RNA sequencing of avian paramyxovirus (Paramyxoviridae, Avulavirinae) isolates from wild mallards in Belgium, 2021: complete genomes and coinfections

We used untargeted RNA sequencing to characterize three Avulavirinae isolates from pooled samples obtained from wild mallards in Belgium in 2021. The complete genome sequences of two avian Orthoavulavirus-1 (AOAV-1) strains and one avian Paraavulavirus-4 (APMV-4) strain were determined confirming hemagglutination inhibition testing of the virus isolates. In addition, the applied sequencing strategy identified an avian influenza virus (AIV) coinfection in all three virus isolates, confirming weak-positive AIV realtime RT-PCR results from the original sample material. In one AOAV-1 isolate, partial sequences covering all genome segments of an AIV of subtype H11N9 could be de novo assembled from the sequencing data. Besides an AIV coinfection, RNA metagenomic data from the APMV-4 isolate also showed evidence of Alpharetrovirus and Megrivirus coinfection. In total, two AOAV-1 of Class II, genotype I.2 and one APMV-4 complete genome sequences were assembled and compared to publicly available sequences, highlighting the importance of surveillance for poultry pathogens in wild birds. Beyond the insights from full genome characterization of virus isolates, untargeted RNA sequencing strategies provide additional insights in the RNA virome of clinical samples as well as their derived virus isolates that are particularly useful when targeting wild avifauna reservoirs of poultry pathogens.

Height and risk of ischaemic stroke subtypes: a Mendelian randomisation study

Background

Taller adult height is associated with lower risks of ischaemic heart disease in both conventional and Mendelian randomisation studies, providing support for a causal association, but the associations of height with ischaemic stroke and ischaemic stroke subtypes are uncertain.

Purpose

To examine the causal relevance of height for ischaemic stroke and ischaemic stroke subtypes.

Methods

Two-sample Mendelian randomisation analyses were used to examine the associations of height with: (i) ischaemic stroke and ischaemic stroke subtypes in MEGASTROKE (using summary data from 34 217 ischaemic stroke cases), and with (ii) established cardiovascular and other risk factors using individual data from 336 433 participants in UK Biobank and 57 785 in the China Kadoorie Biobank. Instruments for Mendelian randomisation were constructed from up to 3280 height-associated genetic variants, previously identified as having genome-wide significant effects on height.

Results

Genetically-determined taller height was inversely associated with ischaemic stroke (3% [95% CI: 1–6] lower risk per 1 standard deviation taller height) in MEGASTROKE but this masked much stronger opposing associations on risks of different ischaemic stroke subtypes: 15% (95% CI: 9–21) higher risk of cardioembolic stroke, 10% (4–15) lower risk of large-artery atherosclerotic stroke, and 15% (10–20) lower risk of small-vessel stroke (Figure). Genetically-determined taller height was strongly associated with atrial fibrillation and higher lean body mass and lung function but more weakly associated with lower levels of LDL cholesterol and blood pressure.

Conclusions

The findings support a causal association between taller adult height and risk of atrial fibrillation and cardioembolic stroke. The opposing associations of height with other ischaemic stroke subtypes provide further support for considering ischaemic stroke subtypes as distinct diseases in both research and clinical practice.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Medical Research Council, British Heart Foundation

Einfluß von Hyperund Hypothyreose auf den Energiestoffwechsel der Skelettmuskulatur

31P magnetic resonance spectroscopy allows non-invasive evaluation of phosphorus metabolism in man. The purpose of the present study was to assess the influence of hyper- and hypothyroidism on the metabolism of resting human skeletal muscle. The present data show that quantitative measurement of phosphate metabolism by NMR is possible as also demonstrated by other studies. Using a quantitative evaluation method with an external standard, significant differences in the levels of phosphocreatine, adenosintriphosphate, and phosphodiesters were found. In hypothyroid patients a TSH-dependent increase in phosphodiesters and a decrease in adenosintriphosphate and phosphocreatine was observed. In hyperthyroidism a similar decrease in adenosintriphosphate but a considerably higher decrease in phosphocreatine occurred. In the light of the results of other studies of muscle metabolism, these changes appear to be non-specific so that further studies are required to assess the clinical value of such measurements.

