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The health of the western honeybee, Apis mellifera, the most crucial pollinator, has been challenged globally over the past decades. An ectoparasitic mite, Varroa destructor, together with the viruses it vectored, is generally regarded as the vital pathogenic agent. Although the poor health status of A. mellifera compared to its eastern counterpart, Apis cerana, has been broadly identified, the underlying mechanism remains poorly understood and comparison between susceptible and resistant hosts will potentially ameliorate this predicament. Here, we investigated the impacts of two widespread viruses—deformed wing virus type A (DWV-A) and Israeli acute paralysis virus (IAPV), mediated by V. destructor mite, on the capped developing honeybee brood, in the absence of adult workers, of A. mellifera and A. cerana, with positive and negative controls. Our results demonstrated that the endogenous viruses imposed limited damage on the hosts even if the brood was wounded. In contrast, the exogenous viruses introduced by ectoparasites triggered variable mortality of the infested brood between host species. Intriguingly, death causes of both honeybee species presented a similar trend: the acute IAPV generally causes morbidity and mortality of late larvae, while the chronic DWV-A typically leads to brood mortality during and after pupation. Notably, the susceptible immature A. cerana individuals, supported by higher observed mortality and a lower virus tolerance, serve the interests of the colony and foster the overall survival of a resistant honeybee superorganism. These results improve our understanding of the interactions between viruses carried by ectoparasites and their developing hosts, and the novel insight of weak individuals fostering strong colonies may promote breeding efforts to mitigate the indefensible colony losses globally.

Abstract Parasite host shifts can impose a high selective pressure on novel hosts. Even though the coevolved systems can reveal fundamental aspects of host–parasite interactions, research often focuses on the new host–parasite relationships. This holds true for two ectoparasitic mite species, Varroa destructor and Varroa jacobsonii, which have shifted hosts from Eastern honey bees, Apis cerana, to Western honey bees, Apis mellifera, generating colony losses of these pollinators globally. Here, we study infestation rates and reproduction of V. destructor and V. jacobsonii haplotypes in 185 A. cerana colonies of six populations in China and Thailand to investigate how coevolution shaped these features. Reproductive success was mostly similar and low, indicating constraints imposed by hosts and/or mite physiology. Infestation rates varied between mite haplotypes, suggesting distinct local co‐evolutionary scenarios. The differences in infestation rates and reproductive output between haplotypes did not correlate with the virulence of the respective host‐shifted lineages suggesting distinct selection scenarios in novel and original host. The occasional worker brood infestation was significantly lower than that of drone brood, except for the V. destructor haplotype (Korea) from which the invasive lineage derived. Whether mites infesting and reproducing in atypical intraspecific hosts (i.e., workers and queens) actually predisposes for and may govern the impact of host shifts on novel hosts should be determined by identifying the underlying mechanisms. In general, the apparent gaps in our knowledge of this coevolved system need to be further addressed to foster the adequate protection of wild and managed honey bees from these mites globally.

Abstract The ectoparasitic mite, Varroa destructor, shifted host from the eastern honeybee, Apis cerana, to the western honeybee, Apis mellifera. Whereas the original host survives infestations by this parasite, they are lethal to colonies of its new host. Here, we investigated a population of A. cerana naturally infested by the V. destructor Korea haplotype that gave rise to the globally invasive mite lineage. Our aim was to better characterize traits that allow for the survival of the original host to infestations by this particular mite haplotype. A known major trait of resistance is the lack of mite reproduction on worker brood in A. cerana. We show that this trait is neither due to a lack of host attractiveness nor of reproduction initiation by the parasite. However, successful mite reproduction was prevented by abnormal host development. Adult A. cerana workers recognized this state and removed hosts and parasites, which greatly affected the fitness of the parasite. These results confirm and complete previous observations of brood susceptibility to infestation in other honeybee host populations, provide new insights into the coevolution between hosts and parasites in this system, and may contribute to mitigating the large‐scale colony losses of A. mellifera due to V. destructor.

The poor health status of the Western honey bee, Apis mellifera, compared to its Eastern counterpart, Apis cerana, is remarkable. This has been attributed to lower pathogen prevalence in A. cerana colonies and to their ability to survive infestations with the ectoparasitic mite, Varroa destructor. These properties have been linked to an enhanced removal of dead or unhealthy immature bees by adult workers in this species. Although such hygienic behavior is known to contribute to honey bee colony health, comparative data of A. mellifera and A. cerana in performing this task are scarce. Here, we compare for the first time the removal of freeze-killed brood in one population of each species and over two seasons in China. Our results show that A. cerana was significantly faster than A. mellifera at both opening cell caps and removing freeze-killed brood. The fast detection and removal of diseased brood is likely to limit the proliferation of pathogenic agents. Given our results can be generalized to the species level, a rapid hygienic response could contribute to the better health of A. cerana. Promoting the fast detection and removal of worker brood through adapted breeding programs could further improve the social immunity of A. mellifera colonies and contribute to a better health status of the Western honey bee worldwide.

