COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

In vitro pre-exposure of Haemonchus contortus

International audienceDifferent authors have reported that eosinophils are capable of immobilising infective larvae of different species of nematodes in vitro. However, classifying larvae as mobile or immobile is so subjective that it does not always mean all apparently immobile larvae are dead or those that are mobile are capable of surviving further immune responses if administered to their natural hosts. The objective of this experimental study was therefore to substantiate the role of eosinophils in the killing of Haemonchus contortus infective larvae by comparing the infectivity in sheep of larvae that had been incubated with eosinophil-enriched cell suspensions with control larvae. Since it was not possible to isolate pure eosinophils from sheep blood, we were compelled to evaluate the effects of other blood cells contaminating our eosinophil-enriched suspensions. Although eosinophils and neutrophils were the only cells found adherent to H. contortus infective larvae in vitro, induced eosinophils in the presence of immune serum were primarily responsible for the drastic reduction in larval motility compared to the minor effects of neutrophils and mononuclear cells. Corresponding reductions in faecal egg count and worm numbers were observed when the incubated larvae were transferred intra-abomasally to sheep. Interestingly, the proportion of larvae that failed to establish was much higher following incubation with induced eosinophils compared with other cells or with immune serum alone. Although this study did not address the in vivo role of eosinophils in sheep, the results strongly indicate that sheep blood eosinophils have a larval killing potential in vitro, and a larval mobility test alone may not fully explain the level of damage inflicted on the larvae

Évolutions épidémiologiques et nouvelles contraintes dans la lutte contre les myiases ovines

Sheep myiasis : recent developments in epidemiology and novel constraints in control. The blowfly (Lucilia sericata), the fleshfly (Wohlfahrtia magnifica) and the nasal-bot fly (Oestrus ovis) are important pests for the sheep industry. Moreover, sporadic opthalmomyiasis cases due to O. ovis are reported in human beings worldwide. In the last 20 years, the epidemiology of ovine myiasis showed considerable evolution in France with a marked spreading of their geographical distribution. A large array of chemical compounds is still available to control these parasites in meat sheep. However, due to revised milk withdrawal times, many efficient chemical compounds are now forbidden in dairy sheep. In the same time, alternative methods to chemical treatments are still in their infancy. Therefore, the information towards sheep breeders and veterinarians is of critical importance to detect clinical cases as soon as possible and for the global survey of these parasitosis.Une myiase naso-sinusale à Oestrus ovis et deux myiases cutanées à Lucilia sericata et Wohlfahrtia magnifica constituent toujours une dominante pathologique des ovins au pâturage. De plus, la myiase naso-sinusale à Oestrus ovis est responsable de cas sporadiques d’ophtalmomyiase externe chez l’homme. Dans les dernières décennies, ces affections parasitaires ont connu des évolutions épidémiologiques importantes, gagnant de nouveaux territoires en France métropolitaine. Leur contrôle reste tout à fait réalisable en élevage ovin allaitant même s’il est contraignant, mais il s’est considérablement compliqué en élevage ovin laitier en raison d’interdictions réglementaires de l’utilisation de nombreuses molécules actives. En parallèle, les méthodes alternatives au traitement chimique restent très limitées. L’information des éleveurs et des vétérinaires est donc essentielle pour la détection précoce des cas et la surveillance de ces parasitoses.Jacquiet Philippe, Alzieu Jean-Pierre, Liénard Emmanuel, Grisez Chistelle, Prévot Françoise, Bergeaud Jean-Paul, Bouhsira Emilie, Franc Michel, Dorchies Philippe. Évolutions épidémiologiques et nouvelles contraintes dans la lutte contre les myiases ovines. In: Bulletin de l'Académie Vétérinaire de France tome 169 n°1, 2016. pp. 46-53

In vitro pre-exposure of Haemonchus contortus L3 to blood eosinophils reduces their establishment potential in sheep

Different authors have reported that eosinophils are capable of immobilising infective larvae of different species of nematodes in vitro. However, classifying larvae as mobile or immobile is so subjective that it does not always mean all apparently immobile larvae are dead or those that are mobile are capable of surviving further immune responses if administered to their natural hosts. The objective of this experimental study was therefore to substantiate the role of eosinophils in the killing of Haemonchus contortus infective larvae by comparing the infectivity in sheep of larvae that had been incubated with eosinophil-enriched cell suspensions with control larvae. Since it was not possible to isolate pure eosinophils from sheep blood, we were compelled to evaluate the effects of other blood cells contaminating our eosinophil-enriched suspensions. Although eosinophils and neutrophils were the only cells found adherent to H. contortus infective larvae in vitro, induced eosinophils in the presence of immune serum were primarily responsible for the drastic reduction in larval motility compared to the minor effects of neutrophils and mononuclear cells. Corresponding reductions in faecal egg count and worm numbers were observed when the incubated larvae were transferred intra-abomasally to sheep. Interestingly, the proportion of larvae that failed to establish was much higher following incubation with induced eosinophils compared with other cells or with immune serum alone. Although this study did not address the in vivo role of eosinophils in sheep, the results strongly indicate that sheep blood eosinophils have a larval killing potential in vitro, and a larval mobility test alone may not fully explain the level of damage inflicted on the larvae

