Impact of the COVID-19 pandemic on norovirus circulation in Germany

Human norovirus is a major cause of viral gastroenteritis in all age groups. The virus is constantly and rapidly changing, allowing mutations and recombination events to create great diversity of circulating viruses. With the start of the COVID-19 pandemic in 2020, a wide range of public health measures were introduced worldwide to control human-to-human transmission of SARS-CoV-2. In Germany, control measures such as distance rules, contact restrictions, personal protection equipment as well as intensive hand hygiene were introduced. To better understand the effect of the measures to control the COVID-19 pandemic on incidence and the molecular epidemiological dynamics of norovirus outbreaks in Germany, we analyzed national notification data between July 2017 and December 2022 and characterized norovirus sequences circulating between January 2018 and December 2022. Compared to a reference period before the pandemic, the incidence of notified norovirus gastroenteritis decreased by 89.7% to 9.6 per 100,000 during the 2020/2021 norovirus season, corresponding to an incidence rate ratio (IRR) of 0.10. Samples from 539 outbreaks were genotyped in two regions of the viral genome from pre-pandemic (January 2018 to February 2020) and samples from 208 outbreaks during pandemic time period (March 2020 to December 2022). As expected, norovirus outbreaks were mainly found in child care facilities and nursing homes. In total, 36 genotypes were detected in the study period. A high proportion of recombinant strains (86%) was found in patients, the proportion of detected recombinant viruses did not vary between the pre-pandemic and pandemic phase. The proportion of the predominant recombinant strain GII.4 Sydney[P16] was unchanged before pandemic and during pandemic at 37.5%. The diversity of most common genotypes in nursing homes and child care facilities showed a different proportion of genotypes causing outbreaks. In nursing homes as well as in child care facilities GII.4 Sydney[P16] was predominant during the whole study period. Compared to the nursing homes, a greater variety of genotypes at the expense of GII.4 Sydney[P16] was detected in child care facilities. Furthermore, the overall proportion of recombinant strain GII.3[P12] increased during the pandemic, due to outbreaks in child care facilities. The COVID-19 pandemic had a high impact on the occurrence of sporadic cases and norovirus outbreaks in Germany, leading to a near suppression of the typical norovirus winter season following the start of the pandemic. The number of norovirus-associated outbreak samples sent to the Consultant Laboratory dropped by 63% during the pandemic. We could not identify a clear influence on circulating norovirus genotypes. The dominance of GII.4 Sydney recombinant strains was independent from the pandemic. Further studies are needed to follow up on the diversity of less predominant genotypes to see if the pandemic could have acted as a bottleneck to the spread of previously minoritized genotypes like GII.3[P12].

Diversity of human astroviruses in Germany 2018 and 2019

Aim of this study was to investigate the molecular diversity of human astroviruses (HAstV) in Germany. A follow-up study was performed with human stool samples collected in 2018-2019, which were genotyped retrospectively. A total of 2645 stool samples, collected between January 2018 and December 2019 from sporadic cases and outbreaks of acute gastroenteritis were analyzed. An algorithm of PCR systems was used to characterize human astrovirus. Human astroviruses were found in 40 samples (positive rate: 1.6%). During the study period, children aged 1-2 years (48%) were most affected by HAstV. Genotyping revealed a number of nine circulating genotypes representing four human Mamastrovirus species. Strain MLB1 was predominant in the study population with a detection rate of 25% followed by HAstV1 with a positive rate of 20%. The diversity of astrovirus genotypes seems to be rather stable in Germany in the last years. A clustering of regionally and/or temporally linked human astroviruses in Germany was not detectable.

Viral gastroenteritis among children of 0-5 years in Nigeria: Characterization of the first Nigerian aichivirus, recombinant noroviruses and detection of a zoonotic astrovirus

BACKGROUND

Viruses are the leading cause of acute gastroenteritis in children worldwide. Understanding of the occurrence and genetic diversity of these viruses can help to prevent infections.

OBJECTIVES

The present study describes the presence, genetic diversity and possible recombination of five enteric viruses in children with gastroenteritis in Southwestern Nigeria.

