Symptoms associated with a positive result for a swab for SARS-CoV-2 infection among children in Alberta

BACKGROUND:Research involving children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has primarily focused on those presenting to emergency departments. We aimed to determine the symptoms most commonly associated with a positive result for a SARS-CoV-2 swab among community-based children.METHODS:We conducted an observational study among children tested and followed for SARS-CoV-2 infection using nasal, nasopharyngeal, throat or other (e.g., nasopharyngeal aspirate or tracheal secretions, or unknown) swabs between Apr. 13 and Sept. 30, 2020, in Alberta. We calculated positive likelihood ratios (LRs) for self-reported symptoms and a positive SARS-CoV-2 swab result in the entire cohort and in 3 sensitivity analyses: all children with at least 1 symptom, all children tested because of contact tracing whether they were symptomatic or not and all children 5 years of age or older.RESULTS:We analyzed results for 2463 children who underwent testing for SARS-CoV-2 infection; 1987 children had a positive result and 476 had a negative result. Of children with a positive test result for SARS-CoV-2, 714 (35.9%) reported being asymptomatic. Although cough (24.5%) and rhinorrhea (19.3%) were 2 of the most common symptoms among children with SARS-CoV-2 infection, they were also common among those with negative test results and were not predictive of a positive test (positive LR 0.96, 95% confidence interval [CI] 0.81–1.14, and 0.87, 95% CI 0.72–1.06, respectively). Anosmia/ageusia (positive LR 7.33, 95% CI 3.03–17.76), nausea/vomiting (positive LR 5.51, 95% CI 1.74–17.43), headache (positive LR 2.49, 95% CI 1.74– 3.57) and fever (positive LR 1.68, 95% CI 1.34–2.11) were the symptoms most predictive of a positive result for a SARS-CoV-2 swab. The positive LR for the combination of anosmia/ageusia, nausea/vomiting and headache was 65.92 (95% CI 49.48–91.92).INTERPRETATION:About two-thirds of the children who tested positive for SARS-CoV-2 infection reported symptoms. The symptoms most strongly associated with a positive SARS-CoV-2 swab result were anosmia/ageusia, nausea/vomiting, headache and fever.

The refrain that “children are not small adults” certainly seems to apply in the context of coronavirus disease 2019 (COVID-19). Children are less likely to become infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) than adults and seem to experience less severe symptoms and have better prognoses.^1–4 However, some studies have suggested that reduced disease severity in children leads to them being less likely to undergo testing.⁵ Three 2020 studies highlighted that COVID-19 symptoms in children are similar to those of other acute respiratory illnesses, with fever, cough, nasal congestion, fatigue and runny nose predominating. ^6–8 On Sept. 15, 2020, the Centers for Disease Control and Prevention reported death to be an uncommon outcome in people younger than 21 years of age (0.08% of all deaths).⁹Beyond an understanding of what symptoms most commonly present in children, health care professionals and public health policy-makers could benefit from knowing which presenting symptoms are most likely to be associated with SARS-CoV-2 infection. Many jurisdictions have implemented screening questionnaires for pediatric-dominated settings such as schools. We hypothesized that some symptoms in children are more likely than others to be associated with a positive result for a test for SARS-CoV-2. We therefore assessed symptom patterns among children in Alberta who were followed by Alberta Public Health and who had swabs taken for possible SARS-CoV-2 infection, comparing those with positive results and those with negative results to estimate symptom frequencies and prognostic import of symptoms in a large cohort and in 3 subgroups.     

Epigenetic effects in eukaryotic gene expression

In the broadest terms, epigenetic phenomena in eukaryotes depend on the interaction of alleles or repeated sequences or on the mitotic inheritance of chromatin states or methylation patterns. One of the most exciting aspects of the study of epigenetic phenomena is the insight that can be gained into the structure and assembly of higher-order chromatin structures, an important subject that has proved refractory to current biochemical methodologies. Rapid progress in the study of gene inactivation in fungi, plants, and invertebrates will provide new hypotheses to be tested in mammals. © 1994 Wiley-Liss, Inc.     

