Over the last few years, many European and North American countries have reported a high rate of disorders (mortality, dwindling and disappearance) affecting honeybee colonies (Apis mellifera). ...Although beekeeping has become an increasingly professional activity in recent years, the beekeeping industry remains poorly documented in Europe. The European Union Reference Laboratory for Honeybee Health sent a detailed questionnaire to each Member State, in addition to Kosovo and Norway, to determine the demographics and state of their beekeeping industries. Based on data supplied by the National Reference Laboratory for honeybee diseases in each European country, a European database was created to describe the beekeeping industry including the number and types of beekeepers, operation size, industry production, and health (notifiable diseases, mortalities). The total number of beekeepers in Europe was estimated at 620,000. European honey production was evaluated at around 220,000 tons in 2010. The price of honey varied from 1.5 to 40 €/kg depending on the country and on the distribution network. The estimated colony winter mortality varied from 7 to 28% depending on the country and the origin of the data (institutional survey or beekeeping associations). This survey documents the high heterogeneity of the apicultural industry within the European Union. The high proportion of non-professional beekeepers and the small mean number of colonies per beekeeper were the only common characteristics at European level. The tremendous variation in European apicultural industries has implication for any comprehensive epidemiological or economic analysis of the industry. This variability needs to be taken into account for such analysis as well as for future policy development. The industry would be served if beekeeping registration was uniformly implemented across member states. Better information on the package bee and queen production would help in understanding the ability of the industry to replace lost honey bee stocks.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Co-exposure to pesticides and viruses is likely to occur in honey bee colonies. Pesticides can be present in pollen, nectar, and persist in stored food (honey and bee bread), and viruses can be ...highly prevalent in honey bee colonies. Therefore, the present study describes the influence of chronic co-exposure to thiamethoxam and Chronic bee paralysis virus (CBPV) on bee survival, virus loads, expression level of immune and detoxication genes, and pesticide metabolism Experiments were performed on honey bees collected from a winter apiary with reduced viral contaminations. No synergistic effect of co-exposure was observed on bee survival, nor on the ability of bees to metabolise the pesticide into clothianidin. However, we found that co-exposure caused an increase in CBPV loads that reached the viral levels usually found in overt infections. The effect of co-exposure on CBPV replication was associated with down-regulation of vitellogenin and dorsal-1a gene transcription. Nevertheless, the observed effects might be different to those occurring in spring or summer bees, which are more likelyco-exposed to thiamethoxam and CBPV and exhibit a different physiology.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Exposure to multiple stress factors is believed to contribute to honey bee colony decline. However, little is known about how co-exposure to stress factors can alter the survival and behavior of ...free-living honey bees in colony conditions. We therefore studied the potential interaction between a neonicotinoid pesticide, thiamethoxam, and a highly prevalent honey bee pathogen,
(DWV). For this purpose, tagged bees were exposed to DWV by feeding or injection, and/or to field-relevant doses of thiamethoxam, then left in colonies equipped with optical bee counters to monitor flight activity. DWV loads and the expression of immune genes were quantified. A reduction in vitellogenin expression level was observed in DWV-injected bees and was associated with precocious onset of foraging. Combined exposure to DWV and thiamethoxam did not result in higher DWV loads compared to bees only exposed to DWV, but induced precocious foraging, increased the risk of not returning to the hive after the first flight, and decreased survival when compared to single stress exposures. We therefore provided the first evidence for deleterious interactions between DWV and thiamethoxam in natural conditions.
•The accuracy of 5 RT-qPCRs was assessed for their ability to quantify Europe’s most frequently-detected viruses.•Honeybees collected in France (2012–2019) were tested to determine the frequency of ...each viral load.•Viral load thresholds were suggested to differentiate covert from overt infections.
Acute bee paralysis virus (ABPV), Black queen cell virus (BQCV), Chronic bee paralysis virus (CBPV), Deformed wing virus (DWV), Sacbrood virus (SBV) and Varroa destructor virus 1 (VDV1) are the six main honeybee viruses reported in Europe. We assessed the accuracy (trueness and precision) of reverse transcriptase quantitative TaqMan® PCR methods (RT-qPCR) for quantifying ABPV, BQCV, DWV, VDV1 and SBV loads. Once the systematic bias in quantitative results had been corrected (overestimation in ABPV and BQCV quantification and underestimation in that of SBV and VDV1), measurements were taken to determine the viral load ranges for which quantification uncertainty was below ± 1 log10 equivalent of genome copies per bee (hereafter reported as genome copies/bee). The accuracy range of RT-qPCR was found to be between 6.4 and 10.4 log10 genome copies/bee for ABPV, between 3.0 and 10.0 log10 genome copies/bee for BQCV, between 2.4 and 10.4 log10 genome copies/bee for DWV and between 3.4 and 10.4 log10 genome copies/bee for SBV. Outside these ranges, the results’ uncertainty is higher. VDV1 RT-qPCR accuracy was outside accuracy limits for all viral loads. Using these RT-qPCR methods, we quantified viral loads in naturally-infected honeybees. The viral load distribution and clinical signs reported with the honeybee samples allowed us to define a threshold that could be used to differentiate between covert and overt infections. These methods will be useful in diagnosing the main viral infections impairing honeybee health.
