New technology finds pathogens that may reconcile contradictory claims on Colony Collapse Disorder

by JAMES FISCHER

James Fischer (james.fischer@gmail.com) for
“The American Bee Journal”  (http://www.americanbeejournal.com)
(Embargoed by the journal PLoS ONE until 10/06/2010 5pm EDT)

A multi-institutional team of researchers sifted through the ever-growing zoo of new invasive, exotic pathogens of bees, and consistently found the same two disease organisms in beehives suffering from Colony Collapse Disorder (CCD) in samples collected from 2006 to 2009.

They discovered a new virus never seen before in North America, and found a well-known invasive variant of the intestinal bee disease Nosema. The overlooked virus may explain why prior studies presented mutually contradictory findings. This new evidence could create a basis for consensus among research teams who to date, lacked common ground in their conclusions.

Their paper appeared only minutes ago in the journal PLoS ONE (http://dx.plos.org/10.1371/journal.pone.0013181)

The paper reports on a multi-year study of Colony Collapse Disorder. Researchers used new technology and techniques to detect and unambiguously identify every pathogen in collapsing bee hives, rather than the smaller subset of possible pathogens detectable via other means.

An Invertebrate Iridescent Virus (“IIV”) , newly-found in North America, in combination with Nosema ceranae, which arrived from overseas less recently, was found in “Virtually all of the bees from CCD colonies” sampled from widely dispersed USA hives from 2006 through 2009.

IIV was not found in bees from packages imported from Australia nor in bees from an isolated non-migratory commercial bee operation in Montana, both sites confirmed free of CCD-like symptoms.

Additionally, the researchers “observed the progression of CCD in a collapsing colony… taking bee samples… over a three month period, ending when only a queen and four workers remained.”

Further still, some bees were inoculated with Nosema ceranae, while other bees were inoculated with the “IIV-6” strain of the IIV virus. Their mortality was then compared to bees inoculated with both pathogens, and a control group given a placebo. The results “strongly suggest that the combination of N. ceranae and IIV is associated with increased bee mortality.”

Yet even further, the effort discovered two additional invasive exotic bee viruses never before detected in North America, but determined that they were not involved in CCD.  The viruses found are “Varroa Destructor-1 Virus” and “Kakugo Virus”, both native to Asia.

Dr. Jerry Bromenshenk of U Montana outlined the next steps, “We have a proposal pending to isolate, characterize, and then inoculate bees with the specific iridescent virus that occurs in USA bees. This is a critical step, since the virus does not appear to be any of the world’s known iridescent viruses. Once we have the actual virus, we can complete the inoculation trials that are needed to test whether we’ve truly found the cause of CCD.”

Proteomics – A Brief Summary
The technology used in this study seems ideal for addressing the ever-growing list of pathogens carried across oceans by the globalization of trade. It can detect disease pathogens that need not be identical to any known pathogen. This describes the needs of beekeepers clearly, given the number of invasives that came to plague honey bees in the USA since the early 1980s.

“Mass Spectrometry-Based Proteomics” (MSP) starts with about 60 bees tossed in a blender, and mixed until homogenous, then filtered. Cells are chemically burst, and proteins are isolated from the mix and “digested”, breaking them down to peptides.  The resulting peptides are run through a device called a “Liquid Chromatograph” to separate them by density, which allows their structure and sequence to be determined by another set of devices, “Tandem Mass Spectrometers”.

Each peptide sequence is then compared to the NIH National Center for Biotechnology (NCBI) database of peptide sequences.  The database used is a collection of the peptides unique to specific organisms. This means that each match of a peptide sequence is a unique match to a single organism. Any peptide used in more than one organism would not be in the database.

Dr. Charles Wick of the US Army Edgewood Chemical Biological Center explained the level of certainty with which the virus was detected in colonies showing CCD symptoms: “IIV has 18,900 unique peptides… When we detect a few of these, say 50-100, we have enough evidence for an unambiguous identification.”

