High-risk human papillomavirus genotype distribution among women with gynecology complaints in northwest Ethiopia

BACKGROUND

Human papillomavirus (HPV) genotypes differ by geographic location. With the advent of HPV vaccination and HPV-based cervical screening tests in Ethiopia, a nationwide dataset on the genotype distribution of HPV among women has paramount importance in the fight against cervical cancer. However, there is limited data in this regard in the northwest part of the country. Therefore, this study aimed to identify the genotype distribution of high-risk HPVs among women presenting with cervical abnormalities.

METHODS

A health facility-based cross-sectional study was conducted at Felege Hiwot Comprehensive Specialized Hospital (FHCSH), Bahir Dar-Ethiopia. Women aged ≥ 30 years who visited the hospital gynecology unit from 01 March 2019 to 30 October 2021 were included. Following general and pelvic examinations, a senior gynecologist collected cervical punch biopsies for histopathological examinations and cervical swabs for HR-HPV detection using the Abbott Alinity m system (Abbott Molecular, Des Plaines, IL, USA). Extended genotyping was carried out with the INNO-LiPA HPV Genotyping Extra II assay (INNO-LiPA; Fujirebio Europe, Ghent, Belgium) as per the manufacturer protocols at the Institute of Virology, Leipzig University Hospital, Germany.

RESULTS

We included 355 women with a mean age of 46.4 ± 11.4 years. The majority of the participants, 277 (79.4%) were sexually active before the age of 18 years and 180 (51.6%) had multiple sexual partners. Forty-eight (13.5%) of the participants were HIV positive. The proportion of HR-HPV was 53.0% (n = 188; 95%CI: 47.8-58.1%). From these samples, 13 different HR-HPV types with a total of 258 sequences were identified. The detection of HR-HPV increased significantly with an increase in the age of the participants. The predominant identified HR-HPV was HPV16, 50.4% followed by HPV31 (9.7%), HPV33 (8.5%), HPV39, and HPV68 each (5.8%) and HPV18 (4.7%). Of the total HR-HPV-positive women, 23.9% (45/188) were infected with multiple HR-HPV types. All HPV16, HPV18, HPV35, and HPV45 genotypes (as a single or in coinfections) were found to be associated with either high-grade lesions or cervical cancer.

CONCLUSIONS

HR-HPV infection was reportedly higher among women in the present study area. Based on our findings, we strongly recommend the nonavalent HPV vaccine for immunization and any HPV-based screening method to take into consideration the predominant genotypes circulating in the country. The role of multiple HPV infections in high-grade cervical lesions entails further study in Ethiopia.

Magnitude and genotype of hepatitis delta virus among chronic hepatitis B carriers with a spectrum of liver diseases in Ethiopia

INTRODUCTION AND OBJECTIVES

Chronic hepatitis D infection contributes substantially to the progression of chronic liver disease, especially in most low and middle-income countries, where hepatitis B virus-related chronic liver disease is endemic. Therefore, this study aimed to determine the magnitude and genotype of hepatitis delta virus (HDV) among patients with chronic hepatitis B (CHB)-related liver diseases in Ethiopia.

PATIENTS AND METHODS

In this cross-sectional study, 323 known HBsAg positive individuals comprising 220 patients with CHB-related liver diseases [121 advanced liver diseases (hepatocellular carcinoma /HCC/ and non-HCC) and 99 chronic hepatitis (CH)], and 103 symptomless blood donors (BD) were enrolled. An ELISA kit was employed to determine HDV infection, and quantitative real-time PCR was used to detect HDV RNA. In addition, a non-coding genomic RNA region was sequenced for genotyping and phylogenetic analysis.

RESULTS

Irrespective of the stage of liver disease, the overall magnitude of HDV was 7.7% (25/323). The frequency of anti-HDV increases with the severity of liver disease, 1.9%, 4%, 10%, and 21.3% among BD, CH, non-HCC, and HCC patients, respectively. HDV RNA has been detected in 1.54 %(5/323) cases with a mean viral load of 4,010,360 IU/ml. All isolates were found to be HDV genotype 1.

