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Neuroscience and Biobehavioral Reviews Jun 2021Olfactory impairment is a common clinical motif across neurodevelopmental disorders, suggesting olfactory circuits are particularly vulnerable to disease processes and... (Review)
Review
Olfactory impairment is a common clinical motif across neurodevelopmental disorders, suggesting olfactory circuits are particularly vulnerable to disease processes and can provide insight into underlying disease mechanisms. The mouse olfactory bulb is an ideal model system to study mechanisms of neurodevelopmental disease due to its anatomical accessibility, behavioral relevance, ease of measuring circuit input and output, and the feature of adult neurogenesis. Despite the clinical relevance and experimental benefits, olfactory testing across animal models of neurodevelopmental disease has been inconsistent and non-standardized. Here we performed a systematic literature review of olfactory function testing in mouse models of neurodevelopmental disorders, and identified intriguing inconsistencies that include evidence for both increased and decreased acuity in odor detection in various mouse models of Autism Spectrum Disorder (ASD). Based on our identified gaps in the literature, we recommend direct comparison of different mouse models of ASD using standardized tests for odor detection and discrimination. This review provides a framework to guide future olfactory function testing in mouse models of neurodevelopmental diseases.
Topics: Adult; Animals; Autism Spectrum Disorder; Humans; Mice; Neurogenesis; Olfaction Disorders; Olfactory Bulb; Smell
PubMed: 33610612
DOI: 10.1016/j.neubiorev.2021.02.024 -
International Journal of Dermatology May 2021Since COVID-19 has become a pandemic, extensive literature has been produced. The commonest symptoms of COVID-19 disease are fever, cough, anosmia, and lymphocytopenia.... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Since COVID-19 has become a pandemic, extensive literature has been produced. The commonest symptoms of COVID-19 disease are fever, cough, anosmia, and lymphocytopenia. However, other apparently less common clinical symptoms have been described, including skin lesions. We conducted a systematic review to evaluate skin involvement in COVID-19.
METHODS
The authors performed a systematic review of literature, in accordance with the Preferred Reporting Items for Systematic and Meta-Analysis (PRISMA). The search was reiterated until May 06, 2020.
RESULTS
Overall, 1593 patients (M/F ratio: 1 : 9) with suspect of COVID-19 were examined. The mean age was 37.8 (range 0-91) years. Among the analyzed patients, 84 (5.3%) were pediatrics (<18 years). Chilblains are very common among skin lesions and represent almost half of all skin lesions reported (46%); in 75% of patients with cutaneous manifestation, the latter presented before other typical clinical manifestation of COVID-19. Vasculitis or thrombosis was identified in almost 70% of patients who suffered from skin manifestations.
CONCLUSION
The present study highlights the importance of skin involvement in COVID-19. Limbs should be examined to eventually foresee the onset of further typical symptoms. Chilblains can be considered typical features. Studies with higher scientific evidence are required.
Topics: COVID-19; Chilblains; Humans; Pandemics; Skin Diseases; Thrombosis; Vasculitis
PubMed: 33533036
DOI: 10.1111/ijd.15414 -
Brain, Behavior, & Immunity - Health May 2020Reports of neurological involvement during Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection course are increasingly described. The aim of this... (Review)
Review
OBJECTIVE
Reports of neurological involvement during Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection course are increasingly described. The aim of this review is to provide a clinical approach of SARS-CoV-2 neurological complications based on the direct or indirect (systemic/immune-mediated) role of the SARS-CoV-2 in their genesis.
METHODS
A review of the current literature has been carried out up to May 20th 2020 according to the PRISMA guidelines. All case series and reports of adult neurological manifestations associated to SARS-CoV-2 published in English were considered. Review and fundamental research studies on Coronaviruses neuroinvasive potential were analyzed to support pathogenic hypothesis and possible underlying mechanisms. Clinical patterns were subdivided into three groups according to putative underlying mechanisms: direct invasion of central or peripheral nervous system, systemic disorders leading to acute CNS injuries and post-infectious neurological syndromes (PINS).
RESULTS
Sixteen case series and 26 case reports for a total of 903 patients were identified presenting with neurological involvement during SARS-CoV-2 infection. Hypo/anosmia and dys/ageusia were found in 826 patients and mainly attributed to direct viral invasion. Cerebrovascular complications occurred in 51 patients and related to viral infection associated systemic inflammation. PINS were described in only 26 patients. A wide heterogeneity of these reports emerged concerning the extension of the clinical examination and ancillary exams performed.
