Phylogeny, morphology, virulence, ecology, and host range of Ordospora pajunii (Ordosporidae), a microsporidian symbiont of Daphnia spp.

The impacts of microsporidia on host individuals are frequently subtle and can be context dependent. A key example of the latter comes from a recently discovered microsporidian symbiont of Daphnia, the net impact of which was found to shift from negative to positive based on environmental context. Given this, we hypothesized low baseline virulence of the microsporidian; here, we investigated the impact of infection on hosts in controlled conditions and the absence of other stressors. We also investigated its phylogenetic position, ecology, and host range. The genetic data indicate that the symbiont is Ordospora pajunii, a newly described microsporidian parasite of Daphnia. We show that O. pajunii infection damages the gut, causing infected epithelial cells to lose microvilli and then rupture. The prevalence of this microsporidian could be high (up to 100% in the lab and 77% of adults in the field). Its overall virulence was low in most cases, but some genotypes suffered reduced survival and/or reproduction. Susceptibility and virulence were strongly host-genotype dependent. We found that North American O. pajunii were able to infect multiple Daphnia species, including the European species Daphnia longispina, as well as Ceriodaphnia spp. Given the low, often undetectable virulence of this microsporidian and potentially far-reaching consequences of infections for the host when interacting with other pathogens or food, this Daphnia-O. pajunii symbiosis emerges as a valuable system for studying the mechanisms of context-dependent shifts between mutualism and parasitism, as well as for understanding how symbionts might alter host interactions with resources. IMPORTANCE: The net outcome of symbiosis depends on the costs and benefits to each partner. Those can be context dependent, driving the potential for an interaction to change between parasitism and mutualism. Understanding the baseline fitness impact in an interaction can help us understand those shifts; for an organism that is generally parasitic, it should be easier for it to become a mutualist if its baseline virulence is relatively low. Recently, a microsporidian was found to become beneficial to its Daphnia hosts in certain ecological contexts, but little was known about the symbiont (including its species identity). Here, we identify it as the microsporidium Ordospora pajunii. Despite the parasitic nature of microsporidia, we found O. pajunii to be, at most, mildly virulent; this helps explain why it can shift toward mutualism in certain ecological contexts and helps establish O. pajunii is a valuable model for investigating shifts along the mutualism-parasitism continuum.

How does parasite environmental transmission stage concentration change before, during, and after disease outbreaks?

Outbreaks of environmentally transmitted parasites require that susceptible hosts encounter transmission stages in the environment and become infected, but we also know that transmission stages can be in the environment without triggering disease outbreaks. One challenge in understanding the relationship between environmental transmission stages and disease outbreaks is that the distribution and abundance of transmission stages outside of their hosts have been difficult to quantify. Thus, we have limited data about how changes in transmission stage abundance influence disease dynamics; moreover, we do not know whether the relationship between transmission stages and outbreaks differs among parasite species. We used digital PCR to quantify the environmental transmission stages of five parasites in six lakes in southeastern Michigan every 2 weeks from June to November 2021. At the same time, we quantified infection prevalence in hosts and host density. Our study focused on eight zooplankton host species (Daphnia spp. and Ceriodaphnia dubia) and five of their parasites from diverse taxonomic groups (bacteria, yeast, microsporidia, and oomycete) with different infection mechanisms. We found that parasite transmission stage concentration increased prior to disease outbreaks for all parasites. However, parasites differed significantly in the relative timing of peaks in transmission stage concentration and infection outbreaks. The "continuous shedder" parasites had transmission stage peaks at the same time as or slightly after the outbreak peaks. In contrast, parasites relying on host death for transmission ("obligate killers") had transmission stage peaks before outbreak peaks. For most parasites, lakes with outbreaks had higher spore concentrations than those without outbreaks, especially once an outbreak began; the exception was for a parasite, Pasteuria ramosa, with very strong genotypic specificity of infection. Overall, our results show that disease outbreaks are tightly linked to transmission stage concentration; outbreaks were preceded by increases in transmission stage concentration in the environment and then were fueled by the production of more transmission stages during the outbreak itself, with concentrations decreasing to pre-outbreak levels as outbreaks waned. Thus, tracking transmission stages in the environment improves our understanding of the drivers of disease outbreaks and reveals how parasite traits may affect these dynamics.

