BackgroundAcute flaccid paralysis (AFP) is characterized by rapidly progressive limb weakness with low muscle tone. It has a broad differential diagnosis, which includes acute flaccid myelitis (AFM... Show moreBackgroundAcute flaccid paralysis (AFP) is characterized by rapidly progressive limb weakness with low muscle tone. It has a broad differential diagnosis, which includes acute flaccid myelitis (AFM), a rare polio-like condition that mainly affects young children. Differentiation between AFM and other causes of AFP may be difficult, particularly at onset of disease. Here, we evaluate the diagnostic criteria for AFM and compare AFM to other causes of acute weakness in children, aiming to identify differentiating clinical and diagnostic features.MethodsThe diagnostic criteria for AFM were applied to a cohort of children with acute onset of limb weakness. An initial classification based on positive diagnostic criteria was compared to the final classification, based on application of features suggestive for an alternative diagnosis and discussion with expert neurologists. Cases classified as definite, probable, or possible AFM or uncertain, were compared to cases with an alternative diagnosis.ResultsOf 141 patients, seven out of nine patients initially classified as definite AFM, retained this label after further classification. For probable AFM, this was 3/11, for possible AFM 3/14 and for uncertain 11/43. Patients initially classified as probable or possible AFM were most commonly diagnosed with transverse myelitis (16/25). If the initial classification was uncertain, Guillain-Barré syndrome was the most common diagnosis (31/43). Clinical and diagnostic features not included in the diagnostic criteria, were often used for the final classification.ConclusionThe current diagnostic criteria for AFM usually perform well, but additional features are sometimes required to distinguish AFM from other conditions. Show less
Background: Acute flaccid myelitis (AFM) is a polio-like condition affecting mainly children and involving the central nervous system (CNS). AFM has been associated with different non-polio... Show moreBackground: Acute flaccid myelitis (AFM) is a polio-like condition affecting mainly children and involving the central nervous system (CNS). AFM has been associated with different non-polio-enteroviruses (EVs), in particular EV- D68 and EV-A71. Reliable incidence rates in European countries are not available. Aim: To report AFM incidence in children in the Netherlands and its occurrence relative to EV-D68 and EV-A71 detections. Methods: In 10 Dutch hospitals, we reviewed electronic health records of patients diagnosed with a clinical syndrome including limb weakness and/or CNS infection and who were < 18 years old when symptoms started. After excluding those with a clear alternative diagnosis to AFM, those without weakness, and removing duplicate records, only patients diagnosed in January 2014- December 2019 were retained and further classified according to current diagnostic criteria. Incidence rates were based on definite and probable AFM cases. Cases' occurrences during the study period were co-examined with laboratory-surveillance detections of EV- D68 and EV-A71. Results: Among 143 patients included, eight were classified as definite and three as probable AFM. AFM mean incidence rate was 0.06/100,000 children/year (95% CI: -0.03 to 0.14). All patient samples were negative for EV-A71. Of respiratory samples in seven patients, five were EV- D68 positive. AFM cases clustered in periods with increased EV-D68 and EV-A71 detections. Conclusions: AFM is rare in children in the Netherlands. The temporal coincidence of EV- D68 circulation and AFM and the detection of this virus in several cases' samples support its association with AFM. Increased AFM awareness among clinicians, adequate diagnostics and case registration matter to monitor the incidence. Show less
Background: Countries worldwide are focusing to mitigate the ongoing SARS-CoV-2 pandemic by employing public health measures. Laboratories have a key role in the control of SARS- CoV-2 transmission... Show moreBackground: Countries worldwide are focusing to mitigate the ongoing SARS-CoV-2 pandemic by employing public health measures. Laboratories have a key role in the control of SARS- CoV-2 transmission. Serology for SARS-CoV-2 is of critical importance to support diagnosis, define the epidemiological framework and evaluate immune responses to natural infection and vaccine administration. Aim: The aim of this study was the assessment of the actual capability among laboratories involved in sero-epidemiological studies on COVID-19 in EU/EEA and EU enlargement countries to detect SARS-CoV-2 antibodies through an external quality assessment ( EQA) based on proficiency testing. Methods: The EQA panels were composed of eight different, pooled human serum samples (all collected in 2020 before the vaccine roll-out), addressing sensitivity and specificity of detection. The panels and two EU human SARS- CoV-2 serological standards were sent to 56 laboratories in 30 countries. Results: The overall performance of laboratories within this EQA indicated a robust ability to establish past SARS-CoV-2 infections via detection of anti-SARS- CoV-2 antibodies, with 53 of 55 laboratories using at least one test that characterised all EQA samples correctly. IgM-specific test methods provided most incorrect sample characterisations (24/208), while test methods detecting total immunoglobulin (0/119) and neutralising antibodies (2/230) performed the best. The semiquantitative assays used by the EQA participants also showed a robust performance in relation to the standards. Conclusion: Our EQA showed a high capability across European reference laboratories for reliable diagnostics for SARS-CoV-2 antibody responses. Serological tests that provide robust and reliable detection of anti SARS- CoV-2 antibodies are available. Show less