Specialization in plant-insect interactions is an important driver of evolutionary divergence; yet, plant traits mediating such interactions are poorly understood. In this study, we investigated how flower color and floral scent are related to seed predation by a seed-eating pollinator. We used field-transplanted recombinant F2 hybrids between Silene latifolia and S. dioica that are the preferred and alternative hosts of the moth Hadena bicruris and crosses within these species for comparison. We scored seed predation and flower color and analyzed floral scent. Pinker S. dioica-like flowers and emission of α-pinene decreased the odds of seed predation while emission of benzyl acetate and 6-methyl-5-hepten-2-one increased the odds of seed predation. Emission of these compounds did not differ significantly between the two Silene species. Our results suggest that flower color plays an important role in the specific interaction of H. bicruris with its preferred host S. latifolia. The compounds α-pinene, benzyl acetate and 6-methyl-5-hepten-2-one could represent non-specific deterrents and attractants to ovipositing moths. Alternatively, emission of these compounds could be related to herbivory or pathogen attack and act as a signal for host quality. This would weaken the predictability of the plant's costs and benefits of the interaction and act to maintain an imperfect degree of specialization.

Abstract Background Point-of-Care-Ultrasound (POCUS) curricula have rapidly expanded in undergraduate medical education (UME). However, the assessments used in UME remain variable without national standards. This scoping review characterizes and categorizes current assessment methods using Miller’s pyramid for skills, performance, and competence of POCUS in UME. A structured protocol was developed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR). A literature search of MEDLINE was performed from January 1, 2010, to June 15, 2021. Two independent reviewers screened all titles and abstracts for articles that met inclusion criteria. The authors included all POCUS UME publications in which POCUS-related knowledge, skills, or competence were taught and objectively assessed. Articles were excluded if there were no assessment methods used, if they exclusively used self-assessment of learned skills, were duplicate articles, or were summaries of other literature. Full text analysis and data extraction of included articles were performed by two independent reviewers. A consensus-based approach was used to categorize data and a thematic analysis was performed. Results A total of 643 articles were retrieved and 157 articles met inclusion criteria for full review. Most articles (n = 132; 84%) used technical skill assessments including objective structured clinical examinations (n = 27; 17%), and/or other technical skill-based formats including image acquisition (n = 107; 68%). Retention was assessed in n = 98 (62%) studies. One or more levels of Miller’s pyramid were included in 72 (46%) articles. A total of four articles (2.5%) assessed for students’ integration of the skill into medical decision making and daily practice. Conclusions Our findings demonstrate a lack of clinical assessment in UME POCUS that focus on integration of skills in daily clinical practice of medical students corresponding to the highest level of Miller’s Pyramid. There exists opportunities to develop and integrate assessment that evaluate higher level competencies of POCUS skills of medical students. A mixture of assessment methods that correspond to multiple levels of Miller’s pyramid should be used to best assess POCUS competence in UME.

Abstract Introduction Point-of-care ultrasonography (POCUS) is a portable imaging technology used in clinical settings. There is a need for valid tools to assess clinical competency in POCUS in medical students. The primary aim of this study was to use Kane’s framework to evaluate an interpretation-use argument (IUA) for an undergraduate POCUS assessment tool. Methods Participants from Memorial University of Newfoundland, the University of Calgary, and the University of Ottawa were recruited between 2014 and 2018. A total of 86 participants and seven expert raters were recruited. The participants performed abdominal, sub-xiphoid cardiac, and aorta POCUS scans on a volunteer patient after watching an instruction video. The participant-generated POCUS images were assessed by the raters using a checklist and a global rating scale. Kane’s framework was used to determine validity evidence for the scoring inference. Fleiss’ kappa was used to measure agreement between seven raters on five questions that reflected clinical competence. The descriptive comments collected from the raters were systematically coded and analyzed. Results The overall agreement between the seven raters on five questions on clinical competency ranged from fair to moderate (κ = 0.32 to 0.55). The themes from the qualitative data were poor image generation and interpretation (22%), items not applicable (20%), poor audio and video quality (20%), poor probe handling (10%), and participant did not verbalize findings (14%). Conclusion The POCUS assessment tool requires further modification and testing prior before it can be used for reliable undergraduate POCUS assessment.

