Evaluating the Prognostic Implication of the Collins Histology Scoring System in a Pediatric Eastern Ontario Population With Eosinophilic Esophagitis

Introduction: Collins et al developed a histology scoring system (EoE HSS) to assess multiple pathologic features. The aim of this study is to identify if the EoE HSS can better detect endoscopic and symptom improvement vs the Peak Eosinophilic Count (PEC). Methods: A retrospective chart review was performed for patients during 2014–2016. All patients ≤18 years old with a diagnosis of EoE and whose records included initial and follow-up upper gastrointestinal endoscopies were included. Severity and extent of endoscopic features were scored using 8 parameters, from normal to maximum change for each location of the esophageal biopsy. Results: Forty patients with EoE were included in the study, of which 35 (87.5%) patients demonstrated symptom and 25 (62.5%) endoscopic improvement at the time of follow-up. In the proximal esophagus, the EoE HSS outperformed the change in eosinophil count of the Children’s Hospital of Eastern Ontario (CHEO) practice in predicting endoscopic improvement by 16.8% when examining the change in grade and 17.1% when examining the change in stage scores. Conclusions: At our institution, adoption of the EoE HSS in assessing biopsies of EoE patients might be warranted, compared to the traditional practice. However, a bigger sample size may give a more robust difference in all locations.

Effects of land use and weather on the presence and abundance of mosquito-borne disease vectors in a urban and agricultural landscape in Eastern Ontario, Canada

Weather and land use can significantly impact mosquito abundance and presence, and by consequence, mosquito-borne disease (MBD) dynamics. Knowledge of vector ecology and mosquito species response to these drivers will help us better predict risk from MBD. In this study, we evaluated and compared the independent and combined effects of weather and land use on mosquito species occurrence and abundance in Eastern Ontario, Canada. Data on occurrence and abundance (245,591 individuals) of 30 mosquito species were obtained from mosquito capture at 85 field sites in 2017 and 2018. Environmental variables were extracted from weather and land use datasets in a 1-km buffer around trapping sites. The relative importance of weather and land use on mosquito abundance (for common species) or occurrence (for all species) was evaluated using multivariate hierarchical statistical models. Models incorporating both weather and land use performed better than models that include weather only for approximately half of species (59% for occurrence model and 50% for abundance model). Mosquito occurrence was mainly associated with temperature whereas abundance was associated with precipitation and temperature combined. Land use was more often associated with abundance than occurrence. For most species, occurrence and abundance were positively associated with forest cover but for some there was a negative association. Occurrence and abundance of some species (47% for occurrence model and 88% for abundance model) were positively associated with wetlands, but negatively associated with urban ( Culiseta melanura and Anopheles walkeri ) and agriculture ( An. quadrimaculatus, Cs. minnesotae and An. walkeri ) environments. This study provides predictive relationships between weather, land use and mosquito occurrence and abundance for a wide range of species including those that are currently uncommon, yet known as arboviruses vectors. Elucidation of these relationships has the potential to contribute to better prediction of MBD risk, and thus more efficiently targeted prevention and control measures.

Predicting water quality trends resulting from forest cover change in an agriculturally dominated river basin in Eastern Ontario, Canada

Agricultural extensification and forest cover loss can significantly impact aquatic ecosystems. This study considered the conversion of forests to agriculture (and vice versa) in an agriculturally dominated watershed in Eastern Ontario, Canada. A series of de- and reforestation scenarios were developed, and water quantity/quality simulations were executed using the Soil and Water Assessment Tool (SWAT) using 30 years of real-world weather observations. Results indicated that streamflow and sediment loads were not sensitive to forest loss, while continuing the recent rate of deforestation of 0.8% (0.2% of the watershed area) per year would, by 2032, increase annual loads of nitrate by 5.6%, total nitrogen by 1.5%, and total phosphorus by 6.8%. Additionally, the same land-use scenarios were simulated with the inclusion of vegetated filter strips (VFS) and grassed waterways. Some reforestation scenarios were sufficient to reduce total nitrogen concentrations below water quality guidelines, particularly under the combined effect of VFSs along all river reaches. However, meeting water quality guidelines for total phosphorus concentrations requires additional improvements to management practices beyond those simulated here.

Mapping the Habitat Suitability of West Nile Virus Vectors in Southern Quebec and Eastern Ontario, Canada, with Species Distribution Modeling and Satellite Earth Observation Data

Transmission of vector-borne diseases (VBDs) relies on the presence of their vectors. Good knowledge of their habitat distribution could inform of their presence and then the potential transmission risk. In Canada, West Nile virus (WNV), a VBD transmitted by mosquitoes of the Culex genus to birds, humans, and other mammals, was first reported in 2002. Since then, human cases have been reported every year. To reduce the health burden of the disease and to guide the vector control efforts, this work aims to provide a map of habitat suitability of the main vectors of WNV, Culex pipiens-restuans, in southern Quebec and eastern Ontario at 30 m spatial resolution. Landsat 8-OTI/TIRS images were combined with existing geographical data to characterize vegetated and paved areas in urban and peri-urban areas and to create a land use land cover map related to environmental determinants of Culex pipiens-restuans. Landscape metrics were calculated to characterize the neighborhood environment. They were used with 1008 presence sites of the vectors to build species distribution models with Maxent, a model based on the maximum entropy principle, and to predict habitat suitability for Culex pipiens-restuans in the study area. The performance of the models was very good, with a mean area under the curve of 0.92 and a continuous Boyce index of 0.97. A habitat suitability map of the whole study area was created for Culex pipiens-restuans. The resulting map and environment analysis highlight the importance of the edge of vegetation and mixed or paved areas for the bio-ecology of Culex pipiens-restuans.

Detection of the Novel SARS-CoV-2 European Lineage B.1.177 in Ontario, Canada

ABSTRACTBackgroundTravel-related dissemination of SARS-CoV-2 continues to contribute to the global pandemic. A novel SARS-CoV-2 lineage (B.1.177) reportedly arose in Spain in the summer of 2020, with subsequent spread across Europe linked to travel by infected individuals. Surveillance and monitoring through the use of whole genome sequencing (WGS) offers insights into the global and local movement of pathogens such as SARS-CoV-2 and can detect introductions of novel variants.MethodsWe analyzed the genomes of SARS-CoV-2 sequenced for surveillance purposes from specimens received by Public Health Ontario (Sept 6 – Oct 10, 2020), collected from individuals in eastern Ontario. Taxonomic lineages were identified using pangolin (v2.08) and phylogenetic analysis incorporated publicly available genomes covering the same time period as the study sample. Epidemiological data collected from laboratory requisitions and standard reportable disease case investigation was integrated into the analysis.ResultsGenomic surveillance identified a COVID-19 case with SARS-CoV-2 lineage B.1.177 from an individual in eastern Ontario in late September, 2020. The individual had recently returned from Europe. Genomic analysis with publicly available data indicate the most closely related genomes to this specimen were from Southern Europe. Genomic surveillance did not identify further cases with this lineage.ConclusionsGenomic surveillance allowed for early detection of a novel SARS-CoV-2 lineage in Ontario which was deemed to be travel related. This type of genomic-based surveillance is a key tool to measure the effectiveness of public health measures such as mandatory self-isolation for returned travellers, aimed at preventing onward transmission of newly introduced lineages of SARS-CoV-2.