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Abstract Background Since 1999, field evidence of transplacental infection by porcine circovirus type 2 (PCV2) and reproductive failure has been reported in pigs. The objective of this study was to evaluate the clinical and pathological consequences of PCV2 infection in conventional PCV2-seropositive gilts by insemination with PCV2b-spiked semen. Results Six PCV2 seropositive gilts were inseminated with PCV2b-supplemented semen (infected) and three animals with semen and cell culture medium (controls). Only three out of the six infected animals were pregnant by ultrasonography on day 29 after insemination, while two out of the three controls were pregnant. One control gilt aborted on day 23 after insemination but not due to PVC2. Viraemia was demonstrated in four out of six infected and in one control gilt that became infected with PCV2a. Anti-PCV2 antibody titres showed dynamic variations in the infected group throughout the study. Among infected gilts, the animal with the lowest anti-PCV2 titre (1/100) at the beginning of the experiment and another that reached a similar low value during the experiment showed evident seroconversion over time and had also PCV2 positive foetuses. One placenta displayed mild focal necrosis of the chorionic epithelium positively stained by immunohistochemistry for PCV2 antigen. Conclusions PCV2-seropositive gilts can be infected with PCV2 after intrauterine exposure and low maternal antibody titre may increase the probability of a foetal infection.

Abstract Background Diagnosis of West Nile virus (WNV) infections is often difficult due to the extensive antigenic cross-reactivity among flaviviruses, especially in geographic regions where two or more of these viruses are present causing sequential infections. The purpose of this study was to characterize a panel of monoclonal antibodies (MAbs) produced against WNV to verify their applicability in WNV diagnosis and in mapping epitope targets of neutralizing MAbs. Methods Six MAbs were produced and characterized by isotyping, virus-neutralization, western blotting and MAb-epitope competition. The MAb reactivity against various WNVs belonging to lineage 1 and 2 and other related flaviviruses was also evaluated. The molecular basis of epitopes recognized by neutralizing MAbs was defined through the selection and sequencing of MAb escape mutants. Competitive binding assays between MAbs and experimental equine and chicken sera were designed to identify specific MAb reaction to epitopes with high immunogenicity. Results All MAbs showed stronger reactivity with all WNVs tested and good competition for antigen binding in ELISA tests with WNV-positive equine and chicken sera. Four MAbs (3B2, 3D6, 4D3, 1C3) resulted specific for WNV, while two MAbs (2A8, 4G9) showed cross-reaction with Usutu virus. Three MAbs (3B2, 3D6, 4D3) showed neutralizing activity. Sequence analysis of 3B2 and 3D6 escape mutants showed an amino acid change at E307 (Lys → Glu) in the E protein gene, whereas 4D3 variants identified mutations encoding amino acid changed at E276 (Ser → Ile) or E278 (Thr → Ile). 3B2 and 3D6 mapped to a region on the lateral surface of domain III of E protein, which is known to be a specific and strong neutralizing epitope for WNV, while MAb 4D3 recognized a novel specific neutralizing epitope on domain II of E protein that has not previously been described with WNV MAbs. Conclusions MAbs generated in this study can be applied to various analytical methods for virological and serological WNV diagnosis. A novel WNV-specific and neutralizing MAb (4D3) directed against the unknown epitope on domain II of E protein can be useful to better understand the role of E protein epitopes involved in the mechanism of WNV neutralization.

Abstract A fatal Encephalomyocarditis virus (EMCV) infection epidemic involving fifteen primates occurred between October 2006 and February 2007 at the Natura Viva Zoo. This large open-field zoo park located near Lake Garda in Northern Italy hosts one thousand animals belonging to one hundred and fifty different species, including various lemur species. This lemur collection is the most relevant and rich in Italy. A second outbreak between September and November 2008 involved three lemurs. In all cases, the clinical signs were sudden deaths generally without any evident symptoms or only with mild unspecific clinical signs. Gross pathologic changes were characterized by myocarditis (diffuse or focal pallor of the myocardium), pulmonary congestion, emphysema, oedema and thoracic fluid. The EMCV was isolated and recognized as the causative agent of both outbreaks. The first outbreak in particular was associated with a rodent plague, confirming that rats are an important risk factor for the occurrence of the EMCV infection.

