Publications by authors named "Valentin Greigert"

Article Synopsis
  • Cryptosporidium parvum is a parasite that cannot produce ATP due to its reduced mitochondrion and relies exclusively on glycolysis for energy.
  • Despite the presence of potential glucose transporters and hexokinase, they are not critical for parasite growth, indicating an alternative method for obtaining necessary metabolic substrates.
  • The parasite utilizes glucose-6-phosphate directly from host cells and also extracts phosphorylated glucose from its own amylopectin reserves through glycogen phosphorylase.
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Cryptosporidiosis is a major cause of severe diarrheal disease in infants from resource poor settings. The majority of infections are caused by the human-specific pathogen and absence of in vitro growth platforms has limited our understanding of host-pathogen interactions and development of effective treatments. To address this problem, we developed a stem cell-derived culture system for using human enterocytes differentiated under air-liquid interface (ALI) conditions.

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Cryptosporidiosis is a major cause of severe diarrheal disease in infants from resource poor settings. The majority of infections are caused by the human-specific pathogen and absence of in vitro growth platforms has limited our understanding of host-pathogen interactions and development of effective treatments. To address this problem, we developed a stem cell-derived culture system for using human enterocytes differentiated under air-liquid interface (ALI) conditions.

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is an obligate intracellular parasite with a highly reduced mitochondrion that lacks the TCA cycle and the ability to generate ATP, making the parasite reliant on glycolysis. Genetic ablation experiments demonstrated that neither of the two putative glucose transporters CpGT1 and CpGT2 were essential for growth. Surprisingly, hexokinase was also dispensable for parasite growth while the downstream enzyme aldolase was required, suggesting the parasite has an alternative way of obtaining phosphorylated hexose.

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Introduction: The particularities of the ocular immune environment and its barrier protection in the context of infection are not well elucidated. The apicomplexan parasite is one of the pathogens successfully crossing this barrier and establishing chronic infection in retinal cells.

Methods: As a first approach, we studied the initial cytokine network in vitro in four human cell lines: Retinal pigmented epithelial (RPE), microglial, astrocytic and Müller cells.

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Background: Undernutrition and schistosomiasis are public health problems and often occur in low and middle-income countries. Protein undernutrition can alter the host-parasite environment system and aggravate the course of schistosomiasis. This study aimed to assess the impact of a low-protein diet on the efficacy of praziquantel.

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Background: One of the considerable challenges of schistosomiasis chemotherapy is the inefficacy of praziquantel (PZQ) at the initial phase of the infection. Immature schistosomes are not susceptible to PZQ at the curative dose. Here, we investigated the efficacy of different PZQ regimens administered during the initial stage of Schistosoma mansoni infection in mice.

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Interactions between the prokaryotic microbiome and eukaryotic parasites in the vertebrate gut may affect overall host health and disease. While intertropical areas exhibit a high rate of parasites carriers, such interactions are understudied in these populations. Our objectives were to (1) describe the gut microbiome of individuals living in Madagascar, (2) identify potential associations between bacterial taxa and parasites colonizing the digestive tract and (3) highlight main determinants of the gut microbiota composition in this developing country.

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Cases of pneumonia (PCP) in patients suffering from COVID-19 were described in patients with various comorbidities and outcomes. The diagnosis of PCP in these patients is difficult due to clinical and radiological similarities. We carried out this study in order to better describe potentially at-risk patients and their outcomes.

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Infections with the protozoan parasite Toxoplasma gondii are frequent, but one of its main consequences, ocular toxoplasmosis (OT), remains poorly understood. While its clinical description has recently attracted more attention and publications, the underlying pathophysiological mechanisms are only sparsely elucidated, which is partly due to the inherent difficulties to establish relevant animal models. Furthermore, the particularities of the ocular environment explain why the abundant knowledge on systemic toxoplasmosis cannot be just transferred to the ocular situation.