The thinking about metallic replacement has begun in a global context of reducing metallic alloys’ use in odontology. Among the materials proposed for their replacement, poly(etheretherketone) may present interesting properties, especially in removable dentures’ frames. The purpose of this study is to evaluate fracture resistance of PEEK posts-and-cores compared to non-metallic CAD/CAM materials and fiber glass posts. Forty extracted maxillary central incisors were prepared to receive posts. Samples were divided into four groups depending on whether they had been reconstructed with LuxaCam® PEEK, Enamic®, Numerys GF® or LuxaPost®. Samples were submitted to an oblique compressive test and results were statistically analyzed with ANOVA and Student’s tests (or non-parametric tests depending on the conditions). Glass fiber posts and Numerys GF® reveal a significantly higher fracture resistance than LuxaCam® PEEK and Enamic®. No exclusively dental fracture has been noted for the Enamic group, which significantly distinguishes these samples from the three other groups. In our study, it appears that the conception of posts and cores with hybrid ceramic never conducts to a unique tooth fracture. By weighting the results according to the materials used, our data, obtained for the first time on this type of PEEK block, cannot confirm the possibility of using PEEK for inlay-core conception, excepted for specific cases when the material is considered in a patient presenting allergies or systemic disease contraindicating resin or metal.

Background and objective Despite firearms contributing to significant morbidity and mortality globally, firearm injury epidemiology is seldom described outside of the USA. We examined firearm injuries among youth in Canada, including weapon type, and intent.Design Population-based, pooled cross-sectional study using linked health administrative and demographic databases.Setting Ontario, Canada.Participants All children and youth from birth to 24 years, residing in Ontario from 1 April 2003 to 31 March 2018.Exposure Firearm injury intent and weapon type using the International Classification of Disease-10 CM codes with Canadian enhancements. Secondary exposures were sociodemographics including age, sex, rurality and income.Main outcomes Any hospital or death record of a firearm injury with counts and rates of firearm injuries described overall and stratified by weapon type and injury intent. Multivariable Poisson regression stratified by injury intent was used to calculate rate ratios of firearm injuries by weapon type.Results Of 5486 children and youth with a firearm injury (annual rate: 8.8/100 000 population), 90.7% survived. Most injuries occurred in males (90.1%, 15.5/100 000 population). 62.3% (3416) of injuries were unintentional (5.5/100 000 population) of which 1.9% were deaths, whereas 26.5% (1452) were assault related (2.3/100 00 population) of which 18.7% were deaths. Self-injury accounted for 3.7% (204) of cases of which 72.0% were deaths. Across all intents, adjusted regression models showed males were at an increased risk of injury. Non-powdered firearms accounted for half (48.6%, 3.9/100 000 population) of all injuries. Compared with handguns, non-powdered firearms had a higher risk of causing unintentional injuries (adjusted rate ratio (aRR) 14.75, 95% CI 12.01 to 18.12) but not assault (aRR 0.84, 95% CI 0.70 to 1.00).Conclusions Firearm injuries are a preventable public health problem among youth in Ontario, Canada. Unintentional injuries and those caused by non-powdered firearms were most common and assault and self-injury contributed to substantial firearm-related deaths and should be a focus of prevention efforts.

Background: The expectations of point-of-care ultrasound (PoCUS) in undergraduate clerkship at the University of Ottawa has not been described. We compared clerkship directors’ expectations of physical examination skills with PoCUS skills, before and after completing the clerkship rotation. Methods: A pilot-tested, expert developed, bilingual on-line survey consisting of 15 questions was sent to all clerkship directors (23) in December 2019. The survey included questions regarding the expectations of medical students with respect to physical examination and PoCUS using the RIME Framework: none, reporter, interpreter, manager, educator. Results: The response rate was 60.9% (14/23). With regards to physical exam skills, 82.8% of directors had no expectations or expected students to be reporters when starting clerkship. At graduation, 77.5% of directors expected students to be interpreters, managers, or educators. For PoCUS, 100.0% of directors had no expectations or expected students to be reporters when starting clerkship. At clerkship completion, 33.0% of directors felt that students should be interpreters or managers for PoCUS skills. Conclusions: Clerkship directors have low expectations of PoCUS skills for entering and graduating clerks when compared with their physical examination skills despite formal pre-clerkship PoCUS objectives. Enhanced communication and targeted education of directors could improve the PoCUS curriculum.

This study explores the use of mesenchymal stem cells (MSCs) for intervertebral disc regeneration. We used an in vivo model to investigate the feasibility of exogenous cell delivery, retention, and survival in the pressurized disc space. MSC injection into rat coccygeal discs was performed using 15% hyaluronan gel as a carrier. Injections of gel with or without MSCs were performed. Immediately after injection, fluorescently labeled stem cells were visible on sections of cell-injected discs. Seven and 14 days after injection, stem cells were still present within the disc, but their numbers were significantly decreased. At 28 days, a return to the initial number of injected cells was observed, and viability was 100%. A trend of increased disc height compared to blank gel suggests an increase in matrix synthesis. The results indicate that MSCs can maintain viability and proliferate within the rat intervertebral disc. [ABSTRACT FROM AUTHOR]