A pan-European epidemiological study reveals honey bee colony survival depends on beekeeper education and disease control

Reports of honey bee population decline has spurred many national efforts to understand the extent of the problem and to identify causative or associated factors. However, our collective understanding of the factors has been hampered by a lack of joined up trans-national effort. Moreover, the impacts of beekeeper knowledge and beekeeping management practices have often been overlooked, despite honey bees being a managed pollinator. Here, we established a standardised active monitoring network for 5 798 apiaries over two consecutive years to quantify honey bee colony mortality across 17 European countries. Our data demonstrate that overwinter losses ranged between 2% and 32%, and that high summer losses were likely to follow high winter losses. Multivariate Poisson regression models revealed that hobbyist beekeepers with small apiaries and little experience in beekeeping had double the winter mortality rate when compared to professional beekeepers. Furthermore, honey bees kept by professional beekeepers never showed signs of disease, unlike apiaries from hobbyist beekeepers that had symptoms of bacterial infection and heavy Varroa infestation. Our data highlight beekeeper background and apicultural practices as major drivers of honey bee colony losses. The benefits of conducting trans-national monitoring schemes and improving beekeeper training are discussed

Wildtool, a flexible, first-line risk assessment system for wildlife-borne pathogens

We describe the prototype of an electronic tool for risk assessment with dynamic ranking of wildlife-borne pathogens in function of their need for surveillance. Data about pathogens, their hosts and occurrences are obtained from literature and are classified as qualitative scores under six main criteria with their sub-criteria, corresponding to the elements of a standard risk assessment. Pathogen-specific data are reviewed by experts. The information is processed per pathogen through an algorithm and through summing up of the values obtained by converting four-tiered qualitative sub-criteria scores to weighted five-tiered numerical values. For a consistent comparison between pathogens, the "unknown" sub-criteria scores are assigned a median value of 3, allowing preservation of the sub-criteria concerned and their weights for the risk assessment, but minimizing the effect of this score on the outcome. Irregular data availability is further accommodated by a different data processing for comprehensiveness and refinement requirements, which is realised by a respective first- and second-level ranking of pathogens, the latter using additional quantitative and qualitative data for the release assessment. Continuous data updates are necessary to reflect the current situation in the field. Output flexibility is implemented by the possibility to run queries based on the choice of a region, a specific target group susceptible to the pathogens and a set of weights for the sub-criteria

Belgian honey bee winter mortality during 2012-2013 : a case-control study and spatial analysis

An increase in honey bee mortality has been reported within and outside the European Union. A Belgian honey bee health monitoring was started in 2012 based on a standardized and pan-European voluntary surveillance program (EPILOBEE). The main objective was to estimate honey bee mortality during winter and the apicultural season using a harmonized survey. For the Belgian study, the guidelines were adapted according to small-scale Belgian beekeeping practices and previous pathogen prevalence studies. A two-stage sampling stratified by province resulted in 150 apiaries selected from a sampling frame of approximately 3,000 registered beekeepers. These apiaries were visited twice, questionnaires were completed, collecting information on risk factors and mortality. Samples systematically taken in autumn were screened / quantified for Varroa destructor mites. Weighted colony winter mortality rates were estimated per individual apiary and for geographical entities. We then attempted to identify risk factors in a case-control data interpretation, with observed mortality as a binary dependent variable. Questionnaire variables were evaluated in univariable logistic regression. The final multivariable model was retained: age of beekeeper, wanting to continue beekeeping, increasing number of surrounding landscapes, average colony varroa infestation level, all associated with increased mortality. Chemical acaricide treatment before 1 September and Thymol-containing acaricide were associated with lower mortality. The predictive accuracy of this final model was estimated by the area under the curve (AUC) and was 80.70%. The final predicted mortality risk was visualized on a map as an interpolated layer and compared with the observed mortality; clusters of high/low mortality were identified. This analysis has generated further hypotheses and highlighted where the case-control study could benefit from increased sample size

Autochthonous tick-borne encephalitis virus-seropositive cattle in Belgium: a risk-based targeted serological survey

The risk of tick-borne encephalitis virus (TBEV) introduction into Belgium remains high, and the presence of infected wildlife in Belgium is suspected. Domestic animals can serve as excellent sentinels for TBEV surveillance to install an early warning surveillance component for this emerging zoonotic disease of public health importance. In a targeted, risk-based and cross-sectional sampling design, serological screening was performed on Belgian cattle (n = 650), selected from the 2010 Belgian national cattle surveillance serum bank. All samples were subjected to a gold standard TBEV seroneutralization test (SNT), based on the rapid fluorescent focus inhibition test (RFFIT) protocol. Seventeen bovines were seropositive (titer >1/15) and six had borderline results (1/10 < titer < 1/15). The accuracy of the RFFIT-SNT was confirmed in a mouse inoculation test. The overall bovine TBEV seroprevalence in the targeted area was estimated between 2.61% and 4.29%. This confirms for the first time the presence of infected foci in Belgium. Further surveillance in cattle, other sentinels, ticks, and humans at risk is recommended to further determine the location and size of endemic foci and the risk for public health