But how did they make what Dr. Wick called an “unambiguous identification” of a virus that was said by Dr. Bromenshenk to not be “any of the world’s known iridescent viruses”? How can anyone find what’s never even been detected or identified before?  The answer is that the unknown organism will match the closest organism in the database, which narrows things down to at least the “family” or “genus” level, if not “species”.  So, even without having sequenced the specific strain of IIV of interest, enough peptides matched the IIV strain in the database to confirm that what was found was a strain of IIV.

As an example of the wide net cast by this technique, Nosema was not well-represented in the NCBI database, so there was some ambiguity in the identification of the Nosema via proteomics alone, matching only the genus Nosema. The species and strain was confirmed as Nosema ceranae using Polymerase Chain Reaction (PCR) techniques.

The Claims In Spain Can Mainly Be Explained
Research led by Mariano Higes of the Bee Pathology Laboratory, Centro Apícola Regional in Marchamalo, Spain has repeatedly pointed to Nosema ceranae as the sole proximate cause of rapid colony collapse.  This seemed unlikely to researchers in the USA and elsewhere, as Nosema has not appeared to be as virulent outside of Spain.  But this new work provides an explanation that could support the Higes work with nothing more than the addition of the newly-detected IIV.

As in previous US studies, no one in Spain would have had reason to suspect that a DNA virus like IIV would be involved, as the bulk of bee viruses are RNA viruses. So they’ve yet to look for IIV in Spain, and they have not had the wider net of MSP to find what was not being sought. The good news is that Dr. Higes has historical samples frozen. Dr. Jerry Bromenshenk reports that the Higes team is willing to engage in a joint effort to screen the Spanish samples using MSP.

Does This Explain CCD In The USA?
The samples analyzed in this study showed a wide range of pathogens, including Nosema, Invertebrate Iridescent Virus (“IIV”), Black Queen Cell Virus, Acute Bee Paralysis Virus, Israeli Acute Paralysis Virus, Deformed Wing Virus, Sac Brood Virus, Kashmir Bee Virus, Varroa Destructor-1 Virus, and Kakugo Virus. None of the suspect pathogens named by other research efforts were missed, two new and novel pathogens were found, and the use of MSP implies that no pathogens were overlooked.  Even a new, unknown, and unnamed pathogen would have resulted in a partial peptide match to some other living thing.

So, while the counts or mix of pathogens might have been skewed by an insufficient number of samples, or collecting samples from an insufficient number of operations, it is difficult to imagine that there are additional pathogens yet to be found that could be implicated in CCD.

Insecurity About Biosecurity
Since the 1980s, “Globalization” has increasingly consisted of shipments of goods from Asian ports to Western shores. This research connects the dots by consistently finding specific bee pathogens native to Asia, unknown to USA beekeepers in the early 1980s, but that have since become far too familiar:

“We know that in the Asian honey bee, Apis ceranae, a combination of parasites and pathogens co-exist, including: (1) Nosema ceranae, (2) an iridescent virus, (3) parasitic and predacious mites, and (4) two other RNA-type viruses, Kashmir bee virus and a Sacbrood virus.  We have had both Kashmir bee virus and Nosema ceranae in North America going back a decade or more. We need to see how similar the CCD strain of iridescent virus is to the IIV-24 strain from Apis ceranae.  It is possible that US bees acquired IIV from the Apis ceranae along with Nosema ceranae and Kashmir bee virus.” 

While unsubstantiated “fringe” explanations for CCD abound, ranging from cell phones to pesticides to GMO crops, the common factor is that pathogens previously found only in Asia have spread to countries lacking effective biosecurity, such as the USA, but not to countries with more robust approaches to biosecurity, such as New Zealand.  The research team suggests “Standard quarantine practices such as testing of imported bees before they are added to colonies, and disinfection of equipment would likely help.”