Knochenmarkszintigraphie und Kernspintomographie bei malignen Lymphomen: Vergleich mit histologischen Ergebnissen

One hundred and seven patients with malignant Hodgkin and non-Hodgkin lymphoma were examined by bone marrow scintigraphy, MRI of bone marrow and bone marrow biopsy to detect bone marrow infiltration. The study included 2 patients where autopsy findings were subsequently available, 3 patients with blind rebiopsy and one patient with guided rebiopsy. The findings of bone marrow imaging and biopsy were classified as normal (grade 0), suggesting reactive changes of bone marrow (grade 1) or suspicious for infiltration (grade 2). About half of all results of biopsy and imaging methods agreed completely. There was a difference of two steps in the classification in only 2 cases (MRI) and 5 cases (scintigraphy). In patients with chronic lymphocytic leukemia false negative findings by both bone marrow imaging techniques were frequent. Unilateral blind bone marrow biopsy is usually accepted as the golden standard for the presence or absence of tumor infiltration. Although a positive biopsy result must be accepted as proof of bone marrow infiltration, our results indicate that a negative biopsy does not exclude tumor involvement. In all 4 patients with infiltration suspected on MRI or scintigraphy results but with normal findings or reactive changes in the first blind biopsy, blind rebiopsy or guided rebiopsy confirmed the results of the imaging methods. In both patients evaluated at autopsy the preceding MRI and scintigraphy results were confirmed completely, although in both of these patients antemortem biopsy had indicated different findings. Based upon these observations, bone marrow scintigraphy and MRI should be routinely included in the staging of malignant lymphoma as an adjunct to blind bone marrow biopsy in the complete evaluation of bone marrow status.

Knochenmarkveränderungen bei Patienten mit Schilddrüsenkarzinom

In 62 patients with thyroid carcinoma 79 MRI bone marrow examinations and 48 bone marrow scintigraphies were recorded before or following radioiodine therapy, to study the extent of bone marrow expansion. The results of both methods were the same. In 34/79 investigations normal findings were seen, in 18 the bone marrow expanded to the middle third and in 26 to the distal third of the femur. One patient showed bone marrow expansion to the tibia. These results were compared with the following data: histology of tumor, TNM- staging, time passed since thyroidectomy, accumulated doses of radioiodine therapy, results of131I scintigraphy, hematological changes, thyroglobulin level, age and sex. No significant correlations were found between these and the bone marrow imaging results. Bone marrow changes in patients before radioiodine therapy were similar to those in patients treated with up to 48 GBq 131I. Blind biopsy of the posterior iliac crest in five patients showed slightly pathological reactive changes. In only 2/17 follow-up studies an increase of bone marrow expansion was seen. In 8 patients localized findings indicating malignant infiltration were observed. In 4/8 patients metastases of thyroid carcinoma were known or confirmed by pathological radioiodine uptake and in 2/8 metastatic involvement was assumed because of an increased thyroglobulin level.

Usutu virus, Belgium, 2016

During late summer 2016, in a northwest European region extending over Belgium, the Netherlands and the eastern border of the German state of North Rhine Westphalia, an outbreak of wild bird deaths occurred similar to those reported on the continent since 1996. Dead birds were necropsied and examined by complementary methods. Pathologic and immunohistological investigations strongly suggested an infection by Usutu virus. Subsequently, genomic segments of the said virus were detected, the virus was isolated and its complete genome was sequenced. The strain, designated Usutu-LIEGE, is a close phylogenetic relative of those isolated in Germany which form a distinct group within the USUV phylogeny, the so-called Europe_3 lineage. Should this outbreak recapitulate the characteristics of those in southwest Germany in 2011 and in/around Vienna (Austria) in 2001, it is expected that specific avian populations in the affected area will face a significant reduction in size for a few years.