STUDY DESIGN

From August 2012 to December 2013, stool samples and sociodemographic data of 103 diarrheic children <5 years were collected to detect and characterize rotavirus A, norovirus, human astrovirus, aichivirus and sapovirus using PCR techniques followed by sequencing and phylogenetic analyses.

RESULTS

At least one virus was identified in 58.3% (60/103) of the stool samples. Rotavirus, norovirus and astrovirus were detected in 39.8% (41/103), 10.7% (11/103), and 6.8% (7/103) respectively. Notably, aichivirus was detected for the first time in Nigeria (1/103; 0.97%). Sapovirus was not detected in the study. Co-infections with rotavirus were observed in eight samples either with norovirus or astrovirus or aichivirus. Phylogenetic analyses of different genome regions of norovirus positive samples provided indication for recombinant norovirus strains. A novel astrovirus strain closely related to canine astrovirus was identified and further characterized for the first time.

CONCLUSIONS

Viruses are the common cause of acute gastroenteritis in Nigerian infants with rotavirus as most frequently detected pathogen. New norovirus recombinants and a not yet detected zoonotic astrovirus were circulating in Southwestern Nigeria, providing new information about emerging and unusual strains of viruses causing diarrhea.

Topological bound states in interacting Su-Schrieffer-Heeger rings

We study two-particle states in a Su-Schrieffer-Heeger (SSH) chain with periodic boundary conditions and nearest-neighbor (NN) interactions. The system is mapped into a problem of a single particle in a two-dimensional (2D) SSH lattice with potential walls along specific edges. The 2D SSH model has a trivial Chern number but a non-trivial Zak's phase, the one-dimensional (1D) topological invariant, along specific directions of the lattice, which allow for the presence of topological edge states. Using center-of-mass and relative coordinates, we calculate the energy spectrum of these two-body states for strong interactions and find that, aside from the expected appearance of doublon bands, two extra in-gap bands are present. These are identified as bands of topological states localized at the edges of the internal coordinate, the relative distance between the two particles. As such, the topological states reported here are intrinsically many-body in what concerns their real space manifestation, having no counterpart in single-particle states derived from effective models. Finally, we compare the effect of Hubbard interactions with that of NN interactions to show how the presence of the topological bound states is specific to the latter case.

Co-circulation of classic and novel astrovirus strains in patients with acute gastroenteritis in Germany

OBJECTIVES

In order to analyze the molecular epidemiology of human astroviruses (HAstV) in Germany, a retrospective long-term study was performed to characterize circulating human astrovirus in patients with acute gastroenteritis in Germany.

METHODS

A total of 2877 stool samples, collected between January 2010 and December 2015 from sporadic cases and outbreaks of acute gastroenteritis were retrospectively analyzed for astrovirus. A two-step PCR algorithm was developed and used to identify and characterize human astrovirus infections.

RESULTS

Overall, 143 samples were astrovirus-positive (5.0%). Astrovirus infection was most frequently detectable in samples from children of 3-4 years (15%) followed by children of 1-2 years (8.6%), detection rates in adults were lower (1%-3.6%). A high number (71.3%) of co-infections, mainly with noro- or rotaviruses, were identified. Genotyping revealed that at least ten genotypes from all four human MAstV species were circulating in the study population. HAstV-1 was predominant in different age groups. Novel HAstV (MLB and VA genotypes) were also circulating in Germany.

CONCLUSION

Our findings give new insights into the circulation and genetic diversity of human astroviruses in patients with acute gastroenteritis. The novel HAstV-MLB and -VA genotypes could be characterized firstly in Germany while the analysis showed that these viruses have been dispersed in Germany since 2011 as a causative agent of acute gastroenteritis.