Practical Implications For Beekeepers
The team has two suggestions of interest to beekeepers:

1. “Most IIVs replicate at about 21 C (70 F) and do not replicate above 30-32 C (86 – 89 F). Higher temperatures may suppress the virus by halting replication, whereas cool weather and damp conditions may speed up replication of both IIV and Nosema. Many instances of CCD have occurred following extended periods of cool, damp weather.  Several beekeepers have reported to us that they have more problems with bees in areas with frequent fog or in hill areas where the weather is cooler. Placing bees in warm, sunny locations appears to help.”
2. “Varroa may act as a vector for the dispersal of IIV among bee colonies. Varroa is known to increase damage caused by other viruses, and beekeepers who fail to control varroa levels are likely to sustain high colony losses.”

This may not sound like much, but it is a vast improvement over the usual vague platitudes we’ve been handed over and over about “maintaining strong colonies” and “minimizing stress”. It also ups the ante in the age-old debate among beekeepers over placing hives in sun versus placing hives in shade.

“Iridovirus and Microsporidian Linked to Honey Bee Colony Decline”
Jerry J. Bromenshenk, Colin B. Henderson, Charles H. Wick, Michael F. Stanford, Alan W. Zulich, Rabih E. Jabbour, Samir V. Deshpande, Patrick E. McCubbin, Robert A. Seccomb, Phillip M. Welch, Trevor Williams, David R. Firth, Evan Skowronski, Margaret M. Lehmann, Shan L. Bilimoria, Joanna Gress, Kevin W. Wanner, Robert A. Cramer Jr.

(2010) PLoS ONE 5(10): e13181. doi:10.1371/journal.pone.0013181

Jim Fischer keeps bees in Manhattan, Brooklyn, and the Bronx, and hopes to raise queens in Queens. He teaches the free 16-week full-semester urban beekeeping class in New York’s Central Park for the 846-member non-profit NYC Beekeeping Group (http://meetup.com/nyc-beekeeping)  and helps run the Gotham City Honey Co-Op (http://GothamCityBees.com).

More evidence. I’m happy to elevate these articles to higher readership. -DNR

http://environmentalresearchweb.org/cws/article/news/43568

Aug 27, 2010

Insecticide implicated in bee decline
Honeybees, bumblebees and many other insects are being slowly poisoned to death by persistent insecticides used to protect agricultural crops. Small doses of the toxic chemicals accumulate over time, meaning that there is no safe level of exposure. That’s the conclusion from recent research looking at the long-term effects of a commonly used class of insecticides.

As they buzz from flower to flower, bees, moths and hoverflies carry out a vital job. Around one third of agricultural crops are pollinated by these busy insects, a service that is worth £440 m a year to the UK economy alone.

But in recent years these valuable pollinators have been struggling, with populations plummeting worldwide. Honeybees in particular have been suffering, with colony collapse disorder (CCD) – a phenomenon where the bees desert the hive – becoming more common in Europe and North America.

Controversy has swirled around the issue, and everything from mobile phones to GM crops have been blamed. Now new studies indicate that insecticides are playing a significant role.

The most recent studies have exposed a variety of insects to varying doses of neonicotinoid insecticides over long time periods – 12 months or more. Neonicotinoid insecticides are widely used worldwide; they work by acting on the central nervous system of the insect. The chemicals have little affinity for vertebrate nervous systems, so they are much less toxic to mammals and birds.

The researchers found that the total dose of insecticide required to kill the insect was smaller if administered over a longer time period (Ecotoxicology (2009) 18:343–354). In the case of honeybees, up to 6000 times less insecticide was required to kill them if it was administered in multiple tiny doses over a long time period.

According to Henk Tennekes, a researcher at Experimental Toxicology Services (ETS) in the Netherlands, these findings make perfect sense. “Start by considering a high exposure level,” he said. “It may cause an early effect, such as cancer or mortality. At a much lower exposure level you may get a late effect. However, as it turns out, in the latter case you need much less of the stuff (in total) to produce the effect.” Tennekes describes the findings in a forthcoming paper in Toxicology.

So how do these insecticides achieve such a powerful long-term effect? The answer lies in the way that they work. Neonicotinoids bind irreversibly to receptors in the central nervous system of insects. “An insect has a limited amount of such receptors,” explained Jeroen van der Sluijs, a scientist at Utrecht University in the Netherlands, who has also worked on the problem. “The damage is cumulative: with every exposure more receptors are blocked until the damage is so big that the insect cannot function anymore and dies.”