Belgian Wildlife as Potential Zoonotic Reservoir of Hepatitis E Virus

Hepatitis E is an acute human liver disease in healthy individuals but may become chronic in immunocompromised patients. It is caused by the hepatitis E virus (HEV) and can have a zoonotic origin, particularly in high-income countries. In this study, 383 sera from wild boars were selected for serology; for virological analyses, 69 sera and 61 livers from young wild boars were used. A total of 189 and 235 sera of, respectively, red deer and roe deer were collected for serological analysis. For virological analyses, 84 and 68 sera and 29 and 27 livers from, respectively, red and roe deer were sampled. An apparent seroprevalence of 34% (95% CI 29.71-39.46) was found in wild boars, of 1% (95% CI 0-2.4) in red deer and 3% (95% CI 0.8-4.2) in roe deer. To assess the ELISA screening prevalence, Western blot (WB) analyses were carried out, a receiver operating characteristic curve analysis was performed and different scenarios with varying ELISA specificities relative to WB were analysed. Seroprevalence remained high whatever the scenario in the wild boar population. In wild boar, 4 of 69 sera and 4 of 61 livers were detected as positive for HEV RNA. All sequences obtained from sera belonged to genotype HEV-3. HEV RNA, belonging to genotype HEV-3, was detected in one of 29 red deer livers. Wild boar can be considered as a host reservoir of the virus in Belgium. However, in contrast to the epidemiological role played by them in other countries, the low prevalence in deer makes these species an unlikely reservoir. This evidence needs further investigation to determine in which situation deer can serve as reservoir. These results also raise the question of the dynamics of HEV infection between wild fauna, domestic pigs and humans.

Foci report on indigenous Dermacentor reticulatus populations in Belgium and a preliminary study of associated babesiosis pathogens

The occurrence of autochthonous clinical cases of canine and equine babesiosis in Belgium during the last two decades suggests that the vector of the pathogens responsible for these diseases, Dermacentor reticulatus (Ixodida: Ixodidae), may be present in this country. Consequently, evidence for the presence of this tick species in different locations within Belgium was investigated. Four different locations were monitored by flagging in 2010; these included the locations at which D. reticulatus was previously found on a dog in 2009 and on two red deer in 2007. Two different species of tick were identified, Ixodes ricinus (Ixodida: Ixodidae) and D. reticulatus. A total of 282 D. reticulatus adult ticks (98 males, 184 females) were collected from the four sites. Ticks were found mainly from early March until the end of May and a peak in activity was apparent in March. A Babesia spp. (Piroplasmida: Babesiidae) genus-specific polymerase chain reaction test based on the amplification of a fragment of the 18S rRNA gene was used to investigate the potential presence of Babesia spp. All DNA extracts isolated from the total tick samples yielded negative results. Additional studies to accurately determine the distribution and vectorial capacity of this important tick species in Belgium are warranted.

Synthesis of cyclopentapyridine and thienopyridine derivatives as potential calcium channel modulators

In this study, novel condensed 1,4-dihydropyridines bearing cyclopentanone (1-21) or tetrahydrothiophene-1,1-dioxide ring (22-42) with various ester substituents were synthesized via a modified Hantzsch reaction and their calcium channel modulator activities were investigated on isolated rat ileum and rat thoracic aorta. The introduction of a cyclopentanone ring fused to the 1,4-dihydropyridine nucleus and methyl, ethyl and allyl moieties to the ester group led to more active calcium modulators.

Morphological alterations in oxidative muscles and mitochondrial structure associated with equine atypical myopathy

REASONS FOR PERFORMING STUDY

There is a lack of well documented studies about muscular lesions in equine atypical myopathy (EAM).

OBJECTIVES

To characterise morphopathological changes of striated muscles and myocardium, to progress understanding of this disease.

