strength, climate, virus population.

Disease details

  • Description and characteristics

  • Pathogen

    Varroa destructor (Anderson and Truman, 2000), mite (Mesostigmata: Varroidae).

    Several bee viruses which are only pathogenic if Varroa mites are involved. Varroa mites transmit and activate certain viruses.

    GAPS:

    All viruses are not known.

    The importance of interaction and transmission between Varroa and other non-viral infections is not fully known.

  • Variability of the disease

    Varroa destructor in Europe, America.

    Varroa jacobsoni in Asia.

    Different haplotypes.

    Varroa types with differences in virulence identified (e.g. Korean, Japan haplotypes), pesticide resistant strains, different virulent virus strains (e.g. DWV more virulent after multiplication in the parasite).

    Different genotypes/ haplotypes available, however in Europe obviously only one “virulent” haplotype present.

    GAPS:

    Cooperation between the original location of Varroa (Asia) and Europe should be better developed.

    The statement of 8.2. has to be confirmed with more and long-term data/ samples. Proof of pathogenesis of different Varroa haplotypes.

    The factors of virulence of different Varroa strains are unknown.
  • Stability of the agent/pathogen in the environment

    Obligate parasite, cannot survive without the host.

    Cannot survive without honeybees more than 2 weeks.

  • Species involved

  • Animal infected/carrier/disease

    Reproduction only on honeybees Apis mellifera and Apis cerana (in wasps a rare vagrant).

  • Human infected/disease

    None.

  • Vector cyclical/non-cyclical

    No. Can not survive without honeybees for more than 2 weeks.

  • Reservoir (animal, environment)

    No.

  • Description of infection & disease in natural hosts

  • Transmissibility

    Yes, from bee to bee and drifting.

    Yes, from colony to colony. Cases of re-infestation from collapsed colonies to strong, robbing colonies. Re-infestation possible soon after a treatment.

    Can be easily transmitted between colonies of the same apiary and transmitted over the flight range (2-3 km) through robbing, swarming or drifting.

    Transport of colonies, migratory beekeeping & beekeeping management practices.

    GAP: More work on re-infestation should be carried out.
  • Pathogenic life cycle stages

    Brood infestation (Varroa reproduction occurs at this stage within capped brood cells), adult bee infestation.

    All ontogenetic stages of the mite (protonymph, deutonymph, adults) are haematophagous.

  • Signs/Morbidity

    Clinical signs detectable in case of severe infestation (PMS).

    Mainly symptoms of the associated bee viruses (DWV, ABPV, CBPV); weakening of the colony.

    GAPS:

    Differentiation of the effect of damages by the parasite itself and the associated bee viruses is difficult.

    We need a tool to measure and discriminate the origin of the symptoms (Varroa or viruses).
  • Incubation period

    Varroosis: 1 year (1 beekeeping season).

    From first infestation to mortality 1-3 years (depending on invasion pressure and virus levels).

  • Mortality

    Almost 100% if not properly treated.

  • Shedding kinetic patterns

    Not applicable.

  • Mechanism of pathogenicity

    Haemolymph deprivation, co- infections (virus)

    Loss of haemolymph, mainly during the ontogenetic development of the bee à weakening of immune system à weakening of the colony à damages/collapse.

    Loss of haemolymph reduces the lifespan of the bees and the reproduction success of the drones.

    GAPS:

    Interaction with stress factors such as other pathogens and toxic substances, environmental conditions (nutrition availability), climate, colony behaviour.

    Definition of the “tipping point” between damage of individuals and visible/measurable damage of the colony as superorganism.
  • Zoonotic potential

  • Reported incidence in humans

    None.

  • Risk of occurence in humans, populations at risk, specific risk factors

    None.

  • Symptoms described in humans

    None.

  • Estimated level of under-reporting in humans

    None.

  • Likelihood of spread in humans

    None.

  • Impact on animal welfare and biodiversity

  • Both disease and prevention/control measures related

    No impact on vertebrate animals.

    Impact on floral biodiversity & sustainability.

  • Endangered wild species affected or not (estimation for Europe / worldwide)

    No impact on wild bees (other than honeybees).

    Potential impact on wild floral biodiversity & sustainability.

    GAP: Limited knowledge on the true impact of Varroa on wild bee species, if any.

  • Slaughter necessity according to EU rules or other regions

    In the EU no instructions on the destruction of infested honeybee colonies. Treatment is recommended.

    According to Italian veterinary regulation revised in 2013 in case of severe infestation with evident clinical signs and lack of proper management, destruction of the colony is applicable.

