Symptoms and quality of life before, during, and after a SARS-CoV-2 PCR positive or negative test:data from Lifelines

This study evaluates to what extent symptoms are present before, during, and after a positive SARS-CoV-2 polymerase chain reaction (PCR) test, and to evaluate how the symptom burden and quality of Life (QoL) compares to those with a negative PCR test. Participants from the Dutch Lifelines COVID-19 Cohort Study filled-out as of March 2020 weekly, later bi-weekly and monthly, questions about demographics, COVID-19 diagnosis and severity, QoL, and symptoms. The study population included those with one positive or negative PCR test who filled out two questionnaires before and after the test, resulting in 996 SARS-CoV-2 PCR positive and 3978 negative participants. Nearly all symptoms were more often reported after a positive test versus the period before the test (p &lt; 0.05), except fever. A higher symptom prevalence after versus before a test was also found for nearly all symptoms in negatives (p &lt; 0.05). Before the test, symptoms were already partly present and reporting of nearly all symptoms before did not differ between positives and negatives (p &gt; 0.05). QoL decreased around the test for positives and negatives, with a larger deterioration for positives. Not all symptoms after a positive SARS-CoV-2 PCR test might be attributable to the infection and symptoms were also common in negatives.</p

Fatigue in patients with chronic disease:results from the population-based Lifelines Cohort Study

(1) To evaluate the prevalence of severe and chronic fatigue in subjects with and without chronic disease; (2) to assess to which extent multi-morbidity contributes to severe and chronic fatigue; and (3) to identify predisposing and associated factors for severe and chronic fatigue and whether these are disease-specific, trans-diagnostic, or generic. The Dutch Lifelines cohort was used, including 78,363 subjects with (n = 31,039, 53 ± 12 years, 33% male) and without (n = 47,324, 48 ± 12 years, 46% male) ≥ 1 of 23 chronic diseases. Fatigue was assessed with the Checklist Individual Strength-Fatigue. Compared to participants without a chronic disease, a higher proportion of participants with ≥ 1 chronic disease were severely (23% versus 15%, p < 0.001) and chronically (17% versus 10%, p < 0.001) fatigued. The odds of having severe fatigue (OR [95% CI]) increased from 1.6 [1.5–1.7] with one chronic disease to 5.5 [4.5–6.7] with four chronic diseases; for chronic fatigue from 1.5 [1.5–1.6] to 4.9 [3.9–6.1]. Multiple trans-diagnostic predisposing and associated factors of fatigue were found, explaining 26% of variance in fatigue in chronic disease. Severe and chronic fatigue are highly prevalent in chronic diseases. Multi-morbidity increases the odds of having severe and chronic fatigue. Several trans-diagnostic factors were associated with fatigue, providing a rationale for a trans-diagnostic approach

Sustainable control of internal fruit rot in bell peppers (Capsicum Annuum L.)

Since 2003, Belgian bell pepper growers are confronted with a new disease called internal fruit rot, which is caused by Fusarium species. The pathogen infects the fruit via the flowers and stays latent until ripening or even post harvest, after which fungal mycelium can develop and cause an internal and later external fruit rot. About 75% of the isolates obtained from diseased peppers belong to the Fusarium lactis species complex (FLASC) while F. oxysporum and F. proliferatum were less frequently isolated, 14% and 9%, respectively. The pathogenicity of these three Fusarium species was compared on two to four cultivars using assays involving fruit as well as flower inoculation. Differences in pathogenicity between the Fusarium species were most clearly observed after fruit inoculation, but these were not consistent with the results of flower inoculation, which is considered more representative. To better understand the latent phase of the infection process, and especially to investigate if there is a decline in the number of latent infections during the growing period, we determined the presence of Fusarium in the flowers and fruit at 10 time points between flowering and harvest using traditional surface disinfection and plating techniques using either natural infection or artificially inoculated (FLASC) flowers. This experiment was repeated at least three times during the growing season. To our surprise, the frequency of latently infected fruit stayed at a similar level during the entire growing process, indicating that there may be only limited opportunities to affect the amount of disease after the initial infection took place. One method to reduce the number of initial infections may be to remove the withering tissue such as the pistil and petals, as preliminary research showed these were saprophytically colonized with FLASC isolates. Such removal proved not successful in several experiments, indicating the infection process is quite fast and the number of airborne spores is insufficiently lowered by removal of these structures. Our study provided more insights into this pathosystem, which may result in opportunities for the sustainable control of internal fruit rot via prevention of flower infection and screening for disease resistance.status: publishe