Even small doses over a short time period can cause serious problems. At low doses insects have been observed to become disorientated and less co-ordinated in their movements, making them easier prey for predators. Sub-lethal effects such as this weaken the insect; they particularly jeopardize social insects, which depend on the entire colony being healthy for survival.

Right now it still isn’t possible to say if neonicotinoids are the sole cause of CCD in honeybees, but it seems likely that they play a significant role. “It explains the rapid increase in CCD since 2004, which coincides with the rapid growth in worldwide use of neonicotinoids – the most widely used class of insecticides,” said van der Sluijs.

Currently the insecticides are commonly used to coat seeds, regardless of whether there are many insect pests or not. They leach easily into soil and water and are taken up readily by plants, making the entire plant toxic to insects. And as the new research shows, even at very low levels they have the potential to cause huge damage to insect populations. “I think these insecticides need to be replaced by less long-lived alternatives that are less toxic to honeybees and less prone to leaching,” said Tennekes.

About the author

March 30, 2010 -The United States Department of Agriculture (USDA) Agricultural Research Service, in conjunction with the Apiary Inspectors of America, is conducting a voluntary survey to determine the bee colony losses for the 2009/2010 winter.  This survey is not just for beekeepers with huge numbers of hives, even small-scale beekeepers are encouraged to participate.  The survey takes approximately two minutes, and is completely anonymous.

Data collection efforts such as this may be crucial to understanding bee-related diseases that affect colonies, including colony collapse disorder. The scope of this problem may be poorly understood. According to Peter Borst, a former New York State apiary inspector, no one really knows how many beehives are out there. USDA estimates of 2.6 million bee colonies in the US are derived from national surveys and farm surveys that don’t count the thousands of small apiaries (fewer than five hives)

managed by hobby beekeepers. Based on Borst’s local knowledge, as many as 90% of the local beekeepers may have elected to not register with the state — which is where the national surveys start for the data.

The more beekeepers who participate, the more data the USDA has to work with, which may help researchers get closer to understanding a perplexing problem in our agricultural world. Dr. Jeff Pettis, Research Leader at the USDA-ARS Bee Research Laboratory, notes that last year they surveyed beekeepers who managed about half a million colonies.  Pettis hopes this year’s response to be even greater. 1

If you know a beekeeper with one hive or one hundred, share this information with them.  Good research requires good data.

———————————————————————————————————–
Dear Beekeeper:

The Apiary Inspectors of America and the USDA-ARS Beltsville Bee Research Laboratory are seeking your help in tabulating the winter losses that occurred over the winter of 2009-2010. This continues the AIA/USDA survey efforts from the past 3 years which has been important in quantifying the losses of honey bees for government, media, and researchers.

This year’s survey is faster, easier and does not require your time on the phone. It is all web based and automatic, just fill and click.

Please take a few moments to fill out our winter loss survey at: http://www.surveymonkey.com/s/beeloss0910

This survey will be conducted until April 16th, 2010.

We would also appreciate it if you would forward this email to other beekeepers. The more responses the better.  If you have any questions or concerns please email beeloss@gmail.com, or  Honeybee.Survey@aphis.usda.gov.

Thanks in advance for your assistance.

Jeff Pettis; USDA-ARS Beltsville Bee Research Laboratory
Dennis vanEngelsdorp; Penn State University
Jerry Hayes; Florida Department of Agriculture
Dewey Caron; University of Delaware and Oregon State University