Pollen traps are used by beekeepers to collect pollen harvested by honeybees. Here, we set up an experiment to evaluate whether pollen traps are a risk factor involved in the development of the ...chronic bee paralysis, a viral honeybee disease affecting adult bees and transmitted by contact. After a recent episode of chronic bee paralysis in an apiary, pollen traps were installed on three hives while two hives without pollen traps were used as control. During the experiment, the chronic bee paralysis virus (CBPV) loads in foragers from the control hives remained lower than 10
8
equivalent copies of CBPV genome per bee but were higher than 10
10
equivalent copies of CBPV genome per bee in the many symptomatic bees and in the hundreds of dead bees found in front of trap hives. Clinical signs of the disease persisted for 3 weeks at the entrance of the trap hives. These signs disappeared after the pollen traps were removed, accompanied by a decrease in the viral loads in foragers. Despite the small number of colonies examined, the results of this study suggest the impact of pollen traps on the relapse of chronic paralysis outbreaks in colonies infected by CBPV.
Aethina tumida
(small hive beetle, SHB) was first detected in September 2014 in Calabria region, southern Italy, and in a single apiary in Sicily in November 2014. In September 2015, SHB was again ...recorded in Calabria, and in 2016, only sentinel honey bee nucleus colonies were found to be infested. Its phylogenetic relationship and possible origin were investigated comparing the
cox1
sequences with the corresponding region available in the GenBank database. The neighbour-joining method revealed that the first Italian specimen belonged to a group also containing an African specimen from Cameroon. The Italian specimens differ from the SHBs spread worldwide and are split into two different groups: group B1 includes the AfricCam3 sequence and the first SHB identified in Calabria; group B2 includes specimens from Calabria and the only one from Sicily which share identical
cox1
sequences. SHB in Italy appears to have been introduced from Africa and includes independent or contemporary incursions in the two concerned regions. The most likely scenario is that SHB was introduced into Calabria followed by man-mediated migration to Sicily.
Chronic bee paralysis virus (CBPV) is the etiological agent of chronic paralysis, an infectious and contagious disease in adult honeybees. CBPV is a positive single-stranded RNA virus which contains ...two major viral RNA fragments. RNA 1 (3674 nt) and RNA 2 (2305 nt) encode three and four putative open reading frames (ORFs), respectively. RNA 1 is thought to encode the viral RNA-dependent RNA polymerase (RdRp) since the amino acid sequence derived from ORF 3 shares similarities with the RdRP of families Nodaviridae and Tombusviridae. The genomic organization of CBPV and in silico analyses have suggested that RNA 1 encodes non-structural proteins, while RNA 2 encodes structural proteins, which are probably encoded by ORFs 2 and 3. In this study, purified CBPV particles were used to characterize virion proteins by mass spectrometry. Several polypeptides corresponding to proteins encoded by ORF 2 and 3 on RNA 2 were detected. Their role in the formation of the viral capsid is discussed.
We report here the full mitochondrial genome sequence of
, a Nitidulidae species beetle, that is a pest of bee hives. The obtained sequence is 16,576 bp in length and contains 13 protein-coding ...genes, 2 rRNA genes, and 22 tRNAs.
Chronic bee paralysis virus (CBPV) causes an infectious and contagious disease of adult honeybees. Its segmented genome is composed of two major positive single-stranded RNAs, RNA 1 (3,674 nt) and ...RNA 2 (2,305 nt). Three minor RNAs (about 1,000 nt each) have been described earlier but they were not detected by sequencing of CBPV genome. In this study, the results of in vivo inoculation of the two purified CBPV major RNAs are presented and demonstrate that RNA 1 and RNA 2 are infectious. Honeybees inoculated with 109 RNA copies per bee developed paralysis symptoms within 6 days after inoculation. The number of CBPV RNA copies increased significantly throughout the infection. Moreover, the negative strand of CBPV RNA was detected by RT-PCR, and CBPV particles were visualized by electronic microscopy in inoculated honeybees. Taken together, these results show that CBPV RNA 1 and CBPV RNA 2 segments can induce virus replication and produce CBPV virus particles. Therefore, the three minor RNAs described in early studies are not essential for virus replication. These data are crucial for the development of a reverse genetic system for CBPV.
The first detection of Aethina tumida Murray (the small hive beetle) in Italy occurred on 5 September 2014. Three nuclei containing honey bees (Apis mellifera) and located in a clementine (citrus) ...orchard near an important international harbour in the Calabria region (southern Italy) were heavily infested with adult and larval A. tumida. A. tumida infestation is a notifiable disease of honey bees in the European Union as well as an OIE listed disease. To prevent any A. tumida introduction, the importation of honey bees is regulated strictly in the European Union (Commission Regulation (EU) No. 206/2010). Early reaction measures adopted in Italy require that beekeepers must notify A. tumida discovery to the local veterinary services and cannot move their colonies. Furthermore, a protection area (20 km radius) and surveillance (100 km radius) zone should be established. The surveillance zone now includes the entire territory of Calabria region. Compulsory visits to all apiaries in the protection zone with the collection of the spatial information by means of a georeferentiation process (georeferentiation can be defined as the process to describe a location relative to the earth, in this context the process consists on the collection of the spatial coordinate of a point that represents the spatial location of the apiaries by means of a GPS device) and colony inspection according to 5% expected prevalence (95% CI) are applied. Destruction of infested apiaries is compulsory and the soil under the infested colonies must be ploughed and treated with pyrethroids. If apiaries in the protection zone are found to be negative, traps are placed. In the surveillance zone, veterinarians visit apiaries that are selected according to a risk analysis (migration in infested areas, honey bee or materials exchange) or randomly and colonies are inspected according to 2% expected prevalence (95% CI). Furthermore, in Italy as well in the rest of Europe, investigations are in progress by competent authorities to make an inventory of all bees and colonies moved from Calabria during 2014. Subsequent controls on colonies should be implemented. People from the honey bee network (beekeepers, veterinarians, beekeeping material producers and distributors) should be aware and informed of the hazard posed by A. tumida to honey bees.
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