Competing Interests: The authors report no conflicts of interest.

Background: The bedside head impulse test (bHIT) is a clinical method of assessing the vestibulo-ocular reflex. It is a critical component of the bedside assessment of dizzy patients and helps differentiate acute stroke from vestibular neuritis. A previous study on senior Otolaryngology residents showed poor competence in performing and interpreting the bHIT and called for specific evaluations in the Competency By Design (CBD) curriculum to remedy this. This study aimed to assess whether those competencies have improved after full implementation of CBD in residency programs., Methods: Thirty post-graduate year 4 Otolaryngology residents in Canada were evaluated on the use of the bHIT using a written multiple-choice question (MCQ) examination, interpretation of bHIT videos, and performance of a bHIT. Ratings of bHIT performance were completed by 2 expert examiners (DT, DL) using the Ottawa Clinic Assessment Tool., Results: Only 6.7% (rater DT) and 20% (rater DL) of residents were found able to perform the bHIT independently. Inter-rater reliability was moderate (0.55, intraclass correlation). Mean scores were 70% (13.4% standard deviation) for video interpretation and 59% (20.6% standard deviation) for multiple-choice questions. Video interpretation scores did not correlate with bHIT ratings (Pearson r  = 0.11), but MCQs and bHIT ratings did correlate moderately (Pearson r = 0.52).Comparing to the prior study, residents performed worse on the bHIT (3.14 average score vs 3.64, P  < .01) and fewer residents performed the bHIT independently (6.7% vs 22%-rater DT, 20% vs 39%-rater DL). Residents also performed worse on MCQs (58.7% vs 70.9%, P = 0.038), though similarly on video interpretation (70% vs 65%, P  = .198)., Conclusion: Fourth year OTL-HNS residents in Canada are not competent in performing the bHIT. These findings have implications for refining competency-based curricula in the evaluation of critical physical exam skills., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: Stroke presenting as dizziness is a diagnostic challenge in frontline settings, given the multitude of benign conditions that present similarly. The risk of stroke after episodic dizziness is unknown, leading to divergent guidance on optimal workup and management. Prior TIA risk scores have shown a history of dizziness is a negative predictor of subsequent stroke. Our objective was to assess the subsequent stroke risk within 90 days following emergency department assessment (ED) for isolated dizziness diagnosed as TIA during the index visit., Methods: We conducted prospective, multicenter cohort studies at 13 Canadian EDs over 11 years. We enrolled patients diagnosed with TIA and compared patients with isolated dizziness to those with other neurological deficits. Our primary outcome was subsequent stroke within 90 days. Secondary outcomes were subsequent stroke within 2, 7, and 30 days, respectively, as well as subsequent TIA within 90 days., Results: Only 4/483 (0.8%) patients with isolated dizziness had a stroke within 90 days compared to 320/11024 (2.9%) of those with any focal neurological sign or symptom (RR 0.29, 95% CI 0.11-0.76). Over the first 90 days, the two groups differ significantly in their probability of stroke (p = 0.007). Subsequent TIA was also significantly less common in the isolated dizziness group (1.7% vs. 5.6%, p = 0.001) with a relative risk of 0.30 (95% CI 0.15-0.60)., Conclusion: The risk of subsequent stroke following ED presentation for TIA is low when the presenting symptoms are isolated dizziness., (© 2022. The Author(s), under exclusive licence to Canadian Association of Emergency Physicians (CAEP)/ Association Canadienne de Médecine d'Urgence (ACMU).)