Fitness effects of spontaneous mutations in a warming world.

Spontaneous mutations fuel evolutionary processes and differ in consequence, but the consequences depend on the environment. Biophysical considerations of protein thermostability predict that warm temperatures may systematically increase the deleteriousness of mutation. We sought to test whether mutation reduced fitness more when measured in an environment that reflected climate change projections for temperature. We investigated the effects of spontaneous mutations on life history, size, and fitness in 21 mutation accumulation lines and 12 control lines of Daphnia pulex at standard and elevated (+4℃) temperatures. Warmer temperature accelerated life history and reduced body length and clutch sizes. Mutation led to reduced mean clutch sizes and fitness estimates at both temperatures. We found no evidence of a systematic temperature-mutation interaction on trait means, although some lines showed evidence of beneficial mutation at one temperature and deleterious mutation at the other. However, trait variances are also influenced by mutation, and we observed increased variances due to mutation for most traits. For variance of the intrinsic rate of increase and some reproductive traits, we found significant temperature-mutation interactions, with a larger increase due to mutation in the warmer environment. This suggests that selection on new mutations will be more efficient at elevated temperatures.

Impact of Demographic Factors, Obesity, and Oral Health Status on Self-esteem among School-going Children in United Arab Emirates: A Cross-sectional Study.

OBJECTIVES: The objective of this study was to determine if oral health, obesity, and demographic factors have an impact on self-esteem among school-going children in United Arab Emirates. MATERIALS AND METHODS: Ten schools (six private and four public) were selected using random digit table. Decayed, missing, and filled teeth index according to the World Health Organization criteria was used to assess dental caries. Obesity was measured by body mass index (BMI = weight [kg]/height [m2]). Data related to demographic details and toothbrushing were collected and entered into assessment forms. The mental well-being was assessed using Rosenberg Self-esteem Scale. RESULTS: Self-esteem score was 19.8 (standard deviation [SD], ±3.8) mean, and ranged from 19.1 to 20.5. The presence or absence of dental caries or their body shape (obesity/overweight/normal weight) had no impact on the self-esteem scores. Of the participants, 93% brushed daily, whereas the brushing frequency was significantly greater in female children (98%) (P < 0.001) and children with higher self-esteem scores (P = 0.066). The self-esteem scores of school children was positively associated with age as elder children had higher scores (P = 0.001). Children of Indian origin had lower self-esteem (P = 0.004). BMI was negatively associated (P = 0.006). CONCLUSION: Rosenberg Self-esteem Scale scores were found to be lower in young children and Indian children. The child's obesity and dental caries status had no significant influence on their self-esteem. High self-esteem in older children can be linked with increased toothbrushing frequency.

Indiana community pharmacist preceptors' knowledge and perceptions of medication-assisted treatment.

OBJECTIVES: The study aim was to characterize the Indiana community-based pharmacist preceptors' knowledge and perceptions of medication-assisted treatment (MAT) for opioid use disorder (OUD). The secondary objectives were to explore the desired resources, dispensing concerns, and preceptors' involvement in precepting students. DESIGN: A 38-item survey was used to collect respondent demographics, knowledge, and perceptions of MAT for OUD. Perception questions were developed using the social cognitive theory and were adapted from previously published surveys with investigators' permission. SETTING: Community-based Indiana pharmacist preceptors were eligible to complete an electronic survey in February and March 2019. OUTCOME MEASURES: Descriptive statistics were used to characterize preceptor knowledge and perceptions of MAT for OUD. Desired MAT resources, dispensing concerns, and level of involvement in precepting students were collected. Respondent demographics were collected to characterize the study sample. RESULTS: Of the 116 survey responses, 104 were eligible, and 79 community-based pharmacist preceptors completed the survey, yielding a response rate of 76.0%. For knowledge questions, the overall correct score was 56.2%. Respondents had high correct scores on questions related to medication access. However, respondents either self-identified or performed poorly on the following knowledge items: Food and Drug Administration-approved MAT products for OUD, the need to provide an opioid-free interval before initiating treatment with buprenorphine and naltrexone, pregnancy recommendations, and treatment of severe OUD. Respondents reported positive perceptions on MAT for OUD, but identified concerns regarding diversion and misuse of MAT. Most respondents reported a desire for additional education on different aspects of MAT for OUD. Dispensing concerns and preceptors' involvement with students in MAT ranged from no concern and lack of involvement to many different concerns and full student involvement. CONCLUSION: Opportunities exist to fill identified gaps in knowledge, enhance perceptions, and provide desired continuing education for community-based pharmacist preceptors on MAT for OUD.

