Ethnic differences in COVID-19 deaths across various waves of Coronavirus pandemic in Netherlands

Background

It is not known how ethnic differences in COVID-19 deaths in the Netherlands evolved throughout the pandemic, especially after introduction of ethnicity-oriented COVID-19 prevention measures. We investigated associations between ethnicity and COVID-19 deaths across first wave of the pandemic, inter-wave period, and second wave in the Netherlands.

Methods

We obtained multiple registry data from Statistics Netherlands spanning from 01 March 2020 to 14 March 2021 comprising of 17.4 million inhabitants. We estimated incidence rate ratios (IRRs) for COVID-19 deaths among ethnic groups using Poisson regression models and adjusted for relevant socio-demographic factors. We used similar models to estimate IRRs for non-COVID-19 deaths among ethnic groups.

Results

Ethnic minority populations exhibited higher risk of COVID-19 deaths than the Dutch origin population throughout various study periods. The most elevated risk of COVID-19 deaths was in populations originating from low- and middle-income countries, especially those with Turkish, Moroccan, and Surinamese background. The elevated risk of COVID-19 deaths among ethnic minority groups (as compared to Dutch origin population) was higher in inter-wave period (4 times higher) and second wave (2 times higher) when compared to the first wave (1.5 times as higher). Ethnic differences in COVID-19 deaths were larger compared to non-COVID-19 deaths.

Conclusions

Ethnic differences in COVID-19 deaths persisted across first wave, inter-wave period and second wave in the Netherlands despite introduction of ethnicity-oriented prevention measures. Research on explanatory mechanisms and novel prevention measures are needed to address the ongoing differences in COVID-19 deaths across ethnic groups.

Key messages

• Ethnic differences in COVID-19 deaths persisted in the Netherlands despite introduction of ethnicity-oriented prevention measures.We therefore call for better prevention measures.

• Well known drivers of SARS-CoV-2 infection such as household wealth, did not explain our findings calling for an in-depth understanding of drivers of ethnic differences in COVID-19 deaths.

Restoration of impaired intestinal barrier function by the hydrolysed casein diet contributes to the prevention of type 1 diabetes in the diabetes-prone BioBreeding rat

AIMS/HYPOTHESIS

Impaired intestinal barrier function is observed in type 1 diabetes patients and animal models of the disease. Exposure to diabetogenic antigens from the intestinal milieu due to a compromised intestinal barrier is considered essential for induction of the autoimmune process leading to type 1 diabetes. Since a hydrolysed casein (HC) diet prevents autoimmune diabetes onset in diabetes-prone (DP)-BioBreeding (BB) rats, we studied the role of the HC diet on intestinal barrier function and, therefore, prevention of autoimmune diabetes onset in this animal model.

METHODS

DP-BB rats were fed the HC diet from weaning onwards and monitored for autoimmune diabetes development. Intestinal permeability was assessed in vivo by lactulose-mannitol test and ex vivo by measuring transepithelial electrical resistance (TEER). Levels of serum zonulin, a physiological tight junction modulator, were measured by ELISA. Ileal mRNA expression of Myo9b, Cldn1, Cldn2 and Ocln (which encode the tight junction-related proteins myosin IXb, claudin-1, claudin-2 and occludin) and Il-10, Tgf-ß (also known as Il10 and Tgfb, respectively, which encode regulatory cytokines) was analysed by quantitative PCR.

RESULTS

The HC diet reduced autoimmune diabetes by 50% in DP-BB rats. In DP-BB rats, prediabetic gut permeability negatively correlated with the moment of autoimmune diabetes onset. The improved intestinal barrier function that was induced by HC diet in DP-BB rats was visualised by decreasing lactulose:mannitol ratio, decreasing serum zonulin levels and increasing ileal TEER. The HC diet modified ileal mRNA expression of Myo9b, and Cldn1 and Cldn2, but left Ocln expression unaltered.

CONCLUSIONS/INTERPRETATION

Improved intestinal barrier function might be an important intermediate in the prevention of autoimmune diabetes by the HC diet in DP-BB rats. Effects on tight junctions, ileal cytokines and zonulin production might be important mechanisms for this effect.

The relationship between impaired decision-making, sensation seeking and readiness to change in cigarette smokers

OBJECTIVE

The study investigated whether impaired decision-making as measured by the Gambling Task and Sensation Seeking, on one hand, and nicotine-dependence and readiness to change, on the other hand, show mutual influences in cigarette smokers.