Tick-borne encephalitis virus seropositive dog detected in Belgium: screening of the canine population as sentinels for public health

Tick-borne encephalitis virus (TBEV) is an important emerging tick-borne viral infection of humans and dogs in Europe. Currently, TBEV surveillance is virtually nonexistent in Belgium, which is considered nonendemic. A commercial enzyme-linked immunosorbent assay (ELISA) was adapted for the detection of TBEV-specific IgG-antibodies in canine sera. Serum samples of Belgian dogs were obtained from three diagnostic laboratories from Northern (n = 688) and Southern Belgium (n = 192). ELISA-positive and borderline samples were subjected to a TBEV rapid fluorescent focus inhibition confirmation test. One dog was confirmed TBEV seropositive. Several ELISA-positive and borderline sera underwent seroneutralization and hemagglutinin inhibition tests to rule out West Nile and Louping Ill viruses, but tested negative. The clinical history of the seropositive dog could not explain beyond doubt where and when TBEV infection was acquired. Further surveillance is necessary to determine whether this dog remains a single travel-related case or whether it represents an early warning of a possible future emergence of TBEV

Compositional volumetry of non-calcified coronary plaques by multislice computed tomography: An ex vivo feasibility study

Aims: Non-invasive quantitative compositional analysis of coronary plaque would be a major advantage to study coronary artery disease. This study explores the application to use the Hounsfield units (HU) distribution of coronary plaques imaged by multislice computed tomography-coronary angiography (MSCT-CA). Methods and results: A dedicated computer-assisted method was developed to measure the HU distribution within a coronary plaque by MSCT-CA. To test the feasibility of the method, an ex vivo left anterior descending (LAD) coronary specimen, excised during autopsy, was imaged both by non-enhanced and enhanced MSCT-CA. Quantitative histology was used as a reference. To test the feasibility of the new volumetric analytic method, the MSCT-CA data were compared with volumetric histopathology. The coronary specimen, with a heterogeneously distributed plaque composition without large areas of calcification, was histologically sampled at five different locations, 5 mm apart, where at each location 15 sections were taken at 100 μm intervals, resulting in 75 individual histology sections. Tri-chrome Masson staining was used for histology quantification of three plaque/tissue components: smooth muscle cells (SMC), collagen and calcium. MSCT plaque composition was defined as "lower-HU" or "higher-HU" plaque and "calcium" based on the HU distribution. Comparison of the MSCT defined tissue components against histology showed a good relationship without significant differences. Conclusions: This ex vivo study shows the feasibility of using the Hounsfield unit distribution to perform compositional coronary plaque volumetry by MSCT-CA. The results are encouraging

Simultaneous targeting of IL-1 and IL-18 is required for protection against inflammatory and septic shock

Rationale: Sepsis is one of the leading causes of death around the world. The failure of clinical trials to treat sepsis demonstrates that the molecular mechanisms are multiple and are still insufficiently understood. Objectives: To clarify the long disputed hierarchical contribution of several central inflammatory mediators (IL-1 beta, IL-18, caspase [CASP] 7, CASP1, and CASP11) in septic shock and to explore their therapeutic potential. Methods: LPS- and tumor necrosis factor (TNF)-induced lethal shock, and cecal ligation and puncture (CLP) were performed in genetically or pharmacologically targeted mice. Body temperature and survival were monitored closely, and plasma was analyzed for several markers of cellular disintegration and inflammation. Measurements and Main Results: Interestingly, deficiency of both IL-1 beta and IL-18 additively prevented LPS-induced mortality. The detrimental role of IL-1 beta and IL-18 was confirmed in mice subjected to a lethal dose of TNF, or to a lethal CLP procedure. Although their upstream activator, CASP1, and its amplifier, CASP11, are considered potential therapeutic targets because of their crucial involvement in endotoxin-induced toxicity, CASP11- or CASP1/11-deficient mice were not, or hardly, protected against a lethal TNF or CLP challenge. In line with our results obtained in genetically deficient mice, only the combined neutralization of IL-1 and IL-18, using the IL-1 receptor antagonist anakinra and anti-IL-18 antibodies, conferred complete protection against endotoxin-induced lethality. Conclusions: Our data point toward the therapeutic potential of neutralizing IL-1 and IL-18 simultaneously in sepsis, rather than inhibiting the upstream inflammatory caspases