CONCLUSIONS

The magnitude of HDV infection increased with the severity of liver disease, indicating HDV infection is more common among patients with CHB-related liver diseases in Ethiopia.

Molecular diversity of hepatitis B virus among pregnant women in Amhara National Regional State, Ethiopia

Background

Despite the availability of effective vaccines and treatments for hepatitis B virus (HBV), it continues to be a major public health problem in sub-Saharan Africa including Ethiopia. Routine screening for HBV in pregnant women is widely recommended, but there is lack of screening for HBV during pregnancy in Ethiopia. Therefore, this study aimed to assess viral load, and genetic diversity among pregnant women in the Amhara National Regional State, Ethiopia.

Materials and methods

Hepatitis B surface antigen (HBsAg) testing was performed on 1846 pregnant women, 85 of who tested positive were included in this study. HBV DNA was isolated from 85 positive sera, and the partial surface/polymerase gene was amplified and sequenced. HBV genotypes, sub-genotypes, serotypes and mutations in surface genes and polymerase were studied.

Results

Out of 85 pregnant women`s HBsAg positive sera, 59(69.4%) had detectable viral DNA. The median viral load was 3.4 log IU/ml ranging from 2.6 to7.6 and 46 samples were successfully sequenced and genotyped. Genotypes A and D were identified in 39 (84.8%) and 7 (15.2%); respectively. All genotype A isolates were further classified into sub-genotype A1 and serotype adw2 (84.8%) whereas genotype D isolates were further classified into three sub genotypes; 2 (4.3%) D2, 1(2.2%) D4, and 4 (8.7%) D10 with serotypes ayw2 (10.9%), and ayw3 (4.3%). There were 19 (41.3%) surface gene mutations in the major hydrophilic region (MHR). Six (13.1%) of them were discovered in MHR`s `a’-determinant region. Six polymerase gene mutations (13%) were identified.

Conclusion

Genotype A was the predominant genotype in the Amhara National Regional State. The surface and polymerase gene mutations identified in this study may lead to immune therapy failure, diagnostics escape and drug resistance. Thus, the data generated in this study will contribute to the planning of HBV diagnosis, vaccination and treatment, and most importantly to the prevention of vertical transmission of HBV in Ethiopia. Therefore, further molecular studies on HBV are warranted and continuous surveillance is important for patient management and for the prevention and control of HBV infection in the country.

Molecular Detection of Enteric Viruses in Under-Five Children with Diarrhea in Debre Tabor, Northwest Ethiopia

Background

Viral gastroenteritis belongs to the major public health problems of infant and children worldwide. The largest proportion of morbidity and mortality occurs in Sub-Saharan Africa.

Purpose

Aimed to assess the burden and genetic diversity of enteric viruses among children with diarrhea.

Patients and Methods

A cross-sectional study was undertaken from December 2015 to April 2016 in Debre Tabor. A total of thirty-eight children, who presented with diarrhea at Debre Tabor health centers, were included. Fecal samples were collected and screened for enteric viruses by RT-PCR. Data were analyzed using SPSS software. Descriptive summary techniques were used to display the findings.

Results

Out of thirty-eight children screened, 52.6% were positive for at least one enteric virus. Six (30.0%) of the children had mixed enteric virus infections. Human adenovirus (HAdV) 7 (18.4%) was predominant followed by noroviruses (NoVs) 5 (13.2%), enterovirus (EV) 5 (13.2%), rotavirus A (RVA) 4 (10.5%), human astrovirus (HAstV) 2 (5.3%), and human parechovirus (HPeV) 1 (2.6%). Overall, nineteen different types of enteric virus genotypes were identified. Diverse adenovirus within species A (HAdV-12,-31), B (HAdV-3), C (HAdV-2), and F (HAdV-4) were detected. Norovirus II (GII.4 and GII.6) and norovirus I (GI.2, GI.3, and GI.5) genotypes were found. Sapovirus genotypes within genogroup II (GII.1, GII.5, and GII.6) were identified. Wild-type rotavirus G9 and P[8] genotypes were detected in one of the rotavirus positive samples. Non-polio enteroviruses within species A (coxsackie A virus (CAV) 5, CAV6, and CAV14) and C (enterovirus (EV-C) 99) were also identified. In two of the fecal samples classic HAstV-2 was detected.