    GAP: According to the characteristics of the infestation a harmonization of the rules is recommended.

  • Geographical distribution and spread

  • Current occurence/distribution

    Worldwide, except Australia and some parts of Oceania, Europe (north of Sweden, Åland Islands, Isle of Man, Ile de Ouessant), central Africa.

  • Epizootic/endemic- if epidemic frequency of outbreaks

    Panzootic parasitic disease, well established parasite.

    Now endemic to Europe.

  • Seasonality

    High mortality late in season and in Winter.

    Population growth from spring to autumn à colony damages mainly in autumn/winter due to general population decrease in colonies before winter and sensitivity of long-living winter bees.

  • Speed of spatial spread during an outbreak

    Present in all colonies but re-infestation is a key point.

    Spread is linked to honey bee (adult or brood) movement (natural or human managed).

    Cases of re-infestation from collapsing to strong, robbing colonies.

    High via disoriented and drifting bees.

  • Transboundary potential of the disease

    High.

    Already worldwide distribution (except Australia), limitation of spread nearly impossible.

  • Seasonal cycle linked to climate

    Infestation increase during the honey bee brood rearing period (from spring to autumn in temperate climates). Climate influence the brood rearing (the population dynamics).

  • Distribution of disease or vector linked to climate

    Temperate climate is optimal for both the honey bees and Varroa.

    Parasite reproduction depends on brood rearing of bees influenced by climate.

    Depend on the activity of the bee colony.

  • Outbreaks linked to extreme weather

    None.

  • Sensitivity of disease or vectors to the effects of global climate change (climate/environment/land use)

    Bees are affected by weather conditions, therefore the parasite is affected by climate through an indirect effect.

    Low temperature reduces honey bee activity and brood, as a consequence also the Varroa load is reduced.

    High.

    More problems in warmer (Southern Europe) climate because of the availability of bee brood throughout the year. Climate change might have a slightly negative impact due to the reduction of brood free periods of honey bee colonies in some European regions.

    The control of Varroa with some products is more critical in Southern Europe due to high temperature during summer making treatment with volatile compounds more difficult and the absence of brood-free period during winter. Climate changes could make the problem bigger in the future.

    GAP: In the tropics, varroosis is only a minor problem. The reasons for this balanced host-parasite-relationship are still unknown.
  • Route of Transmission

  • Usual mode of transmission (introduction, means of spread)

    Migration of bee colonies, disoriented bees. Viruses via bees and mites.

    Between colonies/between apiaries à robbing, movement of bees and material by beekeeper.

    GAP: Methods for the beekeeping practice to reduce transmission of mites (quantitative data particularly).
  • Occasional mode of transmission

    None.

    Merchandising of honey bee colonies (worldwide).

  • Conditions that favour spread

    Beekeeping management: trade, robbing, drifting.

    Ineffective Varroa control.

    Bee colonies dying of high mite population, disoriented bees.

    Bee density and average infestation rates are the main driver for transmission rates.

    GAP: The quantitative effect of drift is unknown.

  • Detection and Immune response to infection

  • Mechanism of host response

    Limited knowledge.

    Untreated colonies (the “Bond test”: live or let die).

    Suppression of innate humoral immune system of the host by (i) introduction of salivary gland secretion into the puncture site and (ii) transmission of bee viruses.

    GAPS:

    More information needed about host-parasite interaction.

    Immune respond is almost a black box (individual – honeybee level and colony level).
  • Immunological basis of diagnosis

    Not available.

    “DNA-Chip” for Virus diagnostic (EU-project BEEDOC).

    GAP: Tools should be available to measure immunological status of honey bee and subsequent disturbance by stress.
  • Main means of prevention, detection and control

  • Sanitary measures

    Regular treatment.

    Colony movement only with low infested colonies.

    GAP: Control strategies need to be harmonized.

  • Mechanical and biological control

    Beekeeping techniques need to be combined with medicament treatment.

    Biotechnical control is available: splitting of colonies, trapping Varroa in brood, brood removal (drone, or prevent the queen from egg laying).

    GAPS:

    So far, no biological control available.

    Biotechnical control should be improved according to geographical locations of beekeeping.

  • Diagnostic tools

    Natural mite mortality, infestation of adult bees.

    GAP: Predicting the need of control (treatment), check the effectiveness of the control measures.
  • Vaccines

    Not applicable.

  • Therapeutics

    Medicaments (essential oils, organic acids, synthetic substances).