METHODS

Cigarette smokers were classified as dependent or non-dependent smokers. Assessment included stages of change (RCQ), decisional balance (DBS), Sensation Seeking Scale Form-V (SSS-V), and performance on the Gambling Task (GT).

RESULTS

With the exception of a significant higher score in the SSS-V subscale Experience Seeking in dependent smokers, correlations between nicotine-dependence and cognitive features were not significant. The directions of the non-significant differences were not consistent. No significant relationship was found between the SSS-V and the GT, on one hand, and the readiness to change smoking behaviour, on the other hand.

CONCLUSIONS

The results of the present study suggest that impaired performance on the GT and high scores in Sensation Seeking do not play an important role in nicotine-dependence and readiness to change smoking behaviour or vice versa.

Comparison of the faecal microflora of patients with ankylosing spondylitis and controls using molecular methods of analysis

OBJECTIVES

To determine whether differences within the complex intestinal microflora can be demonstrated between patients with ankylosing spondylitis (AS) and healthy individuals.

METHODS

The composition of the faecal microflora of 15 ankylosing spondylitis patients and 15 matched controls was determined using a variety of nucleic acid-based methods, including denaturing gradient gel electrophoresis (DGGE). Concentrations of serum antibodies reactive with intestinal bacteria were determined. T-cell proliferation responses to autologous intestinal bacteria were determined using a bioluminescent assay.

RESULTS

DGGE demonstrated a unique and stable bacterial community in the faeces of each individual. No specific differences in colonization profiles were discernible between patients and controls. Analysis of individual bacterial groups using nucleic acid-based methods showed no differences in faecal colonization with Klebsiella pneumoniae or Bacteroides vulgatus. A significantly higher proportion of faecal samples from AS patients were found to contain sulphate-reducing bacteria compared with samples from controls (P=0.0004). Three out of five patients showed elevated T-cell proliferation responses to Bacteroides species cultured from their own faeces. The concentrations of serum immunoglobulin A (IgA) and IgM antibodies reactive with klebsiella or bacteroides cells were lower in the patient group relative to the controls.

CONCLUSIONS

By using DGGE, we have demonstrated the complexity and individuality of the human intestinal microflora and shown that this is a confounding factor in determining the possible significance of individual organisms in the pathogenesis of spondyloarthritis. Nevertheless, we demonstrated a higher prevalence of sulphate-reducing bacteria in the faeces of patients with AS. These organisms have been implicated in the pathogenesis of inflammatory bowel disease. We also detected a possible loss of immunological tolerance to autologous Bacteroides isolates in patients with AS.

Dehalobacter restrictus gen. nov. and sp. nov., a strictly anaerobic bacterium that reductively dechlorinates tetra- and trichloroethene in an anaerobic respiration

The highly enriched anaerobic bacterium that couples the reductive dechlorination of tetrachloroethene to growth, previously referred to as PER-K23, was obtained in pure culture and characterized. The bacterium, which does not form spores, is a small, gram-negative rod with one lateral flagellum. It utilized only H2 as an electron donor and tetrachloroethene and trichloroethene as electron acceptors in an anaerobic respiration process; it could not grow fermentatively. Acetate served as a carbon source in a defined medium containing iron as the sole trace element, the two vitamins thiamine and cyanocobalamin, and the three amino acids arginine, histidine, and threonine. The cells contained menaquinones and b-type cytochromes. The G+C content of the DNA was 45.3 +/- 0.3 mol%. The cell wall consisted of type-A3gamma peptidoglycan with ll-diaminopimelic acid and one glycine as an interpeptide bridge. The cells are surrounded by an S-layer; an outer membrane was absent. Comparative sequence analysis of the 16S rRNA sequence showed that PER-K23 is related to gram-positive bacteria with a low G+C content of the DNA. Based on the cytological, physiological, and phylogenetic characterization, it is proposed to affiliate the isolate to a new genus, Dehalobacter, with PER-K23 as the type strain of the new species Dehalobacter restrictus.