Conclusion

Diverse enteric viruses were detected in fecal samples from under-five children with diarrhea. The detection of heterogeneous enteric viruses in this small data set highlights the need for extended multicenter studies to describe the burden and genetic diversity of enteric virus.

Mutated Measles Virus Matrix and Fusion Protein Influence Viral Titer In Vitro and Neuro-Invasion in Lewis Rat Brain Slice Cultures

Measles virus (MV) can cause severe acute diseases as well as long-lasting clinical deteriorations due to viral-induced immunosuppression and neuronal manifestation. How the virus enters the brain and manages to persist in neuronal tissue is not fully understood. Various mutations in the viral genes were found in MV strains isolated from patient brains. In this study, reverse genetics was used to introduce mutations in the fusion, matrix and polymerase genes of MV. The generated virus clones were characterized in cell culture and used to infect rat brain slice cultures. A mutation in the carboxy-terminal domain of the matrix protein (R293Q) promoted the production of progeny virions. This effect was observed in Vero cells irrespective of the expression of the signaling lymphocyte activation molecule (SLAM). Furthermore, a mutation in the fusion protein (I225M) induced syncytia formation on Vero cells in the absence of SLAM and promoted viral spread throughout the rat brain slices. In this study, a solid ex vivo model was established to elucidate the MV mutations contributing to neural manifestation.

Autochthonous West Nile virus infection outbreak in humans, Leipzig, Germany, August to September 2020

Following a distinct summer heat wave, nine autochthonous cases of West Nile fever and West Nile neuroinvasive disease, including one fatality, were observed in Leipzig, Germany, in August and September 2020. Phylogenetic analysis demonstrated close relationships in viruses from humans, animals and mosquitos in eastern Germany, obtained during the preceding 2 years. The described large cluster of autochthonous West Nile virus infections in Germany indicates endemic seasonal circulation of lineage 2 viruses in the area.

No SARS-CoV-2 detected in air samples (pollen and particulate matter) in Leipzig during the first spread

The SARS-CoV-2 pandemic co-occurred with pollen season in Europe 2020 and recent studies suggest a potential link between both. Air samples collected at our measuring station in Leipzig and purified pollen were analyzed for SARS-CoV-2 typical signals or for virus-induced cytopathic effects, to test if the virus could bind to bioaerosols and if so, whether these complexes are infectious. The results show that neither our air samples nor purified pollen were infectious or could act as carrier for virus particles.

Suitcase Lab for Rapid Detection of SARS-CoV-2 Based on Recombinase Polymerase Amplification Assay

In March 2020, the SARS-CoV-2 virus outbreak was declared as a world pandemic by the World Health Organization (WHO). The only measures for controlling the outbreak are testing and isolation of infected cases. Molecular real-time polymerase chain reaction (PCR) assays are very sensitive but require highly equipped laboratories and well-trained personnel. In this study, a rapid point-of-need detection method was developed to detect the RNA-dependent RNA polymerase (RdRP), envelope protein (E), and nucleocapsid protein (N) genes of SARS-CoV-2 based on the reverse transcription recombinase polymerase amplification (RT-RPA) assay. RdRP, E, and N RT-RPA assays required approximately 15 min to amplify 2, 15, and 15 RNA molecules of molecular standard/reaction, respectively. RdRP and E RT-RPA assays detected SARS-CoV-1 and 2 genomic RNA, whereas the N RT-RPA assay identified only SARS-CoV-2 RNA. All established assays did not cross-react with nucleic acids of other respiratory pathogens. The RT-RPA assay's clinical sensitivity and specificity in comparison to real-time RT-PCR (n = 36) were 94 and 100% for RdRP; 65 and 77% for E; and 83 and 94% for the N RT-RPA assay. The assays were deployed to the field, where the RdRP RT-RPA assays confirmed to produce the most accurate results in three different laboratories in Africa (n = 89). The RPA assays were run in a mobile suitcase laboratory to facilitate the deployment at point of need. The assays can contribute to speed up the control measures as well as assist in the detection of COVID-19 cases in low-resource settings.