CONCLUSIONS
Neurological complications of SARS-CoV-2 are mainly related to olfactory and gustatory sensory perception disorders through possible direct nervous system invasion while cerebrovascular disease and PINS are rare and due to distinct and indirect pathophysiological mechanisms.
PubMed: 33521692
DOI: 10.1016/j.bbih.2020.100094 -
American Journal of Otolaryngology 2021The aim of the study was to conduct a systematic review of the literature to investigate the time of onset and duration of symptoms of loss of smell and taste in...
OBJECTIVE
The aim of the study was to conduct a systematic review of the literature to investigate the time of onset and duration of symptoms of loss of smell and taste in patients diagnosed with COVID-19.
METHODS
Two independent authors performed a systematic review of the Medline/PubMed, SCOPUS, COCHRANE, Lilacs and Web of Science electronic databases. The time of onset and duration of symptoms were considered primary outcomes. The sex and age of individuals, the geographical location of the study, the prevalence of symptoms, other associated symptoms, associated comorbidities, and the impact on quality of life and eating habits were considered secondary outcomes.
RESULTS
Our search generated 17 articles. Many of the studies reported that the onset of anosmia and ageusia occurred 4 to 5 days after the manifestation of other symptoms of the infection and that these symptoms started to disappear after one week, with more significant improvements in the first two weeks.
CONCLUSION
The present study concludes that the onset of symptoms of loss of smell and taste, associated with COVID-19, occurs 4 to 5 days after other symptoms, and that these symptoms last from 7 to 14 days. Findings, however, varied and there is therefore a need for further studies to clarify the occurrence of these symptoms. This would help to provide early diagnosis and reduce contagion by the virus.
Topics: Ageusia; Anosmia; COVID-19; Humans; Time Factors
PubMed: 33445036
DOI: 10.1016/j.amjoto.2020.102889 -
Journal of Global Health Dec 2020It is of paramount importance to understand the transmission of SARS-CoV-2 in schools, which could support the decision-making about educational facilities closure or... (Meta-Analysis)
Meta-Analysis
BACKGROUND
It is of paramount importance to understand the transmission of SARS-CoV-2 in schools, which could support the decision-making about educational facilities closure or re-opening with effective prevention and control measures in place.
METHODS
We conducted a systematic review and meta-analysis to investigate the extent of SARS-CoV-2 transmission in schools. We performed risk of bias evaluation of all included studies using the Newcastle-Ottawa Scale (NOS).
RESULTS
2178 articles were retrieved and 11 studies were included. Five cohort studies reported a combined 22 student and 21 staff index cases that exposed 3345 contacts with 18 transmissions (overall infection attack rate (IAR): 0.08%, 95% confidence interval (CI) = 0.00%-0.86%). IARs for students and school staff were 0.15% (95% CI = 0.00%-0.93%) and 0.70% (95% CI = 0.00%-3.56%) respectively. Six cross-sectional studies reported 639 SARS-CoV-2 positive cases in 6682 study participants tested [overall SARS-CoV-2 positivity rate: 8.00% (95% CI = 2.17%-16.95%). SARS-CoV-2 positivity rate was estimated to be 8.74% (95% CI = 2.34%-18.53%) among students, compared to 13.68% (95% CI = 1.68%-33.89%) among school staff. Gender differences were not found for secondary infection (OR = 1.44, 95% CI = 0.50-4.14, = 0.49) and SARS-CoV-2 positivity (OR = 0.90, 95% CI = 0.72-1.13, = 0.36) in schools. Fever, cough, dyspnea, ageusia, anosmia, rhinitis, sore throat, headache, myalgia, asthenia, and diarrhoea were all associated with the detection of SARS-CoV-2 antibodies (based on two studies). Overall, study quality was judged to be poor with risk of performance and attrition bias, limiting the confidence in the results.
CONCLUSIONS
There is limited high-quality evidence available to quantify the extent of SARS-CoV-2 transmission in schools or to compare it to community transmission. Emerging evidence suggests lower IAR and SARS-CoV-2 positivity rate in students compared to school staff. Future prospective and adequately controlled cohort studies are necessary to confirm this finding.
Topics: Adolescent; COVID-19; Child; Cross-Sectional Studies; Disease Transmission, Infectious; Female; Humans; Male; SARS-CoV-2; Schools; Students
PubMed: 33437465
DOI: 10.7189/jogh.10.021104 -
Drug Discoveries & Therapeutics Jan 2021The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in 2019 in Wuhan, China. Clinically, respiratory tract symptoms as...