METHODS

Thirty-two horses age 0.5-7 years kept on pasture were referred for a sudden ataxia/myoglobinuria syndrome. Clinical examination (stiffness, muscle pain, muscle fasciculations, abnormal gait, recumbency, myoglobinuria, tachycardia, sweating) and plasma CPK, LDH and AST levels were consistent with extensive myonecrosis and, together with anamnestic data, with so-called 'equine atypical myopathy' (EAM), a disease of unknown aetiology reported since 1939. Macroscopic and microscopic (histology, histoenzymology, ultrastructure) lesions were evaluated.

RESULTS

Necropsic examination revealed large areas of muscle necrosis, the extent and severity of which varied between cases and muscles, but which were clearly more constant and severe in respiratory and postural muscles and in the myocardium. Histology highlighted a multifocal and monophasic process compatible with Zenker degeneration/necrosis that mostly and segmentally affected type 1 fibres. Histochemical evaluation revealed a weak and disorganised pattern of NADH tetrazolium reductase staining, the absence of calcium salts precipitates and a dramatic accumulation of lipid droplets. Ultrastructural examination often revealed fibres of which the sole modifications were altered mitochondria and sarcoplasmic lipidosis.

CONCLUSIONS

Taken together, the data suggest that a primary alteration of mitochondria should be considered, although secondary mitochondrial abnormalities have yet to be ruled out.

POTENTIAL RELEVANCE

The morphological features gathered here reveal that EAM shares most of the characteristics of toxic myopathies.

t-3-Benzyl-r-2,c-6-bis-(4-methoxy-phen-yl)piperidin-4-one oxime

In the title mol-ecule, C(26)H(28)N(2)O(3), the piperidine ring adopts a chair conformation. The two methoxy-phenyl groups attached to the piperidine ring at positions 2 and 6 have equatorial orientations, and make a dihedral angle of 80.72 (15)°. The benzyl group at position 3 has an equatorial orientation. The oxime group at position 4 has a bi-sectional orientation. The ring of the benzyl group makes dihedral angles of 64.71 (16) and 84.79 (17)° with the two benzene rings. Mol-ecules are linked by inter-molecular N-H⋯O, O-H⋯N and C-H⋯O hydrogen bonds, and C-H⋯π inter-actions. There is also a C-H⋯O intra-molecular inter-action.

t-3-Benzyl-r-2,c-6-bis-(4-methoxy-phen-yl)-piperidin-4-one

In the title compound, C(26)H(27)NO(3), the piperidine ring adopts a chair conformation. The two methoxy-phenyl groups attached to the piperidine ring at positions 2 and 6 have equatorial orientations and make a dihedral angle of 87.33 (8)°. The benzyl group at position 3 has an equatorial orientation. The phenyl ring of the benzyl group makes dihedral angles of 75.60 (9) and 73.69 (9)° with the two benzene rings. Mol-ecules are linked by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds and by C-H⋯π inter-actions.

3-Methyl-5-(4-methyl-phen-yl)cyclo-hex-2-enone

In the title mol­ecule, C₁₄H₁₆O, the cyclo­hexene ring adopts an envelope conformation, with all substituents equatorial. Mol­ecules are linked by C—H⋯O hydrogen bonds. A C—H⋯π inter­action involving the benzene ring is also found in the crystal structure. The H atoms of both methyl groups are disordered equally over two positions.

1-Methyl-5-(4-methyl-phen-yl)-3-oxo-cyclo-hexane-1-carbonitrile

In the title mol-ecule, C(15)H(17)NO, the cyclo-hexane ring adopts a chair conformation. The cyano and methyl groups at position 1 have axial and equatorial orientations, respectively. The benzene ring has an equatorial orientation. A C-H⋯π inter-action involving the benzene ring is found in the crystal structure.