Flow cytometric measurement of STAT5 phosphorylation in cytomegalovirus-stimulated T cells

Cytomegalovirus (CMV)-specific T cells expand with CMV reactivation and are probably prerequisite for control and protection. Given the critical role STAT5A phosphorylation (pSTAT5A) in T cell proliferation, this study presents a simple and sensitive flow cytometric-based pSTAT5A assay to quickly identify CMV-specific T cell proliferation. We determined pSTAT5A in T cells treated with CMV-specific peptide mix (pp65 + IE1 peptides) from 20 healthy adult subjects and three immunodeficient patients with CARMIL-2 mutation. After stimulation, the percentage of pSTAT5A⁺ T cells in CMV-seropositive (CMV⁺ ) subjects significantly increased from 3.0% ± 1.9% (unstimulated) to 11.4% ± 5.9% (stimulated) for 24 h. After 7 days of stimulation, the percentage of expanded T cells amounted to 26% ± 17.2%. Conversely, the percentage of pSTAT5A⁺ T cells and T cell proliferation from CMV-seronegative (CMV^- ) subjects hardly changed (from 3.0% ± 1.3% to 3.7% ± 1.8% and from 4.3% ± 2.1% to 5.7% ± 1.7%, respectively). We analyzed the correlation between the percentage of pSTAT5A⁺ T cells versus (1) CMV-IgG concentrations versus (2) the percentage of expanded T cells and versus (3) the percentage of initial CMV-specific T cells. In immunodeficient patients with CARMIL-2 mutation, CMV-specific pSTAT5A and T cell proliferation were completely deficient. In conclusion, flow cytometric-based pSTAT5A assay represents an appropriate tool to quickly identify CMV-specific T cell proliferation and helps to understand dysfunctions in controlling other pathogens. Flow cytometric-based pSTAT5A assay may be a useful test in clinical practice and merits further validation in large studies.

Genotyping of enteroviruses and human parechoviruses highlights their diversity in Northwest Ethiopia

Enteroviruses (EVs) and human parechoviruses (HPeVs) infections are associated with various forms of disease, including gastroenteritis. As information on the molecular epidemiology of these viruses is limited in Ethiopia, the genetic diversity of EV and HPeV was investigated in the Northwestern part of the country. Of the total 450 stool samples obtained from infants and young children with diarrhea, 157 (34.9%) were positive for EV and 49 (10.9%) for HPeV RNA when tested by real-time reverse transcription polymerase chain reaction. Genotyping was performed by sequencing of the EV VP1 gene and the HPeV VP3/VP1 gene, respectively. Genotyping of EV was successful in 118 samples. Thereof, 82 (69.5%) belonged to non-polio EVs as a broad range of genotypes within species C, B, and A. Sabin polioviruses were found in 36 cases. HPeV sequences were also heterogeneous with a relative dominance of genotype 3. In conclusion, diverse EV and HPeV genotypes were found cocirculating in Northwest Ethiopia. The findings highlight the importance of continuous surveillance of these viruses in Ethiopia.

Ad hoc laboratory-based surveillance of SARS-CoV-2 by real-time RT-PCR using minipools of RNA prepared from routine respiratory samples

•

A laboratory-based surveillance tool for SARS-CoV-2 was established.

•

It consists of minipool testing of nucleic acid preparations.

•

Limit of detection was 48 copies per reaction (95 % confidence interval: 33–184).

•

A protocol was distributed among five German university hospitals.

•

The approach proved its principle and one COVID-19 case was detected in 70 minipools.

Background

A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in China in late 2019 and subsequently caused a pandemic. Surveillance is important to better appreciate this evolving pandemic and to longitudinally monitor the effectiveness of public health measures.