Objective: Benign paroxysmal positional vertigo (BPPV) is commonly attributed to displaced otoconia. These have been shown to have biomineralization close to that of bone, and vitamin D deficiency has been associated with BPPV. We aim to systematically review the available literature on vitamin D supplementation and BPPV intensity and recurrence in adults., Databases Reviewed: PubMed, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Current Controlled Trials, and ClinicalTrials.gov., Methods: We systematically reviewed the available literature from 1947 to April 2020. The study protocol was registered in the PROSPERO database (trial registration: CRD42020183195)., Results: A total of 179 abstracts were identified and screened by two independent reviewers. Based on inclusion and exclusion criteria, six studies were selected and subjected to a quality assessment. In one randomized clinical trial (RCT), vitamin D supplementation was found to reduce annual recurrence rate of vertigo in patient with BPPV and subnormal serum vitamin D levels compared with placebo (odds ratio, 0.69; 95% confidence interval, 0.54-0.90). Non-RCTs demonstrated the possibility of a null effect in the random effects model (odds ratio, 0.08; 95% confidence interval, 0.00-1.56). The RCT considered as low risk of bias. All of the nonrandomized studies were assessed as serious risk of bias., Conclusions: The intervention studies identified consistently demonstrated a decrease in BPPV recurrence with supplementation of vitamin D in patients with subnormal vitamin D levels. Although there is a paucity of high-quality studies, the present literature does highlight a role for optimization of vitamin D levels in patients with BPPV., Competing Interests: The authors disclose no conflicts of interest., (Copyright © 2022, Otology & Neurotology, Inc.)

We present a clinical reasoning case of 42-year-old male with a history of type 1 diabetes who presented to hospital with decreased level of consciousness. We review the approach to coma including initial approach to differential diagnosis and investigations. After refining the diagnostic options based on initial investigations, we review the clinical decision-making process with a focus on narrowing the differential diagnosis, further investigations, and treatment., Competing Interests: Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2022.)

Background: Persistent Postural Perceptual Dizziness (PPPD) is a newly defined condition which was added to the International Classification of Vestibular Disorders in 2017. Little is known about its impact on patients., Objective: The goal of this study was to analyze the symptomology, epidemiology and impact of PPPD on patients., Methods: A retrospective chart review was done to identify patients who attended the Multidisciplinary Dizziness Clinic (MDC) and were diagnosed with PPPD. Responses to demographic questions, health-related quality of life surveys and several well-validated questionnaires commonly used to assess dizziness severity were analyzed., Results: One hundred patients were diagnosed with PPPD between March 2017 and January 2019, of which 80%(80/100) were females. The average Dizziness Handicap Index score was 60.3±19.0. Responses to the Patient Health Questionnaire classified 53 patients (53/99;53.5%) as moderately to severely depressed. Sixty-four patients (64/100;64.0%) were minimally or mildly anxious according to the Generalized Anxiety Disorder scale. The average Vertigo Symptom Scale score was 24.1/60. The average Situational Vertigo Questionnaire score was 2.00. Forty-nine (49/100;49.0%) patients had migraine symptoms according to the Migraine Screen Questionnaire., Conclusions: In conclusion, patients with PPPD display important handicap and an elevated risk of depression, anxiety and migraines.

Competing Interests: The authors report no conflicts of interest.

Objective: To assess the usefulness of head and neck computed tomography angiogram for the investigation of isolated dizziness in the emergency department in detecting significant acute findings leading to a change in management in comparison to non-contrast computed tomography scan of the head., Methods: Patients presenting with isolated dizziness in the emergency department investigated with non-contrast computed tomography and computed tomography angiogram over the span of 36 months were included. Findings on non-contrast computed tomography were classified as related to the emergency department presentation versus unrelated/no significant abnormality. Similarly, computed tomography angiogram scans were classified as positive or negative posterior circulation findings., Results: One hundred and fifty-three patients were imaged as a result of emergency department presentation with isolated dizziness. Fourteen cases were diagnosed clinically as of central aetiology. Non-contrast computed tomography was positive in three patients, all with central causes with sensitivity 21.4%, specificity 100%, positive predictive value 100%, negative predictive value 92.6% and accuracy 92.8%. Computed tomography angiogram was positive for angiographic posterior circulation abnormalities in five cases, and only two of them had a central cause of dizziness, with sensitivity 14.3%, specificity 97.7%, positive predictive value 40%, negative predictive value 91.46% and accuracy 92.1%., Conclusion: Both non-contrast computed tomography and computed tomography angiogram of the head and neck have low diagnostic yield for the detection of central causes of dizziness, However, non-contrast computed tomography has higher sensitivity and positive predictive value than computed tomography angiogram, implying a lack of diagnostic advantage from the routine use of computed tomography angiogram in the emergency department for the investigation of isolated dizziness. Further studies are required to determine the role of computed tomography angiogram in the work-up of isolated dizziness in the emergency department.