Group A rotaviruses circulating prior to a national immunization programme in Nigeria: Clinical manifestations, high G12P[8] frequency, intra-genotypic divergence of VP4 and VP7

Nigeria having approximately 50 000 Rotavirus A (RVA) deaths annually is yet to introduce RVA vaccine into routine national immunization; therefore surveillance of RVA strains circulating before vaccine introduction is essential in evaluating impact of the intervention. Stool samples and sociodemographic data of diarrhoeic children, <5 years were collected between August 2012 and December 2013. While a high prevalence of RVA infection (47.6%; 49/103) was observed by quantitative reverse transcription real time PCR, only 25% (26/103) had high RVA genome concentrations and were antigen positive. G and P types were obtained for 31 and 37 samples respectively. G12P[8] strains were predominant (30.6%; 16/31); Other genotypes found included G9, G3, G2 and P[4], P[6], P[8]. A G12 + G2/P[8] + P[6] mixed infection was detected. The P[8] genotype showed divergence with strains distributed in lineage III and IV. Compared to the vaccines, changes in antigenic sites of VP8* and VP7 were found. The finding of the G2P[6] genotype combination and emergence of G12 strains support observations in most of the recent RVA studies from Africa. P[6] is common in many African countries, in contrast to countries in Europe and the Americas. In conclusion, this study shows the circulation of other RVA genotypes compared to the common RVA genotypes in Nigeria. PCR results should be interpreted with caution to avoid significant bias from samples with low RVA genome concentrations. These findings provide important information on the detection and molecular epidemiology of RVA prior to vaccination and contribute as a baseline for future evaluations after possible vaccine introduction.

Apolipoprotein E allele frequencies in chronic and self-limited hepatitis C suggest a protective effect of APOE4 in the course of hepatitis C virus infection

BACKGROUND & AIMS

Infectious hepatitis C virus (HCV) particles bind to host lipoproteins such as low-density lipoproteins (LDLs). Low-density lipoprotein receptors (LDLR) have been termed candidate receptors for HCV-LDL complexes. Functional host genetic single nucleotide polymorphisms (SNPs) in the apolipoprotein E (APOE) gene encoding apolipoprotein E (apoE) - a major structural LDL component and natural ligand of LDLR - likely influence the course of HCV infection. We investigated the prevalence of APOE SNPs in two large and independent cohorts of patients with chronic HCV infection compared to respective controls.

METHODS

We genotyped 996 chronically HCV-infected patients; 179 patients with spontaneous HCV clearance; 283 individuals with non-HCV-associated liver disease; and 2 234 healthy controls.

RESULTS

APOE genotype proportions in patients with persistent HCV infection significantly differed from healthy controls (P = 0.007) primarily because of a substantial under-representation of APOE4 alleles in chronically HCV-infected patients (10.2%) compared to 13.0% in healthy controls (P = 0.001). The distribution of APOE4 allele positive genotypes (ε2ε4, ε3ε4, ε4ε4) also significantly differed between chronically HCV-infected patients and healthy controls (1.4%, 17%, 1% vs. 2.4%, 20.5%, 1.7%; P = 0.001), suggesting a protective effect of the APOE4 allele in HCV infection. This was confirmed by a significant over-representation of the APOE4 allele in patients with spontaneous HCV clearance (17.6%; P = 0.00008). The APOE4 allele distribution in patients with non-HCV-associated liver disease (14.0%) was very similar to healthy controls and also differed from chronically HCV-infected patients (P = 0.012), suggesting HCV specificity.

CONCLUSIONS

Our findings suggest that the APOE4 allele may confer a protective effect in the course of HCV infection.

Hypoglycemic Effect of the Methanol flower Extract of Piper Claussenianum and the Major Constituent 2',6'-dihydroxy-4'-methoxychalcone in Streptozotocin Diabetic Rats

Piper claussenianum inflorescences crude methanol extract was tested for hypoglycemic effect in streptozotocin-induced diabetic rats. The blood glucose levels of rats treated with methanol extract were reduced from 318.4±28.1 mg/dl before treatment to 174.2±38.3 mg/dl after 12 days of treatment (P<0.05). Phytochemical studies were carried out on inflorescences methanol crude extract in order to investigate the possible metabolites responsible for the pharmacological properties of the extract. After chromatographic procedures, three flavonoids were isolated and characterized. The major compound 2’,6’-dihydroxy-4’-methoxychalcone was also tested. Rats that received the chalcone content also displayed a reduction in blood glucose levels from 277.4±7.7 mg/dl before treatment to 158.8±9.2 mg/dl after 12 days of treatment (P<0.05). The results suggest this chalcone is one of the metabolite responsible for the blood glucose levels reduction in rats with streptozotocin-induced diabetes. The inflorescence crude extract of P. claussenianum was found to be composed mainly by flavonoids and may be a potential natural source of compounds with hypoglycemic properties.