The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in 2019 in Wuhan, China. Clinically, respiratory tract symptoms as well as other organs disorders are observed in patients positively diagnosed coronavirus disease 2019 (COVID-19). In addition, neurological symptoms, mainly anosmia, ageusia and headache were observed in many patients. Once in the central nervous system (CNS), the SARS-CoV-2 can reside either in a quiescent latent state, or eventually in actively state leading to severe acute encephalitis, characterized by neuroinflammation and prolonged neuroimmune activation. SRAS-CoV-2 requires angiotensin-converting enzyme 2 (ACE2) as a cell entry receptor. The expression of this receptor in endothelial cells of blood-brain barrier (BBB) shows that SRAS-CoV-2 may have higher neuroinvasive potential compared to known coronaviruses. This review summarizes available information regarding the impact of SRAS-CoV-2 in the brain and tended to identify its potential pathways of neuroinvasion. We offer also an understanding of the long-term impact of latently form of SARS-CoV-2 on the development of neurodegenerative disorders. As a conclusion, the persistent infection of SRAS-CoV-2 in the brain could be involved on human neurodegenerative diseases that evolve a gradual process, perhapes, over several decades.
Topics: Animals; COVID-19; Central Nervous System Viral Diseases; Host-Pathogen Interactions; Humans; Neurodegenerative Diseases; Neurons; SARS-CoV-2; Viral Tropism; Virus Latency
PubMed: 33390561
DOI: 10.5582/ddt.2020.03106 -
The American Journal of the Medical... Feb 2021The presence of olfactory dysfunction or "loss of smell" has been reported as an atypical symptom in patients with coronavirus disease 2019 (COVID-19). We performed a... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The presence of olfactory dysfunction or "loss of smell" has been reported as an atypical symptom in patients with coronavirus disease 2019 (COVID-19). We performed a systematic review and meta-analysis of the available literature to evaluate the prevalence of "loss of smell" in COVID-19 as well as its utility for prognosticating the disease severity.
METHODS
An exhaustive search of the PubMed/Medline, Embase, Web of Science, Cochrane Library, LitCovid NIH, and WHO COVID-19 database was conducted through August 6, 2020. All studies reporting the prevalence of "loss of smell" (anosmia and/or hyposmia/microsmia) in laboratory-confirmed COVID-19 patients were included. Pooled prevalence for cases (positive COVID-19 through reverse transcriptase (RT-PCR) and/or serology IgG/IgM) and controls (negative RT-PCR and/or serology) was compared, and the odds ratio (OR), 95% confidence interval (CI) and the p-value were calculated. A p-value of <0.05 was considered statistically significant.
RESULTS
A total of 51 studies with 11074 confirmed COVID-19 patients were included. Of these, 21 studies used a control group with 3425 patients. The symptom of "loss of smell" (OR: 14.7, CI: 8.9-24.3) was significantly higher in the COVID-19 group when compared to the control group. Seven studies comparing severe COVID-19 patients with- and without "loss of smell" demonstrated favorable prognosis for patients with "loss of smell" (OR: 0.36, CI 0.27-0.48).
CONCLUSIONS
Olfactory dysfunction or "loss of smell" is a prevalent symptom in COVID-19 patients. Moreover, COVID-19 patients with "loss of smell" appear to have a milder course of the disease.
Topics: Anosmia; COVID-19; Humans; Smell
PubMed: 33349441
DOI: 10.1016/j.amjms.2020.09.017 -
Chemical Senses Dec 2020Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has currently infected over 6.5 million people worldwide.... (Meta-Analysis)
Meta-Analysis
Objective Sensory Testing Methods Reveal a Higher Prevalence of Olfactory Loss in COVID-19-Positive Patients Compared to Subjective Methods: A Systematic Review and Meta-Analysis.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has currently infected over 6.5 million people worldwide. In response to the pandemic, numerous studies have tried to identify the causes and symptoms of the disease. Emerging evidence supports recently acquired anosmia (complete loss of smell) and hyposmia (partial loss of smell) as symptoms of COVID-19, but studies of olfactory dysfunction show a wide range of prevalence from 5% to 98%. We undertook a search of Pubmed/Medline and Google Scholar with the keywords "COVID-19," "smell," and/or "olfaction." We included any study that quantified smell loss (anosmia and hyposmia) as a symptom of COVID-19. Studies were grouped and compared based on the type of method used to measure smell loss-subjective measures, such as self-reported smell loss, versus objective measures using rated stimuli-to determine if prevalence differed by method type. For each study, 95% confidence intervals (CIs) were calculated from point estimates of olfactory disturbances. We identified 34 articles quantifying anosmia as a symptom of COVID-19 (6 objective and 28 subjective), collected from cases identified from January 16 to April 30, 2020. The pooled prevalence estimate of smell loss was 77% when assessed through objective measurements (95% CI of 61.4-89.2%) and 44% with subjective measurements (95% CI of 32.2-57.0%). Objective measures are a more sensitive method to identify smell loss as a result of infection with SARS-CoV-2; the use of subjective measures, while expedient during the early stages of the pandemic, underestimates the true prevalence of smell loss.