Background: Obstructive sleep apnea (OSA) has been linked to vestibular dysfunction, but no prior studies have investigated the relationship between Persistent Postural-Perceptual Dizziness (PPPD), a common cause of chronic dizziness, and OSA., Objective and Methods: We determined the frequency of OSA in an uncontrolled group of PPPD patients from a tertiary dizziness clinic based on polysomnogram (PSG). We then assessed the sensitivity and specificity of common OSA questionnaires in this population., Results: Twenty-five patients with PPPD underwent PSG (mean age 47, 60% female, mean BMI 29.5). A majority, or 56%, of patients were diagnosed with OSA, and in most, the OSA was severe. OSA patients were older (56 years versus 40 years, p = 0.0006) and had higher BMI (32 versus 26, p = 0.0078), but there was no clear gender bias (56% versus 64% female, p = 1.00). The mean sensitivity and specificity of the STOP BANG questionnaire for detecting OSA was 86% and 55%, respectively. Sensitivity and specificity of the Berlin Questionnaire was 79% and 45%, respectively., Conclusions: The prevalence of OSA was much higher in our small PPPD group than in the general population. Screening questionnaires appear to demonstrate good sensitivity to detect PPPD patients at risk of OSA in this small study. Future studies should confirm these findings and determine whether treatment of OSA improves symptoms in PPPD.

Introduction: Menière's Disease (MD) is a disorder of the inner ear consisting of episodic attacks of vertigo associated with aural fullness, tinnitus, and fluctuating hearing loss. Hearing levels in MD can often fluctuate over time, and may eventually decline permanently in a step-wise fashion. There are no current studies examining daily hearing fluctuations for prolonged periods in patients with MD. Portable audiometry has the potential to allow the patient to monitor their hearing on a daily basis without attending a center for formal audiology. The objective of this pilot study was to assess feasibility of using iPad-based audiometry on a daily basis to capture hearing fluctuations in a small sample of adult patients with active MD., Methods: We recruited five patients with active MD as defined by current diagnostic criteria (International Classification of Vestibular Disease 2015). "Active" MD was defined as the patient having had at least one typical Menière's episode within the last 4 weeks. Patients were trained on how to use the portable audiometer and asked to perform at least daily audiograms for 3 months. Patients were asked to manually track vertigo attacks in a diary. Qualitative feedback was obtained from each patient at each monthly visit. For each patient, individual pure tone thresholds at each frequency and pure-tone averages (PTA) were analyzed for maximum and minimum values and interquartile ranges., Results: There were four women and one man, with an average age of 49.8 years. Duration of MD ranged from 4 months to 5 years. None of the patients experienced any technical difficulties performing the testing at home. The average duration of each test was 4.2 minutes, with the longest test taking 19.2 minutes. Patients completed between 45 and 102 tests, with an average of 72. The interquartile range for the PTA ranged from 2.5 to 25 dB for affected ears, and 0 to 6.25 dB for unaffected ears with maximums ranging from 5 to 35 dB in affected ears, and 0 to 10 dB in unaffected ears., Conclusions: Daily portable audiometry is feasible in patients with MD. Future studies are planned to further analyze hearing fluctuations in MD with respect to frequencies affected, relationship to vertigo attacks, and response to treatments. Understanding hearing fluctuations in MD may aid refinement of diagnostic criteria and improve prognostication for long-term hearing loss, with a goal of informing treatments that might improve final hearing outcome.

Background: The bedside head impulse test (bHIT) is a clinical method of assessing the vestibulo-ocular reflex (VOR). It is a critical component of the bedside assessment of dizzy patients, and can help differentiate acute stroke from vestibular neuritis. However, there is evidence showing the bHIT is often not performed in appropriate clinical settings or is performed poorly. To date, there have been no studies evaluating the bHIT competence of graduating physicians., Methods: 23 final year Otolaryngology -Head &Neck Surgery (OTL-HNS) residents in Canada were evaluated on the use of bHIT using a written multiple-choice examination, interpretation of bHIT videos, and performance of a bHIT. Ratings of subject bHIT performance were completed by two expert examiners (DT, DL) using the previously published Ottawa Clinic Assessment Tool (OCAT)., Results: Using a cut-off of an OCAT score of 4 or greater, only 22% (rater DT) and 39% (rater DL) of residents were found able to perform the bHIT independently. Inter-rater reliability was fair (0.51, interclass correlation). The mean scores were 65% (14.1% standard deviation) on the video interpretation and 71% (20.2% standard deviation) on the multiple-choice questions. The scores on multiple choice examination did not correlate with bHIT ratings (Pearson r = 0.07) but there was fair correlation between video interpretation and bHIT ratings (Pearson r = 0.45)., Conclusion: Final year OTL-HNS residents in Canada are not adequately trained in performing the bHIT, though low interrater reliability may limit the evaluation of this bedside skill. Multiple choice examinations do not reflect bHIT skill. These findings have implications for development of competency-based curricula and evaluations in Canada in critical physical exam skills.