What would Rachel Carson say to this story? The business publications are an echo-chamber of headlines reading “procedural issues” were what made spirotetramat illegal to sell, while other blogs and newspapers focus of the press release’s spin (harm to bees). The monopoly market publications would like to tell their readers/advertisers that it wasn’t banned because of proven harm to the pollinators and ecosystems (the same ecosystems that support the damned economy in the first place), no no… it was banned because the EPA and BayerCrop Science broke the laws, a.k.a. “procedures,” and got busted!  Why don’t they say “legal issues lead to ban of pesticide” or “secret law breaking discovered, leads to pesticide ban” or “NRDC and Xerces were watching while we tried to sell poison without EPA/public approval and they blew the whistle on behalf of science and public laws designed to protect the People from the Corporation”? (see evidence of eco-chamber) This story reveals the fraud and deceit that is Bayer CropScience and revolving door EPA cronies. It’s so easy to sell their poison and bio-warfare in China and Brazil, because those countries don’t have public oversight like the U.S.A. has with the EPA - Environmental Protection Agency. It’s time to review and renew our appreciation and understanding of our EPA. This story is really about the Xerces Society and National Resource Defense Council forcing the EPA to follow its own rules and public protection “procedures.” Had it not been for them, the EPA and Bayer CropScience would have simply violated the law in secrecy and ineptitude, exactly what Bare CrapScience wants to see happen, IMHO.Important to note that well-known commercial beekeepers Dave Hackenberg (and Dave Mendes?) worked with Bayer CropScience to field test the effects of spirotetramat on honeybees in Florida.  Click image for PDF of report.Here’s a nice footnote from the Judge Cote’s ruling:

 It is undisputed that the plaintiffs have standing to bring this case.  See Connecticut v. Am. Elec. Power Co., 582 F.3d 309, 339 (2d Cir. 2009) (“An association has standing to bring suit on behalf of its members when: (a) its members would otherwise have standing to sue in their own right; (b) the interests it seeks to protect are germane to the organization’s purpose; and (c) neither the claim asserted nor the relief requested requires the participation ofthe lawsuit.” (citation omitted)).

Judge Pulls Pesticide After Finding Impacts on Bees Inadequately Evaluated by EPA(Beyond Pesticides, January 4, 2010) – A pesticide that could be dangerously toxic to America’s honey bees must be pulled from store shelves as a result of a suit filed by the Natural Resources Defense Council (NRDC) and the Xerces Society. In an order issued in December, a federal court in New York invalidated EPA’s approval of the pesticide spirotetramat (manufactured by Bayer CropScience under the trade names Movento and Ultor) and ordered the agency to reevaluate the chemical in compliance with the law. The court’s order goes into effect on January 15, 2010, and makes future sales of Movento illegal in the United States.“This sends EPA and Bayer back to the drawing board to reconsider the potential harm to bees caused by this new pesticide,” said NRDC Senior Attorney Aaron Colangelo. “EPA admitted to approving the pesticide illegally, but argued that its violations of the law should have no consequences. The Court disagreed and ordered the pesticide to be taken off the market until it has been properly evaluated. Bayer should not be permitted to run what amounts to an uncontrolled experiment on bees across the country without full consideration of the consequences.”In June 2008, EPA approved Movento for nationwide use on hundreds of different crops, including apples, pears, peaches, oranges, tomatoes, grapes, strawberries, almonds, and spinach. The approval process went forward without the advance notice and opportunity for public comment that is required by federal law and EPA’s own regulations. In addition, EPA failed to evaluate fully the potential damage to the nation’s already beleaguered bee populations or conduct the required analysis of the pesticide’s economic, environmental, and social costs.Beekeepers and scientists have expressed concern over Movento’s potential impact on beneficial insects such as honey bees. The pesticide impairs the insect’s ability to reproduce. EPA’s review of Bayer’s scientific studies found that trace residues of Movento brought back to the hive by adult bees could cause “significant mortality” and “massive perturbation” to young honeybees (larvae). According to the U.S. Department of Agriculture (USDA), bees pollinate $15 billion worth of crops grown in America. USDA also claims that one out of every three mouthfuls of food in the typical American diet has a connection to bee pollination. Yet bee colonies in the United States have seen significant declines in recent years due to a combination of stressors, almost certainly including insecticide exposure. “This case underscores the need for us to re-examine how we evaluate the impact of pesticides and other chemicals in the environment,” said Mr. Colangelo. “In approving Movento, EPA identified but ignored potentially serious harms to bees and other pollinators. We are in the midst of a pollinator crisis, with more than a third of our colonies disappearing in recent years. Given how important these creatures are to our food supply, we simply cannot look past these sorts of problems.”View the court decision here.Read Beyond Pesticides’ read factsheet: Pollinators and Pesticides: Escalating crisis demands action and Backyard Beekeeping: Providing pollinator habitat one yard at a time. See more information on threats to honey bees at NRDC.