A novel nerolidol-rich essential oil from Piper claussenianum modulates Candida albicans biofilm

Candidiasis is a major opportunistic fungal infection in humans, and its incidence has increased steadily over the last two decades. Candida albicans, the main species of the genus, has a large arsenal of virulence attributes that contribute to successful infections, such as dimorphism and biofilm formation. The adverse effects of eukaryotic antimicrobial therapies associated with an increase in resistance to the compounds presently available have boosted efforts to improve the therapeutic arsenal against candidiasis with a newer and cheaper range of drugs. In this study, a novel nerolidol-rich essential oil (EO) derived from Piper claussenianum (Miq.) C. DC., Piperaceae, was tested on the growth, transition (yeast to hyphae), formation and stability of biofilms produced by C. albicans. Both inflorescence and leaf EOs were evaluated and revealed MIC values ranging from 0.04 to 0.1 % and 0.2 to 1.26 %, respectively. Furthermore, leaf EO managed to downregulate the yeast-to-hyphae transition by 81 %, as well as reducing biofilm formation by about 30 and 50 % after incubation for 24 and 48 h, respectively. The EO was also able to reduce the viability of pre-formed biofilm by 63.9 %. Finally, the association between the leaf EO and fluconazole was evaluated and revealed an interesting synergistic effect. Taken together, these results demonstrate that this novel compound could be a promising agent and could reinforce the arsenal of therapeutic alternatives for the treatment of candidiasis. Furthermore, it may represent a novel and natural source of nerolidol, which could be of interest pharmaceutically.

Highly sensitive detection of the group A Rotavirus using Apolipoprotein H-coated ELISA plates compared to quantitative real-time PCR

Background

The principle of a capture ELISA is binding of specific capture antibodies (polyclonal or monoclonal) to the surface of a suitable 96 well plate. These immobilized antibodies are capable of specifically binding a virus present in a clinical sample. Subsequently, the captured virus is detected using a specific detection antibody. The drawback of this method is that a capture ELISA can only function for a single virus captured by the primary antibody. Human Apolipoprotein H (ApoH) or β₂-glycoprotein 1 is able to poly-specifically bind viral pathogens. Replacing specific capture antibodies by ApoH should allow poly-specific capture of different viruses that subsequently could be revealed using specific detection antibodies. Thus, using a single capture ELISA format different viruses could be analysed depending on the detection antibody that is applied. In order to demonstrate that this is a valid approach we show detection of group A rotaviruses from stool samples as a proof of principle for a new method of capture ELISA that should also be applicable to other viruses.

Results

Stool samples of different circulating common human and potentially zoonotic group A rotavirus strains, which were pretested in commercial EIAs and genotyped by PCR, were tested in parallel in an ApoH-ELISA set-up and by quantitative real-time PCR (qPCR). Several control samples were included in the analysis. The ApoH-ELISA was suitable for the capture of rotavirus-particles and the detection down to 1,000 infectious units (TCID_50/ml). Subsets of diagnostic samples of different G- and P-types were tested positive in the ApoH-ELISA in different dilutions. Compared to the qPCR results, the analysis showed high sensitivity, specificity and low cross-reactivity for the ApoH-ELISA, which was confirmed in receiver operating characteristics (ROC) analysis.

Conclusions

In this study the development of a highly sensitive and specific capture ELISA was demonstrated by combining a poly-specific ApoH capture step with specific detection antibodies using group A rotaviruses as an example.