Background: In the Canadian health care system, determining overall costs associated with a particular diagnostic subgroup of patients, in this case dizzy patients, is the first step in the process of determining where costs could be saved without compromising patient care. This study is the first Canadian study that evaluates these costs at a tertiary care hospital and will allow for the extrapolation of cost data for other similar academic health science centers, regional health initiatives, and provincial healthcare planning structures., Methods: We conducted a retrospective cohort study of patients of any age presenting to The Ottawa Hospital (TOH), a tertiary care hospital, between January 1st, 2009 and December 31st , 2014 with a main diagnosis of dizziness or dizziness-related disease. De-identified patient information was acquired through TOH Data Warehouse and included a patient's sex, age, arrival and departure dates, Elixhauser co-morbidity score, location of presentation (emergency department or admitted inpatient) presenting complaint, final diagnosis code, any procedure codes linked to their care, and the direct and indirect hospital costs linked with any admission. We derived the mean hospital costs and 95% confidence interval for each diagnosis. We obtained the number of patients who were diagnosed with dizziness within Ontario in year 2015-16 from Canadian Institute for Health Information (CIHI). A simple frequency multiplication was performed to estimate the total cost burden for Ontario based on the cost estimate for the same year obtained from TOH. Cost data were presented in 2017 Canadian dollars., Results: The average total hospital cost per patient with dizziness for the entire cohort is $450 (SD = $1334), with ED only patients costing $359 (SD = $214). The total estimated hospital cost burden of dizziness in Ontario is $31,202,000 (95% CI $29,559,000 - 32,844,000)., Conclusions: The estimated annual costs of emergency department ambulatory and inpatient dizziness in Ontario was calculated to be approximately 31 million dollars per year. This is the first step in identifying potential areas for cost savings to aid local and provincial policy-makers in allocation of health care spending.

Objective: To examine the effects of body-weight supported treadmill training (BWSTT) on functional ability and quality of life in patients with progressive multiple sclerosis (MS) of high disability., Design: Before-after trial., Setting: Exercise rehabilitation research center., Participants: Patients with progressive MS (N=6; 5 primary progressive, 1 secondary progressive) with high disability (mean±SD expanded disability status scale, [EDSS]=6.9±1.07). All participants completed the trial., Interventions: Subjects completed 36 sessions of BWSTT (30-min sessions, 3×wk) over 12 weeks., Main Outcome Measures: Outcome measures included functional ability assessed by EDSS and Multiple Sclerosis Functional Composite (MSFC). Quality of life and fatigue were assessed by the MS Quality of Life-54 (MSQoL-54) and the Modified Fatigue Impact Scale (MFIS), respectively. All tests were administered at baseline and after 12 weeks of training., Results: All participants progressively improved training intensity; treadmill walking speed increased (34%; P<.001), and percent body weight support was reduced (42%; P<.001). A significant improvement in both physical (P=.02) and mental (P=.01) subscales of the MSQoL-54 was found. Fatigue was nonsignificantly reduced by 31% (P=.22); however, a large effect size (ES) was noted (ES=-.93). Functional ability remained stable with nonsignificant improvements in MSFC (P=.35; ES=.23) and EDSS (P=.36; ES=-.08) scores., Conclusions: Twelve weeks of BWSTT produces beneficial effects on quality of life and potentially reduces fatigue in patients with primary progressive MS of high disability level. Larger trials will be required to confirm these findings and to evaluate further the effects of BWSTT in progressive MS., (Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)