6-Meth-oxy-2,3,4,9-tetra-hydro-1H-carbazol-1-one

The carbazole unit of the title mol-ecule, C(13)H(13)NO(2), is not planar. The dihedral angle between the benzene ring and the pyrrole ring is 1.69 (6)°. The cyclo-hexene ring adopts an envelope conformation. Inter-molecular C-H⋯O and N-H⋯O hydrogen bonds are present in the crystal structure. A C-H⋯π inter-action, involving the benzene ring, is also found in the crystal structure.

Optimization of polymerase chain reaction for detection of Clostridium botulinum type C and D in bovine samples

Botulism is a rare but serious paralytic illness caused by a nerve toxin that is produced by the bacterium Clostridium botulinum. The economic, medical and alimentary consequences can be catastrophic in case of an epizooty. A polymerase chain reaction (PCR)-based assay was developed for the detection of C. botulinum toxigenic strains type C and D in bovine samples. This assay has proved to be less expensive, faster and simpler to use than the mouse bioassay, the current reference method for diagnosis of C. botulinum toxigenic strains. Three pairs of primers were designed, one for global detection of C. botulinum types C and D (primer pair Y), and two strain-specific pairs specifically designed for types C (primer pair VC) and D (primer pair VD). The PCR amplification conditions were optimized and evaluated on 13 bovine and two duck samples that had been previously tested by the mouse bioassay. In order to assess the impact of sample treatment, both DNA extracted from crude samples and three different enrichment broths (TYG, CMM, CMM followed by TYG) were tested. A 100% sensitivity was observed when samples were enriched for 5 days in CMM followed by 1 day in TYG broth. False-negative results were encountered when C. botulinum was screened for in crude samples. These findings indicate that the current PCR is a reliable method for the detection of C. botulinum toxigenic strains type C and D in bovine samples but only after proper enrichment in CMM and TYG broth.

Purification of the recombinant beta2 toxin (CPB2) from an enterotoxaemic bovine Clostridium perfringens strain and production of a specific immune serum

Overgrowth of Clostridium perfringens clones with production of one or more of its toxin(s) results in diverse digestive and systemic pathologies in human and animals, such as cattle enterotoxaemia. The so-called beta2 toxin (CPB2) is the most recently described major toxin produced by C. perfringens. In this study, the cpb2 ORF (cpb2FM) from a cattle C. perfringens-associated enterotoxaemia was cloned and sequenced. The cpb2FM and its deduced nucleotide sequence clearly corresponded to the cpb2 allele considered as "consensus" and not to "atypical" allele, despite its "non-porcine" origin. Expression assays of the recombinant toxin CPB2FM were performed in Escherichia coli and Bacillus subtilis with the expression vector pBLTS72, and by genomic integration by double recombination in B. subtilis. Highest level of production was obtained with the expression vector in B. subtilis 168 strain. The recombinant CPB2FM protein was purified and a specific rabbit polyclonal antiserum was produced. Polyclonal antibodies could detect CPB2 production in supernatants of C. perfringens from enterotoxaemic cattle.

The expression of Clostridium perfringens consensus beta2 toxin is associated with bovine enterotoxaemia syndrome

Clostridium perfringens has been implicated in a broad array of enteric infections including the fatal haemorrhagic enteritis/enterotoxaemia syndrome in cattle. The beta2 toxin (CPB2), encoded by cpb2, is suspected to be implicated in this syndrome. However, among C. perfringens isolates from cattle suspected of clostridial disease, an atypical allele was recently found to predominate at the cpb2 locus and atypical corresponding CPB2 proteins were shown to be poorly expressed, thus arguing against a biologically significant role of the beta2 toxin in clostridial diseases in cattle. This study compared genotype and phenotype of the beta2 toxin between C. perfringens isolates from a group of healthy calves (n=14, 87 isolates) and from a group of enterotoxaemic calves (n=8, 41 isolates). PCR results revealed the exclusive presence of the typical "consensus"cpb2 in the enterotoxaemic group. Western blot analysis demonstrated that the typical variant of CPB2 was often expressed in isolates from enterotoxaemic calves (43.9%) and infrequently in isolates from healthy cattle (6.9%). These data suggest that the typical variant of the CPB2 toxin may play a role in the pathogenesis of cattle enterotoxaemia.