Low-density lipoprotein receptor variants are associated with spontaneous and treatment-induced recovery from hepatitis C virus infection

Low-density lipoprotein receptor (LDLR) is involved in the entry of hepatitis C virus (HCV) in host cells. We investigated whether three single-nucleotide alterations within LDLR might be associated with the course of hepatitis C infection and response to antiviral therapy. We enrolled 651 individuals with chronic HCV infection who had received interferon-based combination therapy, 174 individuals with self-limited HCV infection, and 516 healthy controls. LDLR c.1171G>A, c.1413G>A, and c.*52G>A genotyping was performed by real-time PCR-based assays. HCV genotype 1-infected individuals who were homozygous for 3'UTR c.*52G were at increased risk for virologic non-response to antiviral therapy compared to virologic responders (66.3% vs. 51.0%, p=0.001). Furthermore, compared to healthy controls, self-limited HCV genotype 1 infection was significantly associated with c.1171A (15.1% vs. 6.6%, p=0.006) and negatively associated with c.1413G>A heterozygosity (33.0% vs. 46.1%, p=0.023). The data indicate that LDLR alterations are correlated with response to interferon-based combination therapy and with self-limitation of HCV 1 infection.

Personal computer software evaluation in interactive generation of pig liver three-dimensional anatomical images

The efficiency of software for a personal computer in the interactive generation of three-dimensional (3D) images from computer tomography was studied in six pig livers after hepatic resection and catheterization of the hepatic and portal veins. After perfusion the livers were submitted to computed tomography angiography, volumetric measurement by water displacement, and production of an acrylic model of the veins by the injection and corrosion method, by which the lengths of the hepatic and portal veins were measured. From the angiogram, the software generated a 3D image that allowed measurement of the vein lengths. The identified branches of the hepatic and portal veins were correlated with the hepatic sectors and segments, respectively. The virtual measures from the 3D images were compared with the real measures. There were no significant differences between the topography and the vessel length. The mean difference between the volumes calculated from software and those measured by water displacement corresponded to 1.2%, and between the vessel lengths, 0.2%. In conclusion, the software for personal computer (named LIVER3D) is efficient, allowing interactive inspection of 3D images. All virtual measurements of liver vessel length and partial/total liver volume were similar to the actual ones.

[Adjuvant therapy with a glycoprotein IIb-IIa inhibitor (abciximab) in coronary angioplasties with a high thrombotic risk]

INTRODUCTION

We retrospectively studied our experience with adjunctive therapy with glycoprotein IIb-IIIa inhibitor (abciximab) on patients with a high risk of thrombotic complications during coronary angioplasty (PTCA).

PATIENTS AND METHODS

From September 1996 to November 1997, we performed PTCA in 210 patients, and abciximab was given to 38 (18%) of them. The interventions were urgent (primary PTCA in acute myocardial infarction) in 55% of the cases. The mean age of patients was 68.6 +/- 12 years and 71% were male. The reasons for coronary intervention were: acute myocardial infarction in 21 patients (55.3%), unstable angina in 9 (23.7%) and stable angina in 8 (21%). Coronary stents were implanted in 13 patients (34%) and an intra aortic balloon pump was used in 4 (11%). The reasons for using abciximab were: thrombus containing lesion: 22 (57.9%); other type B2/C lesion characteristics: 6 (15.9%); acute closure post balloon PTCA: 9 (23.7%), sub-acute stent thrombosis: 1 (2.6%). Oral acetilsalicilic acid and intravenous heparin were given to all patients at the beginning of the intervention. The mean APTT was 124 +/- 32 seconds at the end of the procedure.

RESULTS

The arterial sheaths (8 French) were removed six hours after procedure, according to the normalisation of APTT values. Angiographic success in this group of patients was 100%. One patient died during hospitalisation due to left ventricular failure. There was no need for repeated angioplasty or coronary bypass grafting during hospital stay. The main complications related to the use of abciximab were: bleeding (requiring transfusion) in four patients 10.5%); severe thrombocytopenia (< 50,000 platelets/mm3): 1 (2.6%): cardiac tamponade (requiring pericardiocentesis): 1 (2.6%) and pseudo-aneurysm of femoral artery (requiring vascular surgery): 1 (2.6%).