Objectives

We aimed to provide a rapid, easy to establish and costeffective laboratory-based surveillance tool for SARS-CoV-2. Study design: We used minipools of RNA prepared from nucleic acid extractions of routine respiratory samples. We technically validated the assay and distributed the protocol within an informal network of five German university laboratories.

Results

We tested a total of 70 minipools resembling 700 samples shortly before the upsurge of cases in Germany from 17.02.2020 to 10.03.2020. One minipool reacted positive and after resolution one individual sample tested SARS-CoV-2 positive. This sample was from a hospitalized patient not suspected of having contracted SARS-CoV-2.

Conclusions

Our approach of a laboratory-based surveillance for SARSCoV-2 using minipools proved its concept is easily adaptable and resource-saving. It might assist not only public health laboratories in SARS-CoV-2 surveillance.

Influenza B virus infections in Western Saxony, Germany in three consecutive seasons between 2015 and 2018: Analysis of molecular and clinical features

BACKGROUND

The impact of annual influenza epidemics and prevailing strains varies worldwide and regional. The majority of vaccines used contained two influenza A strains and only one influenza B strain (trivalent vaccine).

AIM

The aim of the study was to compare laboratory confirmed influenza B cases during three consecutive years with respect to vaccination history, clinical symptoms and molecular virology.

METHODS

Partial HA gene sequences were analyzed for lineage determination and complete HA sequence in cases with reported vaccination and in fatal cases. Clinical data were retrieved from patient charts.

FINDINGS

During the 2015/16 season, 75 influenza B cases were retrieved; 11 in 2016/17, and 274 in 2017/18. The frequency of Yamagata-lineage strains increased from 7.6% to 100%. No difference was detected in the relative frequency of co-morbidities in season 2017/18. 37.7% of the adult patients and 4.5% of pediatric patients were vaccinated against influenza.

INTERPRETATION

Phylogenetically, Yamagata strains clustered similarly in 2017/2018 when compared to the previous two influenza seasons. While the relative frequency of influenza B cases differed, the clinical symptoms remained similar.

CONCLUSION

World Health Organization recommendations for the use of tetravalent vaccines that contain two influenza B strains (Yamagata and Victoria) in addition to the two influenza A strains (H1N1 and H3N2) should be implemented in national vaccination guidelines.

FUNDING

This research was partially supported by the Association of Sponsors and Friends of Leipzig University.

Teratogenic Rubella Virus Alters the Endodermal Differentiation Capacity of Human Induced Pluripotent Stem Cells

The study of congenital virus infections in humans requires suitable ex vivo platforms for the species-specific events during embryonal development. A prominent example for these infections is rubella virus (RV) which most commonly leads to defects in ear, heart, and eye development. We applied teratogenic RV to human induced pluripotent stem cells (iPSCs) followed by differentiation into cells of the three embryonic lineages (ecto-, meso-, and endoderm) as a cell culture model for blastocyst- and gastrulation-like stages. In the presence of RV, lineage-specific differentiation markers were expressed, indicating that lineage identity was maintained. However, portrait analysis of the transcriptomic expression signatures of all samples revealed that mock- and RV-infected endodermal cells were less related to each other than their ecto- and mesodermal counterparts. Markers for definitive endoderm were increased during RV infection. Profound alterations of the epigenetic landscape including the expression level of components of the chromatin remodeling complexes and an induction of type III interferons were found, especially after endodermal differentiation of RV-infected iPSCs. Moreover, the eye field transcription factors RAX and SIX3 and components of the gene set vasculogenesis were identified as dysregulated transcripts. Although iPSC morphology was maintained, the formation of embryoid bodies as three-dimensional cell aggregates and as such cellular adhesion capacity was impaired during RV infection. The correlation of the molecular alterations induced by RV during differentiation of iPSCs with the clinical signs of congenital rubella syndrome suggests mechanisms of viral impairment of human development.