On the potential of Resonant Ultrasound Spectroscopy applied to the non-destructive characterization of the density of (LPBF) additively manufactured materials

International audienceThe objective of the present work is to investigate the potential of Resonant Ultrasound Spectroscopy (RUS) as an innovative technique for the nondestructive analysis of Laser Powder Bed Fusion (LPBF) $AlSi_7Mg_{0.6}$ parts. The acoustic resonance measurements are tested against an experimental database that covers a broad range of process parameters and large variations of the standard volumetric energy density. Two other nondestructive techniques are used to assess the potential of the RUS measurements of additively manufactured samples: the easy-to-use Archimedes density measurement and the cost-intensive computerized X-ray tomography. Our results show that RUS provides both qualitative and quantitative insights that allow the detection of the amount of lack of fusion porosities and the estimation of the elastic properties of the fabricated samples. Quantitative correlations between the three nondestructive testing methods are obtained, hinting at how RUS could be used effectively for systematic post-production testing of LPBF samples

Haemonchus contortus (Nematoda : Trichostrongylidae) infection in lambs elicits an unequivocal Th2 immune response

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Cellular and humoral local immune responses in sheep experimentally infected with Oestrus ovis (Diptera: Oestridae)

International audienceCellular and humoral local responses were investigated following repetitive artificial Oestrus ovis infections in lambs. The presence of larvae induced a huge local recruitment of either leucocytes (T and B lymphocytes, macrophages) or granulocytes (eosinophils, mast cells and globule leucocytes). This cellular response was more pronounced in the ethmoid and sinus (development sites of second and third instar larvae) than in the septum or turbinates where first instar larvae migrate. Infected lambs produced Oestrus ovis specific IgG and IgA antibodies in their mucus. This local humoral response was mainly directed against larval salivary gland antigens and not against larval digestive tract antigens. Compared to the control animals, the sinusal mucosa of infected animals was extremely thickened and the epithelium exhibited hyperplasia, metaplasia and eosinophilic exocytosis. The possible roles of these local immune responses in the regulation of O. ovis larvae populations in sheep are discussed

Regulation of Oestrus ovis (Diptera: Oestridae)populations in previously exposed and naïve sheep

Larvae of Oestrus ovis (Insecta: Diptera: Oestridae) are common parasites of nasal and sinus cavities of sheep and goats. During larval development, a specific immune reaction is initiated by the host with a humoral local and systemic response and the recruitment of eosinophils and mast cells in the upper airways mucosae. Nevertheless, the roles of these responses in the regulation of O. ovis larvae populations in sheep are not yet known. The aim of this study was to compare the establishment and the development of larvae as well as some inflammatory or immune parameters between different groups of half-sibling sheep:(i) a primed group experimentally infected twice before a challenge infection, (ii and iii) two groups infected once only and previously treated with a long-lasting corticoïd before the challenge (one group) or not (the other group). A fourth group of noninfected animals was added in the experimental design. The larval establishment rate was 23% in the corticoïd treated group compared to about 10% in the two other infected groups. Moreover, the larval development appeared more rapid in the corticoïd treated group than in the two other infected groups suggesting that the inflammatory response is involved in the regulation of O. ovis populations. By contrast, no differences in the establishment rates were shown in the primed group compared to the naïve group (without corticoïd treatment) despite evidence of higher eosinophilia, serum specific IgG, and immediate hypersensibility to excretory–secretory products of larvae. The specific lymphocyte proliferation was reduced in the primed group compared to the naïve one suggesting that an immuno-suppression occurs following repetitive O. ovis infections

Functional investigation of a QTL affecting resistance to Haemonchus contortus in sheep

This study reports a functional characterization of a limited segment (QTL) of sheep chromosome 12 associated with resistance to the abomasal nematode Haemonchus contortus. The first objective was to validate the identified QTL through the comparison of genetically susceptible (N) and resistant (R) sheep produced from Martinik × Romane back-cross sheep. The R and N genotype groups were then experimentally infected with 10 000 H. contortus larvae and measured for FEC (every three days from 18 to 30 days post-challenge), haematocrit, worm burden and fertility. Significant differences in FEC and haematocrit drop were found between R and N sheep. In addition, the female worms recovered from R sheep were less fecund. The second step of the characterization was to investigate functional mechanisms associated with the QTL, thanks to a gene expression analysis performed on the abomasal mucosa and the abomasal lymph node. The gene expression level of a candidate gene lying within the QTL region (PAPP-A2) was measured. In addition, putative interactions between the chromosome segment under study and the top ten differentially expressed genes between resistant MBB and susceptible RMN sheep highlighted in a previous microarray experiment were investigated. We found an induction of Th-2 related cytokine genes expression in the abomasal mucosa of R sheep. Down-regulation of the PAPP-A2 gene expression was observed between naïve and challenged sheep although no differential expression was recorded between challenged R and N sheep. The genotyping of this limited region should contribute to the ability to predict the intrinsic resistance level of sheep