Sustainable control of internal fruit rot in bell pepper: A multidisciplinary approach

An internal fruit rot disease of sweet peppers, first reported in Canada in 2000, later emerged as a significant disease of greenhouse-grown bell pepper worldwide. It is caused primarily by members of the Fusarium lactis species complex (FLASC) and to a lesser extent by Fusarium oxysporum and Fusarium proliferatum. After infection via the flowers, the fungus stays latent in the fruit until maturity. During ripening, the fungus starts to proliferate on the inside of the fruit. Later, sunken lesions appear on the outside. Nearly all growers are confronted with this problem to some extent, with an average annual yield loss estimated at 5% and seasonal peaks up to 20%. Despite the importance of the disease, particularly during years with high disease incidence, efficient control is lacking. A multidisciplinary approach is clearly needed. Here we report on the potential use of Biological Control Agents (BCA) and plant resistance elicitors as well as susceptibility trials of pepper varieties. Seven BCAs were active in vitro. These were tested under conventional greenhouse conditions. First, one-dayold flowers were separately inoculated with BCAs. One day later they were inoculated with FLASC. The infection incidence in two-week-old fruits and mature fruits was determined using surface disinfection and plating techniques. Two BCA isolates (one commercially available and one KUL isolate) reduced the number of infected fruits by 50%. Another strategy to reduce the initial infection of the flowers was tested, i.e. inducing plant resistance using elicitors. Three commercial elicitors were tested twice under greenhouse conditions and applied at recommended dose. The infection incidence was determined at 4 time points during fruit development. Surprisingly, no decline in the infection rate was observed. To evaluate the difference in susceptibility between pepper varieties, fruits of 12 varieties were pin-wounded and inoculated with a mycelium plug of FLASC. The lesion size on the yellow varieties was significantly larger than those on the red varieties. In addition, controlled in situ flower inoculations with FLASC were conducted on different varieties. Fruit infection was determined two weeks after inoculation and at harvest. Red and yellow cultivars were equally susceptible to infection but the final percentage of symptomatic fruit was significantly different between some varieties. Although no variety showed complete resistance, some had significantly less disease. The results were consistent with those of the previous year, suggesting these assays may give a good indication of varietal susceptibility. These studies showed that both BCAs and pepper variety can contribute to the multidisciplinary control of Fusarium internal fruit rot. When used with other measures (e.g. climatic control) yield loss may be reduced to a commercially acceptable level. Keywords: Capsicum annuum, BCA, elicitor, varietal susceptibilitystatus: publishe