Group-Specific 16S rRNA-Targeted Oligonucleotide Probes To Identify Thermophilic Bacteria in Marine Hydrothermal Vents

Four 16S rRNA-targeted oligonucleotide probes were designed for the detection of thermophilic members of the domain Bacteria known to thrive in marine hydrothermal systems. We developed and characterized probes encompassing most of the thermophilic members of the genus Bacillus, most species of the genus Thermus, the genera Thermotoga and Thermosipho, and the Aquificales order. The temperature of dissociation of each probe was determined. Probe specificities to the target groups were demonstrated by whole-cell and dot blot hybridization against a collection of target and nontarget rRNAs. Whole-cell hybridizations with the specific probes were performed on cells extracted from hydrothermal vent chimneys. One of the samples contained cells that hybridized to the probe specific to genera Thermotoga and Thermosipho. No positive signals could be detected in the samples tested with the probes whose specificities encompassed either the genus Thermus or the thermophilic members of the genus Bacillus. However, when simultaneous hybridizations with the probe specific to the order Aquificales and a probe specific to the domain Bacteria (R. I. Amann, B. Binder, R. J. Olson, S. W. Chisholm, R. Devereux, and D. A. Stahl, Appl. Environ. Microbiol. 56:1919-1925, 1990) were performed on cells extracted from the top and exterior subsamples of chimneys, positive signals were obtained from morphologically diverse bacteria representing about 40% of the bacterial population. Since specificity studies also revealed that the bacterial probe did not hybridize with the members of the order Aquificales, the detected cells may therefore correspond to a new type of bacteria. One of the observed morphotypes was similar to that of a strictly anaerobic autotrophic sulfur-reducing strain that we isolated from the chimney samples. This work demonstrates that application of whole-cell hybridization with probes specific for different phylogenetic levels is a useful tool for detailed studies of hydrothermal vent microbial ecology.

Distribution of microorganisms in deep-sea hydrothermal vent chimneys investigated by whole-cell hybridization and enrichment culture of thermophilic subpopulations

The microbial community structure of hydrothermal vent chimneys was evaluated by the combined use of enrichment cultures and whole-cell hybridizations with fluorescently labeled 16S rRNA-based oligonucleotide probes. Chimneys were collected during the Microsmoke cruise on the Mid-Atlantic Ridge and were subsampled on board and stored under reduced conditions or fixed. For estimation of culturable thermophiles, selective media were inoculated by dilution series of the samples and incubated at 65, 80, and 95(deg)C. To analyze the microbial diversity of the samples, cells were extracted from the fixed chimney structure samples and hybridized with domain- and kingdom-specific probes. Quantification of the extracted cells was assessed by whole-cell hybridization on membrane filters. By both methods, the largest amounts of microorganisms were found in the upper and outer parts of the chimneys, although even the inner parts contained culturable and detectable amounts of cells. Different morphotypes of thermophilic and hyperthermophilic microorganisms were enriched and detected in samples. Our data clearly indicate that the morphological diversity observed by using whole-cell hybridization is much larger than that assessed by use of culture-based enrichments. This new approach, including culture-independent and -dependent methods to study hydrothermal vent chimneys, showed an uneven distribution of a diverse microbial community. Application of lower-level specific probes for known families and genera within each domain by our approach will be useful to reveal the real extent and nature of the chimney microbial diversity and to support cultivation attempts.

Characterization of the pea ENOD12B gene and expression analyses of the two ENOD12 genes in nodule, stem and flower tissue

The ENOD12 gene family in pea consists of two different members. The cDNA clone, pPsENOD12, represents the PsENOD12A gene. The second ENOD12 gene, PsENOD12B, was selected from a genomic library using pPsENOD12 as a probe and this gene was sequenced and characterized. The coding regions of the two genes are strikingly similar. Both encode proteins having a signal peptide sequence and a region with pentapeptide units rich in prolines. ENOD12A has a series of rather conserved repeating pentapeptide units, whereas in ENOD12B the number of pentapeptide units is less and these are less conserved. From the amino acid sequence it is obvious that the PsENOD12 genes encode proline-rich proteins which are closely related to proteins that have been identified as components of soybean cell walls (SbPRPs). Previously, Northern blot analyses had shown that ENOD12 genes are expressed in a tissue-specific manner. A high expression level is found in Rhizobium-infected roots and in nodules, whereas expression in flower and stem is lower. This raised the question of which gene is expressed where and when. The availability of the sequences of both ENOD12 genes allowed us to analyse the expression of the two genes separately. Specific oligonucleotides were used to copy the ENOD12 mRNAs and to amplify the cDNAs in a polymerase chain reaction. It was demonstrated that in all the tissues containing ENOD12 mRNA, both genes PsENOD12A and PsENOD12B are transcribed and that the relative amounts of PsENOD12A and PsENOD12B mRNA within each tissue are more or less equal. Moreover, the expression pattern during infection and nodule development is the same for the two genes.(ABSTRACT TRUNCATED AT 250 WORDS)