Cloning of Human and Mouse EBI1, a Lymphoid-Specific G-Protein-Coupled Receptor Encoded on Human Chromosome 17q12-q21.2

A lymphoid-specific member of the G-protein-coupled receptor family has been identified by PCR with degenerate oligonucleotides. We have determined that this receptor, also reported as the Epstein-Barr-induced cDNA EBI1, is expressed in normal lymphoid tissues and in several B- and T-lymphocyte cell lines. While the function and the ligand for EBI1 remain unknown, its sequence and gene structure suggest that it is related to the receptors that recognize chemoattractants, such as interleukin-8, RANTES, C5a, and fMet-Leu-Phe. Like the chemoattractant receptors, EBI1 contains intervening sequences near its 5′ end; however, EBI1 is unique in that both of its introns interrupt the coding region of the first extracellular domain. The gene is encoded on human chromosome 17q12-q21.2. None of the other G-protein-coupled receptors has been mapped to this region, but the C-C chemokine family has been mapped to 17q11-q21. The mouse EBI1 cDNA has also been isolated and encodes a protein with 86% identity to the human homolog.     

Obesity in South Africa: The South African Demographic and Health Survey

Objectives: To ascertain the anthropometric profile and determinants of obesity in South Africans who participated in the Demographic and Health Survey in 1998. Research Methods and Procedures: A sample of 13,089 men and women (age, ≥15 years) were randomly selected and then stratified by province and urban and nonurban areas. Height, weight, mid-upper arm circumference, and waist and hip circumference were measured. Body mass index (BMI) was used as an indicator of obesity, and the waist/hip ratio (WHR) was used as an indicator of abdominal obesity. Multivariate regression identified sociodemographic predictors of BMI and waist circumference in the data. Results: Mean BMI values for men and women were 22.9 kg/m² and 27.1 kg/m², respectively. For men, 29.2% were overweight or obese (≥25 kg/m²) and 9.2% had abdominal obesity (WHR ≥1.0), whereas 56.6% of women were overweight or obese and 42% had abdominal obesity (WHR >0.85). Underweight (BMI <18.5 kg/m²) was found in 12.2% of men and 5.6% of women. For men, 19% of the variation of BMI and 34% of the variation in waist circumference could be explained by age, level of education, population group, and area of residence. For women, these variables explained 16% of the variation of BMI and 24% of the variation in waist circumference. Obesity increased with age, and higher levels of obesity were found in urban African women. Discussion: Overnutrition is prevalent among adult South Africans, particularly women. Determinants of overnutrition include age, level of education, ethnicity, and area of residence.     

Evidence for strong assortative mating,limited gene flow,and strong differentiation across the blue‐footed/Peruvian booby hybrid zone in northern Peru

Hybrid zones represent natural laboratories in which the processes of divergence and genetic isolation can be examined. The generation and maintenance of a hybrid zone requires mispairing and successful reproduction between organisms that differ in one or more heritable traits. Understanding the dynamics of hybridization between two species requires an understanding of the extent to which they have diverged genetically, the frequency of misparing and hybrid production, and the extent of introgression. Three hundred and twenty one blue‐footed Sula nebouxii and Peruvian S. variegata boobies from the eastern tropical Pacific Ocean were analyzed using 19 putatively neutral genetic markers to evaluate interspecific differentiation, to classify morphological hybrids using Bayesian assignments, and to characterize hybridization using cline theory and Bayesian assignments. The species were well differentiated at mitochondrial and nuclear microsatellites, the hybrid zone was bimodal (contained a high frequency of each parental species but a low frequency of hybrids), and morphologically intermediate individuals were most likely F1 hybrids resulting from mating between female Peruvian boobies and male blue‐footed boobies. Clines in allele frequency could be constrained to share a common geographic centre but could not be constrained to share a common width. Peruvian and blue‐footed boobies hybridize infrequently, potentially due to strong premating reproductive isolation; however, backcrossing appears to facilitate introgression from blue‐footed to Peruvian boobies in this hybrid system.     

Gene expression analyses in maize inbreds and hybrids with varying levels of heterosis

Background  

Heterosis is the superior performance of F₁ hybrid progeny relative to the parental phenotypes. Maize exhibits heterosis for a wide range of traits, however the magnitude of heterosis is highly variable depending on the choice of parents and the trait(s) measured. We have used expression profiling to determine whether the level, or types, of non-additive gene expression vary in maize hybrids with different levels of genetic diversity or heterosis.