Internal fruit rot (Fusarium spp.) of Greenhouse Bell Peppers

Since 2003 the cultivation of bell peppers in Belgium has to deal with a new disease that leads to internal fruit rot and is caused by Fusarium species. Infection takes place in the flowering stage. The pathogen stays latent during the growth of the fruit after which fungal mycelium can develop during ripening, but mostly after harvest, causing internal and later external fruit rot. Around 75% of the isolates obtained from diseased fruits belonged to the Fusarium lactis species complex (FLASC). F. oxysporum and F. proliferatum were also isolated but less frequently, 14% and 9% respectively. The pathogenicity of these Fusarium species was studied in assays using fruit as well as flower inoculation on different cultivars. Differences in pathogenicity were most clearly observed after fruit inoculation. These results however were not consistent with the results of flower inoculation, which is considered more representative, that showed only very little difference between the Fusarium species. Furthermore there was also an impact of the cultivar on the development of internal fruit rot. To gain a better insight in the latent phase of the infection process and particularly to study the development of the frequency of latent infections during the growing period of the fruit an experiment was set up and repeated three times over the course of the growing season. The presence of Fusarium in the flowers and in the fruits was determined at several time points between flowering and harvest using traditional surface disinfection and plating techniques using either natural infection or artificially inoculated (FLASC) flowers. The frequency of latently infected fruits stayed at a similar level from flower to harvest, indicating only very limited opportunities to affect the disease after initial infection took place. Preventing initial infection will thus be an important factor in the control of internal fruit rot. One way to reduce the amount of initial infections may be the removal of withering tissues such as pistil and petals, as preliminary results have shown that these were frequently saprophytically colonized with FLASC isolates. Several experiments indicated however that such removal was not successful, suggesting that the infection process is quite fast and that the number of airborne spores is insufficiently lowered by the removal of withering flowering structures. As our study to gain more insights into this pathosystem goes on, opportunities for sustainable control of internal fruit rot, such as prevention of flower infection by biological control agents, and screening for disease resistance, are being explored.status: publishe

Naar een meer uniforme tomatenkwaliteit tijdens het volledige seizoen

status: publishe

Redefining the target early during treatment. Can we visualize regional differences within the target volume using sequential diffusion weighted MRI?

PURPOSE: In head and neck cancer, diffusion weighted MRI (DWI) can predict response early during treatment. Treatment-induced changes and DWI-specific artifacts hinder an accurate registration between apparent diffusion coefficient (ADC) maps. The aim of the study was to develop a registration tool which calculates and visualizes regional changes in ADC. METHODS: Twenty patients with stage IV HNC treated with primary radiotherapy received an MRI including DWI before and early during treatment. Markers were manually placed at anatomical landmarks on the different modalities at both time points. A registration method, consisting of a fully automatic rigid and nonrigid registration and two semi-automatic thin-plate spline (TPS) warps was developed and applied to the image sets. After each registration step the mean registration errors were calculated and ΔADC was compared between good and poor responders. RESULTS: Adding the TPS warps significantly reduced the registration error (in mm, 6.3 ± 6.2 vs 3.2 ± 3.3 mm, p<0.001). After the marker based registration the median ΔADC in poor responders was significantly lower than in good responders (7% vs. 21%; p<0.001). CONCLUSIONS: This registration method allowed for a significant reduction of the mean registration error. Furthermore the voxel-wise calculation of the ΔADC early during radiotherapy allowed for a visualization of the regional differences of ΔADC within the tumor.Lambrecht M., Van Herck H., De Keyzer F., Vandecaveye V., Slagmolen P., Suetens P., Hermans R., Nuyts S., ''Redefining the target early during treatment. Can we visualize regional differences within the target volume using sequential diffusion weighted MRI?'', Radiotherapy and oncology, vol. 110, no. 2, pp. 329-334, February 2014.status: publishe

Quantification of diffusion-weighted MRI for treatment response assessment in head and neck cancer

Van Herck H., Vandecaveye V., Nuyts S., Lambrecht M., Hermans R., De Keyzer F., Suetens P., Slagmolen P., ''Quantification of diffusion-weighted MRI for treatment response assessment in head and neck cancer'', 11th biennial ESTRO meeting on physics and radiation technology for clinical radiotherapy, May 8-12, 2011, London, United Kingdom.status: publishe

Probabilistic urban inundation nowcasting

status: publishe

Visualizing treatment resistant regions within the tumor using sequential DWI: clinical validation

Van Herck H., Lambrecht M., Vandecaveye V., De Keyzer F., Slagmolen P., Suetens P., Hermans R., Nuyts S., ''Visualizing treatment resistant regions within the tumor using sequential DWI: clinical validation'', Radiotherapy and oncology, vol. 103 supplement 1, pp. S73-S74, 2012 (European Society for Radiotherapy & Oncology - ESTRO 31, May 9-13, 2012, Barcelona, Spain).status: publishe