CONCLUSIONS

The use of abciximab as adjunctive therapy in this small group of patients undergoing coronary interventions with high risk of thrombotic complications is associated with high procedural success, but at the expense of high rates of bleeding complications. Therefore, special care must be applied during and after the procedure to enhance the safety of the patients treated with this drug.

[Traumatic aortic valve insufficiency]

The traumatic aortic valvular insufficiency (TAVI), through less frequent after a non-penetrating thoracic traumatism, is a serious entity with a very reserved prognosis. So it must be suspected in every patients with signs or symptoms of de novo heart failure post-traumatism. The transthoracic echocardiography and eventually transesophageal echocardiography have a fundamental role in the confirmation of the diagnosis. The clinical picture of traumatic aortic regurgitation is quickly evolutionary and the non efficacy of medical therapy has placed the valvular substitution surgery as the best succeeded treatment. With the advent of the aortic valve repairing surgery some TAVI cases has been submitted to this procedure. Nevertheless, the development of residual aortic regurgitation in these situations, usually requiring later valvular replacement surgery, make the aortic valvuloplasty a controversial surgical technique. The AA describe a recent clinical case of aortic regurgitation after a non-penetrant thoracic traumatism, discussing the aspects connected with physiopathology, diagnosis and therapy. The singularity of this case was based on the fact that the initial clinical diagnosis had been prejudiced by the context of a polytraumatism and there had been a time free of symptoms between the traumatism and the beginning of the symptomatology of left ventricular failure. Even though the identification of the problem allowed an intensive treatment of this serious situation that ended with the replacement of the aortic valve by mechanical aortic prosthesis, with the patient's total recovery.

[Pacemaker implantation in a patient with persistent left superior vena cava and atresia of the right superior vena cava]

Persistent left superior vena cava with absence or atresia of right superior vena cava is a congenital abnormality of systemic venous return to the heart which may complicate the insertion of a pacemaker electrode. We present a case report of a patient with conduction system disturbances in whom this abnormality was diagnosed during pacemaker implantation, with the possibility of using a transvenous electrode without active fixation system.

[Primary tricuspid valve insufficiency. Report of 2 clinical cases]

Two case reports of primary tricuspid regurgitation are presented which diagnoses were made in mean adult life after a long period of few symptoms. The clinical outcome of the two cases was uneven in the sense that only one of them could be corrected with single surgical procedures. Despite relatively rare, this pathology could probably be turned more frequent with a complete and systematic echocardiographic approach. In connection with the reported cases, a review is made of the main etiologies and of some published reports.

[Main left coronary artery disease. Aspects of its diagnosis and treatment]

The Left Main Disease (LMD) assumes a special particularity within the coronary pathology, because of its seriousness and of its urgent need of surgical treatment. The lesion is associated mainly with clinical situations of unstable angina, and who's diagnose by non-invasive methods is extremely difficult; among these methods the echocardiography and specially the stress test still remain of most value in this diagnosis. Coronary arteriography remains the standard exam and is indispensable for a positive confirmation of diagnosis. However, the risk involved here is significantly higher than in other coronary pathologies especially if the lesion of LMD is localized in the proximal region or is ostium level. Therefore, in this review, the need of special care is emphasized before, during and after catheterization, in patients with sunpect of LMD or in those in which the diagnosis was placed during the angiographic examination. Finally, it is very important to recognize the most dangerous situations in order to rightly identify those who need urgent surgical treatment.

[Myocardial infarct in a young man with normal coronary vessels: apropos of a clinical case treated with streptokinase]

The authors report a case of a 31 year old young man who suffered acute myocardial infarction and was subjected to early treatment with streptokinase. The immediate follow-up showed a complete recanalization of the infarct-related vessel, without any identifiable obstructive lesion on coronary arteriography. Related to this angiographic finding, common in myocardial infarction in the young adult, the authors debate the implicated mechanisms, focusing essentially in the relation endothelium-platelets-vasomotricity. The issue of cigarette smoking as a risk factor and its possible pathogenic implication, even in the absence of atherosclerotic plaque, is also approached.