Evaluating the risk factors that link obesity and dental caries in 11-17-year-old school going children in the United Arab Emirates.

OBJECTIVE: The objective is to study the effect of obesity on dental caries among schoolchildren in Sharjah, United Arab Emirates. MATERIALS AND METHODS: The sample comprised 803, 11-17-year-old schoolchildren. The study was in the form of a randomized cross-sectional manner. Method used was two questioners. The first assessed socioeconomic and general health and the second detailed their demographic, oral hygiene, and dietary habits. Dental examination included dental caries assessment using the World Health Organization 1997 criteria and gingival health valuation. Clinical examination consisted of height, weight, and body mass index (BMI). Data analysis was done by descriptive, univariate, and multiple regressions. RESULTS: In this sample, 75% had dental caries and the mean decayed, missing, and filled teeth (DMFT) was 3.19 (standard deviation: 2.9). Obesity was seen in 15% of the adolescents and the mean BMI was 21. The link between DMFT and BMI, when evaluated using univariate analysis, showed a significant correlation (r = 0.097, P = 0.006), indicating that the rise in BMI by 10 points resulted in an increase in DMFT by 0.57. However, in the multivariate analysis, a significant relationship was observed only between father's education (P < 0.001), adolescent's age (P < 0.001), gender (P = 0.008), ethnicity (P = 0.001), and soft drink consumption with DMFT while BMI showed a significant association with age (P < 0.001), school fees (P = 0.005), obesity in family (P < 0.001), and soft drink consumption (P < 0.001). CONCLUSIONS: Obesity and dental caries were not significantly associated. The most important predictor for obesity and dental caries was soft drink consumption.

Summary of: Interactions in the dental team: understanding theoretical complexities and practical challenges.

BACKGROUND: Interdisciplinary collaboration and communication during dental training has become an increasingly influential idea within dental schools, both in the United Kingdom and European contexts. Research into this curriculum innovation has provided evidence to argue that benefits accrue both in terms of professional understanding and the development of dental professional learning dispositions. OBJECTIVE: This study investigates the interactions within a trainee dental team. In particular, the paper reports the professional experiences and development of trainee dental technicians and undergraduate dental students during a prolonged shared learning exercise in a combined UK university dental school and hospital. METHODS: Using a qualitative approach with a phenomenological framework, data sources included reflective diaries, focus group interviews and participant feedback. RESULTS: Eleven major domains were identified that accurately characterised the participants' beliefs, thoughts and practices. The results indicate that both trainee dental technicians and undergraduate dental students were pragmatic but positive in terms of their expectations of shared learning. In particular, they regarded the exercise as useful in terms of communication and understanding each other's role. Evidence also indicated the presence of original elements such as crisis of confidence and feelings of awkwardness that do not arise in other studies. CONCLUSIONS: The implications for dental education are that for effective professional collaboration during training to take place a merger of interests among educators and policy developers in dental education must occur, and the challenges encountered within practice cultures must somehow be overcome. Therefore, more investment in evaluating research into interprofessional learning in dentistry would contribute to our knowledge about the place and role of interprofessional education in the professional dental curriculum and beyond.

Dental therapists: a global perspective.