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We developed a score, with easily accessible data (age, sex, body mass index, dyspnea, inflammatory parameters), to predict the risk of rapid progression to severe coronavirus disease 2019. Using a cutoff of >6 points, the negative predictive value was 87%.

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BackgroundIn March 2020, the COVID-19 outbreak was declared a pandemic by the World Health Organization.AimOur objective was to identify risk factors predictive of severe disease and death in France.MethodsIn this prospective cohort study, we included patients ≥ 18 years old with confirmed COVID-19, hospitalised in Strasbourg and Mulhouse hospitals (France), in March 2020.

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Objective: The main objective of this study was to investigate the prognostic value of early systematic chest computed tomography (CT) with quantification of lung lesions in coronavirus disease 2019 (COVID-19) patients.

Methods: We studied 572 patients diagnosed with COVID-19 (confirmed using polymerase chain reaction) for whom a chest CT was performed at hospital admission. Visual quantification was used to classify patients as per the percentage of lung parenchyma affected by COVID-19 lesions: normal CT, 0-10%, 11-25%, 26-50%, 51-75% and >75%.

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Diphyllobothriasis is a parasitic fish-borne disease caused by tapeworms of the genus Dibothriocephalus (=Diphyllobothrium). The majority of reported cases are attributed to D. latum, based on morphological identification of eggs or proglottids.

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Fleas are ectoparasites of various animals, including Homo sapiens Linnaeus, 1758 (Primates: Hominidae). Among the species relevant to the human health field, either due to their dermatopathological potential or because of their role as vectors of microorganisms responsible for infectious diseases, such as plague or murine typhus, are the human flea, oriental rat flea, closely related cat and dog fleas, and chigoe flea. However, other species can accidentally infest humans.

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Ocular toxoplasmosis (OT), i.e., the ocular manifestation of infection, is one of the leading causes of posterior uveitis.

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During the 2017-2018 flu epidemic, the point-of-care Alere-i (n = 72) and reverse transcription polymerase chain reaction (n = 106) tests were compared. Patients in the point-of-care group were administered oseltamivir significantly more rapidly (9 hours vs 23 hours), they spent less time in the emergency department, and they had lower rates of antibiotic administration and hospitalization.

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Toxoplasmosis is a common infection whose worldwide prevalence is estimated at 30%, with large disparities across the world. Among infected subjects, the prevalence of ocular toxoplasmosis (OT) is, however, limited to about 2% in Europe and 17% in South America. In France, it is estimated that about 1 000 000 patients present either active OT or subsequent chorioretinal scars.

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Background: Several cases of infections due to Echinococcus multilocularis, Taenia martis and Taenia crassiceps were recently described in various species of captive non-human primates (NHPs) harbored in the Strasbourg Primate Center (SPC). Furthermore, one of the first cases of human cysticercosis due to T. martis was described in the Strasbourg region.

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Article Synopsis
  • Ocular toxoplasmosis (OT) is primarily due to Toxoplasma gondii infection, with retinochoroiditis being a major complication.
  • There is a significant variability in the disease's pathophysiology based on the specific strains of Toxoplasma, highlighted by the influence of the virulence factor ROP16.
  • Our study using different Toxoplasma strains in a mouse model revealed strain-specific immune responses and retinal pathology, furthering the understanding of OT's complex interactions with the host's immune system.
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Introduction: Intestinal parasitic infections are a major public health problem in inter-tropical areas. The aim of our study was to describe the situation in Mahajanga, Madagascar with a particular focus on two protozoa, Dientamoeba fragilis and Blastocystis sp.

Methods: This was a prospective study from February to June 2015.

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Microsporidia cause opportunistic infections in highly immunodeficient individuals. Few studies on the epidemiology of these infections have been conducted in France. Between 2014 and 2016, we undertook a study to estimate the prevalence and circulating genotypes of this fungus-related micro-organism among the population of Strasbourg University Hospital.

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