ABSTRACT
Various kinds of field crops growing on two commercial farms in the Whitehorse area of the southern Yukon Territory were surveyed for diseases in summer 2020 by staff of the Agriculture Branch of the Government of Yukon. They included barley, wheat, canola, beets, broccoli, cabbage, carrots, potatoes and turnips. Fields were visited one or more times during July and August. The incidence and severity of diseases were visually assessed on a crop-by-crop basis and samples were collected for laboratory analysis of the pathogens present, if any. Both infectious and non-infectious diseases were present on most crops. The infectious diseases were caused by various species of plant pathogenic bacteria and fungi that were common on these crops growing in other areas of Canada. INTRODUCTION AND METHODS: The 2020 field crop disease survey is believed to be the first organized study of its kind on agricultural crops in the Territory. In his book, "An Annotated Index of Plant Diseases in Canada . . . ", I.L. Conners lists over 300 records of plant diseases on trees, shrubs, herbs and grasses in the Yukon that were published by individuals who were surveying forests and native vegetation mainly for federal government departments, universities and other agencies (Conners 1967). The objectives of the 2020 survey were: (1) to determine the kinds and levels of diseases on selected Yukon crops, (2) to identify the major pathogen species attacking Yukon crops, and (3) to use the results to plan future surveillance activities aimed at helping producers to improve their current disease management programs. All of the fields included in the 2020 survey were situated on two commercial farms, which were designated as Farm #1 and #2, in the Whitehorse area in the southern Yukon (Fig. 1). The crops surveyed included cereals (barley and wheat), oilseeds (canola) and vegetables (beets, broccoli, cabbage, carrots, potatoes and turnips). Fields were visited one or more times in the mid- to late growing season (July/August) at a time when damage from diseases was most noticeable. Symptoms were visually assessed on a crop-by-crop basis by determining their incidence and severity. Incidence was represented by the percentage of plants, leaves, heads, kernels, etc., damaged in the target crop, while severity was estimated to be the proportion of the leaf, fruit, head, root/canopy area, etc., affected by a specific disease as follows: Proportion of the canopy affected based on a 0-4 rating scale, where: 0 = no disease symptoms, 1 = 1-10% of the crop canopy showing symptoms;2 = 11-25% showing symptoms, 3 = 26- 50% showing symptoms, and 4 = > 50% showing symptoms. Photographs of affected plants were taken and sent to plant pathologists across Western Canada for their opinions on causation. Where possible, representative samples of plants with disease symptoms were packaged and sent to the Alberta Plant Health Lab (APHL) in Edmonton, AB for diagnostic analyses. Background information, such as the general cultural practices and cropping history, was obtained from the producers wherever possible. GPS coordinates were obtained for each field to enable future mapping Cereals: Individual fields of barley (11 ha) and wheat (30 ha) located at Farm #1 were surveyed. The barley was a two-row forage cultivar 'CDC Maverick', while the wheat was an unspecified cultivar of Canada Prairie Spring (CPS) Wheat. Plant samples were taken along a W-shaped transect for a total of five sampling points for the barley field (< 20 ha) and ten sampling points for the wheat field (> 20 ha). The first visit, which occurred on July 30, involved visual inspection and destructive sampling wherein plants were collected and removed from the field for a detailed disease assessment at a lab space in Whitehorse. There, the roots were rinsed off and the plants were examined for disease symptoms. The second visit to these fields, which occurred on August 27, only involved visual examination of the standing crop. Oilseeds: A single 40 ha field of Polish canola (cv. 'Synergy') was examined o
ABSTRACT
Background During the first wave of the pandemic in 2020, Covid-19 symptoms of cough, fever and loss of taste/smell were identified in the adult population and aided diagnostic PCR testing. However, children with similar symptoms appeared less likely to test positive or to develop severe disease. As part of a multi-centre observational cohort study from 16th April 2020 to 3rd July 2020, 992 paediatric participants aged 2-15 years, were recruited and underwent SARSCoV- 2 antibody testing and provided symptom data. Objectives To identify the proportion of healthy children who demonstrated antibody response to SARS-CoV-2 infection in this cohort of healthcare worker's children. To identify the symptoms experienced by participants who had the presence of SARS-CoV-2 antibodies. To assess if there was correlation between different symptoms experienced and SARS-CoV-2 antibody titres in a paediatric population. Methods 1007 participants were enrolled and 992 were included in the final analysis. Participants were identified across 5 UK sites-Belfast, Glasgow, Cardiff, Manchester and London. All participants were healthy children of NHS healthcare workers. Participants underwent phlebotomy and provided blood samples for SARS-CoV-2 antibody testing and information on their symptoms in the form of an electronic case report form (CRF). Serum and/or plasma was tested for antibodies to SARS-CoV-2 using nucleocapsid and spike protein assays. Study data was recorded on a CRF using REDCap and information recorded included age, sex, previous health, recent symptoms and potential predictors of presence of SARs-CoV-2 antibodies including contact with confirmed or suspected cases. Results Of the 992 patients included, 962/992 (97%) had complete CRFs. The median age of study participants was 10.1 years (2.03-15.99yrs) and 51% were male. There were 68/992 participants with positive SARS-CoV-2 antibodies, giving a seroprevalence of 6.9%. Of those with positive SARSCoV- 2 antibody tests, 34/68 (50%) were asymptomatic. In the symptomatic participants (34/68), the most commonly reported symptoms were fever 21/68 (31%), gastrointestinal symptoms 13/68 (19%) and headache 12/68 (18%). The presence of fever, cough or change in smell/taste was reported by 26/68 (38%) of antibody positive participants. None of the participants experienced severe symptoms requiring hospital admission. One of the assays (Abbott Architect SARS-CoV-2 IgG assay), indicated a small but significant increase in mean antibody titres between asymptomatic 4.3 S/C (95% CI 3.4 to 5.2) and symptomatic participants 5.5 S/C (95% CI 4.7 to 6.2), but this was not replicated with Roche Elecsys or DiaSorin LIAISON assays which found no significant difference. Conclusions Following the first wave of the pandemic, 68/992 (6.9%) of children of healthcare workers in UK had evidence of previous SARS-CoV-2 infection. Importantly, only 50% of these children experienced symptoms and this highlights the potential for asymptomatic children to be missed by current NHS testing guidelines. The symptoms which adults often experience, namely pyrexia, cough and loss of taste/smell, were only experienced by 38% of children who had SARSCoV- 2 antibodies. These children were more likely to experience gastrointestinal symptoms or lethargy and headache and therefore raises the question of whether this should be factored into current symptomatic testing guidelines.