In 1921, New Zealand began training school dental nurses, subsequently deploying them throughout the country in school-based clinics providing basic dental care for children. The concept of training dental nurses, later to be designated dental therapists, was adopted by other countries as a means of improving access to care, particularly for children. This paper profiles six countries that utilise dental therapists, with a description of the training that therapists receive in these countries, and the context in which they practice. Based on available demographic information, it also updates the number of dental therapists practising globally, as well as the countries in which they practice. In several countries, dental therapy is now being integrated with dental hygiene in training and practice to create a new type of professional complementary to a dentist. Increasingly, dental therapists are permitted to treat adults as well as children. The paper also describes the status of a current initiative to introduce dental therapy to the United States. It concludes by suggesting that dental therapists can become valued members of the dental team throughout the world, helping to improve access to care and reducing existing disparities in oral health.

Appraising and assessing reflection in students' writing on a structured worksheet.

BACKGROUND: A variety of teaching and learning techniques intended to engage students in reflection are either in use or are being developed in medical and dental education. In line with evidence-based practice in education, research is needed to appraise the utility and effectiveness of these techniques, so that they may be used with confidence. AIM: To assess whether students completing a 'reflective' learning activity based on a structured worksheet really were reflecting. METHOD: A qualitative, multi-method approach was taken. Worksheets completed by students were examined for evidence of reflection by researchers using two sets of criteria for the assessment of reflection derived from the literature, and by peer judges using their own criteria. The opinions of students completing the activity, regarding its acceptability and utility, were elicited by a questionnaire incorporating a 5-point Likert scale. RESULTS: Results from all methods suggest that students completing the activity were reflecting. Students' opinions of the activity were mainly positive. CONCLUSION: The methods employed may be of use to educators wishing to appraise reflective learning activities or, possibly, to assess student reflection.

Possible association between amniotic fluid micro-organism infection and microflora in the mouth.

OBJECTIVE: To determine whether oral bacteria are found in the amniotic cavity. DESIGN: Laboratory based analysis of clinical samples. SETTING: Royal London Hospital, Whitechapel. POPULATION: Forty-eight women attending for elective caesarean section. METHODS: Dental plaque, a high vaginal swab, amniotic fluid and chorioamnion tissue were taken from women with intact membranes. MAIN OUTCOME MEASURES: Samples were investigated using culture and microscopy for the presence of microorganisms. Amniotic fluid was analysed by polymerase chain reaction (PCR) for the presence of the ubiquitous 16S rRNA gene specific to most eubacteria. Samples were analysed using PCR genus and species specific primers directed to bacterial taxa found as part of the normal oral microflora (Streptococcus spp. and Fusobacterium nucleatum). Levels of prostaglandin E2 and cytokines were measured in amniotic fluid. RESULTS: Amniotic fluid was positive for universal bacteria PCR, Streptococcus spp. PCR and F. nucleatum PCR in 34/48, 20/48 and 7/48 of cases, respectively. Streptococcus spp. and F. nucleatum were cultured from the dental plaque, vagina and amniotic fluid of 48/48, 14/48, 0/48 and 29/48, 6/48, 0/48 subjects, respectively. A significant association was found between detection of microbial DNA (universal and F. nucletum) and complications in previous pregnancies including miscarriage, intrauterine death, neonatal death, preterm delivery and premature rupture of membranes (P < 0.05 and P < 0.01, respectively). Prostaglandin E2 and cytokine levels, with the exception of IL-1alpha, were not significantly different between women with and without evidence of infection. CONCLUSIONS: The results indicate that Streptococcus spp. and F. nucleatum in the amniotic fluid may have an oral origin.

Practice-based learning: emerging professional characteristics, self-concepts and patterns of knowing in dental training.

This paper reports on a content analysis of a reflective learning activity named "A Learning Experience". The study aimed to elucidate the reflections of dental undergraduates and dental therapy students with the purpose of analysing the meaning they attribute to their experiences in training. Thirty-one student-completed worksheets were analysed by drawing themes and patterns from the text. In addition, responses were categorised according to patterns of knowing: empirical, aesthetic, personal and ethical. Findings show that students focused mainly on negative experiences and problem situations. Student reflections showed all 4 patterns of knowing and highlighted emerging professional characteristics and students' own professional self-concepts. Findings are discussed in the light of a growing trend in higher and professional education to encourage reflection on learning and practice.