Differential Anti-Influenza Activity among Allelic Variants at TheSus Scrofa Mx1Locus

A promising way to oppose infectious challenges would be to improve the resistance of the target species through genetic selection. Theoretically, a candidate gene is available against influenza viruses since a resistance trait was fortuitously discovered in the A2G mouse strain. This trait was demonstrated to be correlated with the expression of a specific isoform of the type I interferon (IFN)-dependent protein MX, an isoform coded by a specific allele at the mouse Mx1 locus. Two allelic polymorphisms were described recently in the Sus scrofa homologous gene. In this study, the frequencies and distribution of both alleles were evaluated among European domestic pig and wild boar populations by PCR-RFLP, and the anti-influenza activity conferred by both MX1 isoforms was evaluated in vitro using transfection of Vero cells followed by flow cytometric determination of the fraction of influenza virus-infected cells among MX-producing and MX-nonproducing cell populations. A significant difference in the anti-influenza activity brought by the two MX1 isoforms was demonstrated, which suggests that a significant improvement of innate resistance of pigs by genetic selection might be feasible provided the differences found here in vitro are epidemiologically relevant in vivo.

Centrosymmetric and pseudo-centrosymmetric structures refined as non-centrosymmetric

The behaviour of the Flack parameter for centrosymmetric and pseudo-centrosymmetric crystal structures based on crystal structures published as being non-centrosymmetric is presented. It is confirmed for centrosymmetric structures that the value obtained for the Flack parameter is critically dependent on the Friedel coverage of the intensity data, approaching 0.5 for a coverage of 100% and sticking near the starting value for a coverage of 0%. For pseudo-centrosymmetric structures, even those very close to being centrosymmetric, it is found that it is often possible to obtain significant values of the Flack parameter. A theoretical basis for this surprising result is established. It has also been possible to establish an a priori estimate of the standard uncertainty of the Flack parameter based only on the chemical composition of the compound and the wavelength of the radiation. The paper concludes with preliminary presentations of bias in the Flack parameter and of inconsistent chemical and crystallographic data.

Studies on condensed 1,4-dihydropyridine derivatives and their calcium modulatory activities

Hexahydroquinoline and furoquinoline derivatives were synthesized and their calcium modulatory activity was investigated on isolated rat ileum and lamb carotid artery. In addition, the in vitro hepatic microsomal biotransformation of one hexahydroquinoline derivative was studied in rat microsomes.

First results of chronic wasting disease (CWD) surveillance in the South‐Eastern part of Belgium

Chronic wasting disease (CWD) has not been reported in Europe, whereas it is considered to be enzootic in free-ranging mule deer, Rocky mountain elk and white-tailed deer in the area of Colorado, Wyoming, and Nebraska, and new foci of CWD have been detected in other parts of the United States. However, no large-scale active epidemiosurveillance of European wild cervids has been installed in Europe. In accordance with the opinion of the European Scientific Steering Committee, a preliminary (active) surveillance scheme was installed, in order to improve the knowledge of the CWD status of the Belgian free-ranging cervids (roe deer and red deer). Spleen samples (n=866) of roe deer and red deer collected in the south-eastern part of Belgium, were examined for CWD using a enzyme-linked immunosorbent assay of Bio-Rad. Afterwards, the ELISA was systematically confirmed by immunohistochemistry using three antibodies, namely R524, 2G11 and 12F10. There were no indications on the occurrence of transmissible spongiform enncephalopathy (TSE) in any of the samples. A Bayesian framework was used for the estimation of the true prevalence of CWD in south-eastern part of Belgium that was estimated to have a median value of zero with a 95% percentile value of 0.00115.