Report on Bee Mortality and Bee Surveillance in Europe

from http://www.isaaa.org/kc/cropbiotechupdate/online/default.asp?Date=12/18/2009

AFSSA, the French Food Safety Agency completed a 218-page report on honey bee mortality and the ways that colony losses are monitored in Europe, December 8, 2009. The European Food Safety Authority commissioned the study and published the report. Initially, AFSSA set up a consortium of seven European bee disease research institutes in France, Germany, Italy, Slovenia, Sweden, Switzerland, and the United Kingdom.

The project covers 1) a description and critical analysis of surveillance programs that measured colony loss; 2) the collection and analysis of the epidemiological data sets on colony losses; and 3) a critical review and selection of relevant literature on the possible causes and risk factors of colony losses.

The researchers found that bee colony losses in Europe and the USA are multifactorial which include beekeeping and husbandy practices, environmental factors, biological agents as well as excessive use of pesticides. The interaction of these factors create stress, weaken bees’ defense system allowing pests and pathogens to kill the colony.

3.2.3.3 Chemical agents

The debate on chemical agents is mainly concentrated on the agrochemicals used for crop treatments. Neonicotinoids are the focus of the greatest interest in the literature (imidacloprid, clothianidin and fipronil); other publications just mention “pesticides” in general, but certainly with an implicit consideration of neonicotinoids (Figure 75). Scientists are clearly divided on the role of these pesticides, as illustrated in Table 14. Although no involvement of pesticides has been proven for colony losses or CCD, a significant amount of pesticide residues are frequently found in the studies analysing bees, pollen and wax, usually at sublethal levels. A question arises, therefore, about the possibility for a conjunction of chemical residues present in the hive at sublethal concentrations, which may produce a lethal effect or clinical signs affecting the ability of colony to survive. Several authors mention these pesticides as factors contributing to stress or weakening of colonies which, once again, may “open the door” to other causative factors.

3.2.3.2 Biological agents

A significant number of biological agents are reported to be involved in colony losses. Viruses are the biological agents most frequently mentioned (Figure 73). As more than 15 different viruses are known to infect bees, often without any clinical symptoms and since, co-infection with several viruses is not uncommon, they are the subject of much research. Due to their frequent presence, they are found in many colony losses cases where it is very difficult to determine whether they are at the origin of the losses, or just co-factors. Of the eight viruses mentioned in the literature, IABPV is the most frequently mentioned, and some scientists consider it as a “marker” of CCD in the United States (Figure 74). Varroa, Nosema spp and Acarapis woodi infections are the three other most commonly mentioned biological factors. Some scientists consider them to be causative factors in a certain amount of colony losses (for Nosema mainly in Spain). Others consider that they are co- factors, contributing to the stress of the colony or contributing to the “expression” of colony mortality as causative factor of death for a colony already weakened by other stress factors. This is why the factors “multiple infection” and “unidentified disease” appear in the assumptions made by the authors. All these hypotheses open the floor to a debate on possible treatments to prevent or cure these infections. This links together these biological agents with chemical factors and beekeeping practices because beekeeping practices and chemical treatments are used to control infections. The debate on the involvement of the various biological agents is clearly expressed in the author’s opinions summarised in Table 13 with a high rate of “possible involvement” and balanced reports between “unlikely” and “very likely”.