Reusken, C.B.; Buiting, A.; Bleeker-Rovers, C.; Diederen, B.; Hooiveld, M.; Friesema, I.; ... ; Kluytmans, J. 2020
To rapidly assess possible community transmission in Noord-Brabant, the Netherlands, healthcare workers (HCW) with mild respiratory complaints and without epidemiological link (contact with... Show moreTo rapidly assess possible community transmission in Noord-Brabant, the Netherlands, healthcare workers (HCW) with mild respiratory complaints and without epidemiological link (contact with confirmed case or visited areas with active circulation) were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Within 2 days, 1,097 HCW in nine hospitals were tested; 45 (4.1%) were positive. Of six hospitals with positive HCW, two accounted for 38 positive HCW. The results informed local and national risk management. Show less
Lelieveld, L.T.; Mirzaian, M.; Kuo, C.L.; Artola Perez de Azanza, M.E.; Guimaraes Da Lomba Ferraz, M.J.; Peter, R.E.A.; ... ; Aerts, J.M.F.G. 2019
β-glucosidases (GBA1 [glucocerebrosidase], GBA2, and GBA3) are ubiquitous, essential enzymes. Lysosomal GBA1 and cytosol-facing GBA2 degrade glucosylceramide (GlcCer); GBA1 deficiency causes... Show moreβ-glucosidases (GBA1 [glucocerebrosidase], GBA2, and GBA3) are ubiquitous, essential enzymes. Lysosomal GBA1 and cytosol-facing GBA2 degrade glucosylceramide (GlcCer); GBA1 deficiency causes Gaucher disease (GD), a lysosomal storage disorder characterized by lysosomal accumulation of GlcCer, which is partly converted to glucosylsphingosine (GlcSph). GBA1 and GBA2 also may transfer glucose from GlcCer to cholesterol, yielding glucosylated cholesterol (GlcChol). Here, we aimed to clarify the role of zebrafish Gba2 in glycosphingolipid metabolism during Gba1 deficiency in zebrafish (Danio rerio), which are able to survive total Gba1 deficiency. We developed Gba1 and Gba2 zebrafish knockouts (gba1-/- and gba2-/-, respectively) using CRISPR/Cas9, modulated glucosidases genetically and pharmacologically, studied GlcCer metabolism in individual larvae, and explored the feasibility of pharmacologic or genetic interventions. Activity-based probes and quantification of relevant glycolipid metabolites confirmed enzyme deficiency. GlcSph increased in gba1-/- larvae (0.09 pmol/fish) but did not increase more in gba1-/-:gba2-/- larvae. GlcCer was comparable in gba1-/- and wild-type (WT) larvae but increased in gba2-/- and gba1-/-:gba2-/- larvae. Independent of Gba1 status, GlcChol was low in all gba2-/- larvae (0.05 vs. 0.18. pmol/fish in WT). Pharmacologic inactivation of zebrafish Gba1 comparably increased GlcSph. Inhibition of glucosylceramide synthase in Gba1-deficient larvae reduced GlcCer and GlcSph, and concomitant inhibition of glucosylceramide synthase and Gba2 with iminosugars also reduced excessive GlcChol. Finally, overexpression of human GBA1 and injection of recombinant GBA1 both decreased GlcSph. We determined that zebrafish larvae offer an attractive model to study glucosidase actions in glycosphingolipid metabolism in vivo, and we identified distinguishing characteristics of zebrafish Gba2 deficiency. Show less
Backer, J.A.; Wallinga, J.; Meijer, A.; Donker, G.A.; Hoek, W. van der; M. van boven 2019
Basic research in pattern formation is concerned with the generation of phenotypes and tissues. It can therefore lead to new tools for medical research. These include phenotypic screening assays,... Show moreBasic research in pattern formation is concerned with the generation of phenotypes and tissues. It can therefore lead to new tools for medical research. These include phenotypic screening assays, applications in tissue engineering, as well as general advances in biomedical knowledge. Our aim here is to discuss this emerging field with special reference to tools based on zebrafish developmental biology. We describe phenotypic screening assays being developed in our own and other labs. Our assays involve: (i) systemic or local administration of a test compound or drug to zebrafish in vivo; (ii) the subsequent detection or "readout" of a defined phenotypic change. A positive readout may result from binding of the test compound to a molecular target involved in a developmental pathway. We present preliminary data on assays for compounds that modulate skeletal patterning, bone turnover, immune responses, inflammation and early-life stress. The assays use live zebrafish embryos and larvae as well as adult fish undergoing caudal fin regeneration. We describe proof-of-concept studies on the localised targeting of compounds into regeneration blastemas using microcarriers. Zebrafish are cheaper to maintain than rodents, produce large numbers of transparent eggs, and some zebrafish assays could be scaled-up into medium and high throughput screens. However, advances in automation and imaging are required. Zebrafish cannot replace mammalian models in the drug development pipeline. Nevertheless, they can provide a cost-effective bridge between cell-based assays and mammalian whole-organism models. Show less