    GAPS:

    Treatments are complex. There is some concern about Varroa resistance. More treatment options should be developed. Hive management should be improved (beekeeper skills).

    The efficacy of some Varroa control strategies is climate dependant to some extent. Therefore, the knowledge of beekeepers should be increased on a year to year basis.

  • Biosecurity measures effective as a preventive measure

    Honey bee movement restriction was not able to prevent Varroa spreading.

    It is known that bees from dying colonies spread mites. Therefore, the treatments should be coordinated at a regional level.

    GAPS:

    Lack of awareness of the importance of the Varroa infestation level (above a threshold).

    The treatments should be efficiently coordinated at a regional level.

    A monitoring of the infestation-rate at regional level could be helpful to aware the beekeepers about the need of treatments.
  • Border/trade/movement control sufficient for control

    All colonies are infested but in a controlled area, diseased colonies should not be moved.

    GAPS:

    Regulation is lacking on diseased colonies that should not be moved.

    Specific EU regulations on colony movement do exist to protect Varroa-free territories.

  • Prevention tools

    None.

    GAP: Information to beekeeper should be better organised (disease alerts) at a local scale and promoted at a European level.

  • Surveillance

    No, Varroa is distributed worldwide (except Australia).

    Predicting the need of control (treatment).

    In some national/regional monitoring/surveillance programs Varroa is involved (German bee monitoring). The veterinary services analyse several samples per year (mostly from collapsed or damaged colonies).

    GAPS:

    However, a long term extensive surveillance following standardized protocol is still lacking.

    A good hive or beekeeper registration should be applied in each EU country (National beekeeping registry). Recordings of movement should also be in place.

  • Past experiences on success (and failures) of prevention, control, eradication in regions outside Europe

    No eradication experiences available; Varroa is considered a minor problem in South America with Africanized bees; means of control are similar to those applied in Europe with similar success and failure experience; climate conditions could affect the level of infestation and the effectiveness of control measures.

    Varroa was among the causes of Colony Collapse Disorder (CCD) in US, no effective treatment available; border control (bee free areas) North America.

    Some efforts have been made in Eastern and Northern Europe 20-30 years ago (for instance in Czechoslovakia), at the time when Varroa arrived. Very little success.

    GAP:

    For effective control of Varroa: several problems: registered acaricides available but their efficacy depends on several factors, i.e. colony strength, climate, mode of application, colony management, need for tools to measure efficacy and impact on honeybee biology.

  • Costs of above measures

    The economic impact of good control and surveillance system is crucial.

    Varroa treatment per hive per year is minimum € 5. There are 15 million colonies in EU. Total costs: € 75 million.

    20% of colonies are lost every year due to mainly Varroa. € 200 to replace a colony= € 600 million per year.

    GAP: Cost should include colony replacement, lack of harvest and pollination services. How can we estimate the cost of the lack of biodiversity?
  • Disease information from the OIE

  • OIE disease card available

    No. 

  • Socio-economic impact

  • Zoonosis: impact on affected individuals and/or aggregated DALY figures

    Not applicable.

  • Zoonosis: cost of treatment and control of the disease in humans

    Not applicable
  • Direct impact (a) on production

    Yes, bee colony losses could be due to Varroa infestation if not properly treated/managed.

    20% of colonies are lost every year considered mainly due to Varroa. € 200 to replace a colony = € 600 million per year.

    Pollination fees

    Honey production: 160 thousand tons per year in EU. Mean honey price is € 6 / kg. Loss of 20% of the colony = 32 thousand tons = € 192 million.

    Current UK price for honey in bulk is about £ 6 per kg = 8 Euros.

    There is a shortage of beeswax (for pharmaceutical, food, apiculture sector): the demand is higher than the production. Prices have doubled in the past 2 years.

    GAP:

    The honey distributed on private/local networks is not taken into account in cost estimations, and the additional workload for livestock recovery as well.

  • Direct impact (b) cost of private and public control measures

    Varroa treatment per hive per year is minimum € 5; € 4-10 according to More et al. (2017). There are 15 million colonies in the EU. Total costs: € 75 million.

    20% of colonies are lost every year due to mainly Varroa. € 200 to replace a colony = € 600 million per year.

    EU invests € 32 million each year for helping the beekeeping sector = € 64 million in total (top up of 50% financial help for each member state).

    GAP: Costs of state surveillance programs should be included.

  • Indirect impact

    Reduction and/or disruption of honey production.

    Lack of pollination of wild plants and agricultural plants.