3.2.4 Conclusion and perspectives

The work package on literature review allowed the development of a specific methodology for literature search and analysis. The “priority 1″ references selected and reviewed validate the objectivity of the literature search which is expressed through the variability and the balanced topics included. The results of this work regarding risk and causative factors involved in colony losses have to be taken as a “snap shot” of the scientific community’s opinion as they are today; these are also “time sensitive”, and evolving due to the amount of ongoing research which will likely lead to new findings and a better understanding of the factors involved in the coming months or years.

To summarise this picture, common consensus amongst the scientific community about the multi-factorial origin of colony losses in Europe and in the United States (in the two aspects of this term: combination of factors at one place and different factors involved according to place and period considered) suggests the following factors are important, namely: beekeeping practices (feeding, migratory beekeeping, colony husbandry, treatments applied and so forth), environmental  factors (climate, available forage, biodiversity, etc.), chemical factors (pesticides) or biological agents (Varroa, Nosema spp, etc.) which together create stress, weaken bees’ immune systems that then allow pests and pathogens to kill the colony (e.g. one or several parasites, viruses, etc.).

Figure78. Factors involved in colony losses

Questions remain about the sequence of events that lead to colony mortality, and future studies should be designed and conducted to address this:

- There are many inconsistencies in the ways in which “colony losses” are defined. Up to 17 different definitions for CCD in the literature. This means that involved persons may not always be referring to the same phenomenon, and this creates confusion when trying to explain the origin of what has been identified in the field. The described pathology is varied, with authors/using the same descriptions for different sets of circumstances. A specific study should be undertaken to clearly categorise and quantify the various expressions of colony losses in the field. This study will be closely linked to the strengthening of surveillance systems;

- High concentrations of pesticides have rarely been identified in relation to colony losses (CCD in USA and winter colony losses in Europe) although acute events of pesticide toxicity are well described during the production season (and clearly differentiated from CCD and winter colony losses). However, the questions of possible synergistic effects of various pesticides and the effect of chronic exposure to sublethal doses of pesticides remains, and requires further investigation;

- Biological agents such as parasites, viruses or bacteria, alone or in combination, have clearly been identified as important factors in colony losses. Nevertheless, there is still a lack of knowledge about the exact mechanisms and/or interactions involved, that must also be addressed;

- Even though the multifactorial origin of colony losses is well acknowledged, the respective role of each factor as a risk or causative agent is unknown, and no hierarchy of relative threat posed by each one has been established. These matters require further investigation using appropriate epidemiological studies (case control and longitudinal studies).

Conclusion

This bee surveillance project sought information on both the prevalence of honey bee colony losses, and the surveillance systems respectively in 27 European countries. Through a standardised questionnaire, each of the surveillance systems collecting these data was evaluated. In addition, a thorough literature search of the existing databases, as well as relevant grey literature about causes of colony losses was completed, and the literature evaluated.

The main conclusions from project activities can be summarised as follows:

• General weakness and high variability of most of the surveillance systems in the 25 systems investigated;
• Lack of representative data at country level and comparable data at EU level for colony losses;
• Common consensus of the scientific community about the multifactorial origin of colony losses in Europe and in the United States and insufficient knowledge of causative and risk factors for colony losses.

From these finding the consortium makes the following recommendations:

1. Implementation of a sustainable European network for coordination and follow-up of surveillance, and research on colony losses to underpin monitoring programmes;

2. Strengthen standardization at European level by harmonization of surveillance systems, data collected and by developing common performance indicators;

3. Build on the examples of best practice found in existing surveillance systems on communicable and notifiable diseases already present in some countries;

4. Undertake specific studies that build on the existing work in progress to improve the knowledge and understanding of factors that affect bee health (for example stress caused by pathogens, pesticides, environmental and technological factors and their interactions) using appropriate epidemiological studies (case control and longitudinal studies);

5. The set up of the coordination team at European level. This is a crucial issue and the coordination team should be organized in such a way so as to ensure its sustainability and to enable effective surveillance programme activities at the European level.

Complete report attached and also here: http://www.efsa.europa.eu/en/scdocs/scdoc/27e.htm

When their link breaks, download the PDF here: Scientific Report on Bee Mortality and Bee Surveillance in Europe