Topics: Anosmia; COVID-19; Humans; Olfaction Disorders; Prevalence; Risk Factors; SARS-CoV-2
PubMed: 33245136
DOI: 10.1093/chemse/bjaa064 -
The Laryngoscope Apr 2021Olfactory dysfunction has been observed as one of the clinical manifestations in COVID-19 patients. We aimed to conduct a systematic review and meta-analysis to estimate... (Meta-Analysis)
Meta-Analysis
OBJECTIVES/HYPOTHESIS
Olfactory dysfunction has been observed as one of the clinical manifestations in COVID-19 patients. We aimed to conduct a systematic review and meta-analysis to estimate the overall pooled prevalence of olfactory dysfunction in COVID-19 patients.
STUDY DESIGN
Systematic review and meta-analyses.
METHODS
PubMed, Scopus, Web of Science, Embase, and Google Scholar databases were searched to identify studies published between 1 December 2019 and 23 July 2020. We used random-effects model to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I statistic and Cochran's Q test. Robustness of the pooled estimates was checked by different subgroup and sensitivity analyses This study is registered with PROSPERO (CRD42020183768).
RESULTS
We identified 1162 studies, of which 83 studies (n = 27492, 61.4% female) were included in the meta-analysis. Overall, the pooled prevalence of olfactory dysfunction in COVID-19 patients was 47.85% [95% CI: 41.20-54.50]. We observed olfactory dysfunction in 54.40% European, 51.11% North American, 31.39% Asian, and 10.71% Australian COVID-19 patients. Anosmia, hyposmia, and dysosmia were observed in 35.39%, 36.15%, and 2.53% of the patients, respectively. There were discrepancies in the results of studies with objective (higher prevalence) versus subjective (lower prevalence) evaluations. The discrepancy might be due to false-negative reporting observed in self-reported health measures.
CONCLUSIONS
The prevalence of olfactory dysfunction in COVID-19 patients was found to be 47.85% based on high-quality evidence. Due to the subjective measures of most studies pooled in the analysis, further studies with objective measures are advocated to confirm the finding.
LEVEL OF EVIDENCE
2 Laryngoscope, 131:865-878, 2021.
Topics: COVID-19; Humans; Olfaction Disorders; Prevalence
PubMed: 33219539
DOI: 10.1002/lary.29286 -
OTO Open 2020Loss of smell and taste are considered potential discriminatory symptoms indicating triaging for coronavirus disease 2019 (COVID-19) and early case identification.... (Review)
Review
OBJECTIVE
Loss of smell and taste are considered potential discriminatory symptoms indicating triaging for coronavirus disease 2019 (COVID-19) and early case identification. However, the estimated prevalence essential to guide public health policy varies in published literature. This meta-analysis aimed to estimate prevalence of smell and taste loss among COVID-19 patients.
DATA SOURCES
We conducted systematic searches of PubMed, Embase, Web of Science, and Google Scholar databases for studies published on the prevalence of smell and taste loss in COVID-19 patients.
REVIEW METHODS
Two authors extracted data on study characteristics and the prevalence of smell and taste loss. Random-effects modeling was used to estimate pooled prevalence. Subgroup analysis and meta-regression were conducted to explore potential heterogeneity sources. This study used PRISMA and MOOSE guidelines.
RESULTS
Twenty-seven of 32 studies reported a prevalence of loss of smell, taste, or both from a combined sample of 20,451 COVID-19 patients. The estimated global pooled prevalence of loss of smell among 19,424 COVID-19 patients from 27 studies was 48.47% (95% CI, 33.78%-63.29%). Loss of taste was reported in 20 studies and 8001 patients with an estimated pooled prevalence of 41.47% (95% CI, 3.13%-31.03%), while 13 studies that reported combined loss of smell and taste in 5977 COVID-19 patients indicated a pooled prevalence of 35.04% (95% CI, 22.03%-49.26%).
CONCLUSIONS
The prevalence of smell and taste loss among COVID-19 patients was high globally, and regional differences supported the relevance of these symptoms as important markers. Health workers must consider them as suspicion indices for empirical diagnosis of severe acute respiratory syndrome coronavirus 2 infection.
PubMed: 32964177
DOI: 10.1177/2473974X20957975