    Organic honey producers have difficulties to control Varroa, and experience subsequent decreased honey production.

    Decrease of number of beekeeper à fewer colonies for pollination.

    Tropical apiculture has less problems with Varroosis à advantage for honey production.

    GAPS:

    There are difficulties to assess the extent of these impacts. There are also difficulties to assess the costs of these impacts.

    Honey bees are generally considered to be major pollinators, essential for optimal crop and fruit production but data on their relative contribution versus other pollinating insect species is limited.

    Loss of genetic diversity in honeybee (e.g. breeding programmes).

  • Trade implications

  • Impact on international trade/exports from the EU

    No big impact because of world-wide distribution of Varroa mites.

  • Impact on EU intra-community trade

    Limited, since Varroa is present in all EU countries (Varroa is worldwide distributed except Australia), but Åland Islands (FIN) and Isle of Man (UK) are officially Varroa-free territories within the EU.

  • Impact on national trade

    None.

  • Main perceived obstacles for effective prevention and control

    Limited availability of medicines; poor treatment strategies; need to integrate beekeeping techniques with medicine treatment

  • 1. Varroa represents still the number 1 management problem for beekeepers worldwide who have to manage this pest;
  • 2. Beekeeper knowledge on Varroa control to some extent;
  • 3. Limited availability of effective and “easy to apply” control methods;
  • 4. Common recommendations of veterinary/extension services, at least for some state, is often lacking or insufficient or are poorly followed by beekeepers;
  • 5. The available diagnostic methods are not satisfactory.
  • GAPS:

    Treatment application by beekeepers, beekeeper skills in the use of diagnostics and medicament.

    Apicultural organisations should be more involved in the beekeeper training systems.

    Accessibility of the POM (Prescription Only Medicine): a vet must prescribe the medicament. Beekeeper groups can ask for a common prescription in some EU countries. This should be applied in all EU countries when possible.

    However, there are medicines available on general sale in the UK and other member states (e.g. Italy) without the need for a veterinary prescription.

    Consideration should be given to exempting bee medicine from the POM regime or should be taken out of the POM regime.

    National regulations on veterinary medicinal products are not harmonized, differences do exist among Member States.
  • Main perceived facilitators for effective prevention and control

    The presence of Varroa in the beehive is easily detected by beekeepers.

    GAPS:

    Clear recommendations are needed.

    Better training for veterinaries and apiarists to provide better information and knowledge on residues and resistance’s risk.

    A better system should be developed to associate beekeepers, associations and vets = integrated strategy.

Risk

  • Colony losses directly related to Varroa infestation not properly controlled. Decrease in honey bee populations and beekeepers. Increasing dependency on honey and beeswax imports and other honey bee products.

    Loss of genetic diversity in honey bee.

    Loss of important pollinator with impact on crop production and plant diversity.

Conclusion

  • Varroa represents an extremely dangerous pest with limited availability of effective and easy-to-apply control methods. The available diagnostic methods are not satisfactory. The active ingredients used for the control of Varroa mite infestation have been identified already 25-30 years ago, both synthetic like amitraz, bromopropylate, cymiazole, coumaphos, tau-fluvalinate, flumethrin, and “natural” like organic acids and essential oils. Most of them were derived from agriculture and adapted for controlling Varroa infestation. Since then the improvements were concentrated on improved formulation of active substances, improved mode of administration, removal from the market of those too pollutant and integrated control strategies (IPM). The revision of the EU regulation on veterinary medicinal products accompanied this process. Despite the increased availability of veterinary medicinal products (many of them with the same active substance, e.g. formic acid, oxalic acid, amitraz, thymol, coumaphos), treatment strategies overall are poor and need to be integrated with improved beekeeping management strategies. In addition, common recommendations for diagnosis and control by veterinary/extension services is often lacking, are poorly followed by beekeepers or has insufficient coverage of the territory.

Sources of information

  • Name of expert group leader

    Franco Mutinelli, National Reference Centre for beekeeping, Istituto Zooprofilattico Sperimentale delle Venezie, Italy - [Leader]

    Marie-Pierre CHAUZAT, EU Reference Laboratory for honey bee health, ANSES, France

    Eva Forsgren, National Reference Laboratory for honey bee health, Swedisch University of Agriculture, Sweden

    Mike Brown, Animal & Plant Health Agency (APHA), National Bee Unit, UK

  • Date of submission by expert group

    31 December 2017.

  • References

  • Name of reviewers

    Project Management Board.