Genetic Diversity of Sapoviruses among Inpatients in Germany, 2008-2018

Sapovirus enteric disease affects people of all ages across the globe, in both sporadic cases and outbreak settings. Sapovirus is seldom assessed in Germany and its epidemiology in the country is essentially unknown. Thus, sapovirus occurrence and genetic diversity were studied by real-time reverse transcription polymerase chain reaction (RT-PCR) and partial sequencing of major viral structural protein (VP1) gene in two different sets of stool samples: (1) a selection of 342 diarrheal stools collected from inpatient children during 2008−2009, and (2) 5555 stool samples collected during 2010–2018 from inpatients of all age groups with gastrointestinal complaints. Results showed year-round circulation of sapoviruses, with peaks during cooler months. In total, 30 samples (8.8%) of the first and 112 samples of the second set of samples (2.0%) were sapovirus positive. Capsid gene sequencing was successful in 134/142 samples (94.4%) and showed circulation of all known human pathogenic genogroups. Genotype GI.1 predominated (31.8%), followed by GII.1 (16.7%), GII.3 (14.5%), GI.2 (13.8%) and GV.1 (12.3%). Additionally, minor circulation of GI.3, GI.6, GII.2, GII.4, GII.6 and GIV.1 was shown. Consequently, sapovirus diagnostics need broadly reactive RT-PCR protocols and should particularly be considered in infants and young children. Further studies from other sampling sites are essential to extend our knowledge on sapovirus epidemiology in Germany.

Humoral immunity to varicella zoster virus is altered in patients with rheumatoid arthritis

INTRODUCTION

The prevalence of herpes zoster (HZ) is high in patients with rheumatologic diseases. The incidence in patients with rheumatoid arthritis (RA) is at least twice as high as in healthy people. Nevertheless, little is known about humoral immunity against varicella zoster virus (VZV), in particular in patients with RA. We, therefore, aimed to retrospectively compare VZV antibody concentrations in a collective of patients with RA in a German outpatient clinic with age- and sex-matched controls without RA.

METHODS

We included n = 247 patients with RA from one single university centre as well as n = 250 age- and sex-matched controls from the in-house routine in this retrospective analysis. The concentration of VZV IgG antibody concentration was either available from the records or was measured using an enzyme-linked immunosorbent assay (ELISA). Additionally, avidity for specific IgG was analysed for some of the samples. The antibody concentrations have been compared between the two groups. Moreover, a consecutive subgroup analysis after stratification by age was performed.

RESULTS

A total of 68.4% (n = 169) of the included patients were treated with conventional synthetic DMARDs, either as monotherapy or in combination. Biological originator DMARDs were used in 45.8% (n = 113) of the patients, with the majority (85%, n = 96) of them being on tumour necrosis factor (TNF)-inhibiting agents. As the main result of this study, antibody titres for VZV were found to be significantly lower in RA patients compared with healthy controls (p < 0.0001). The observed difference was most pronounced for the older patients being in the sixth and seventh decade. Antibody avidity was high in both groups with a significantly higher avidity among the controls (p = 0.0006).

CONCLUSIONS

A possible explanation for the low VZV antibody concentration in RA patients might be premature immunosenescence, which most likely also effects the B cell compartment and humoral immunity. This thesis is emphasised by the significantly higher antibody avidity among the controls. The data also suggest that the increased HZ risk is a consequence of a poor humoral immunity. The available HZ vaccinations should contribute to decreasing the elevated HZ risk in RA patients.

KEY POINTS

• Humoral immunity to varicella zoster virus seems to be reduced in patients with RA. • This impaired immunity might contribute to the increased herpes zoster susceptibility in RA patients. • An accelerated immunosenescence in RA could be causative for this finding.

Genetic diversity of human parechoviruses in stool samples, Germany

Human parechoviruses (HPeV) are ubiquitous and mainly occur in early infancy. They are known to cause various clinical manifestations including acute gastroenteritis. To gain insight into the diversity of circulating HPeV genotypes, stool samples from patients (n = 539) with clinical signs of infectious gastroenteritis which showed negative results for other common viral and bacterial enteric pathogens were obtained during three years, 2008 to 2010. Real-time RT-PCR showed HPeV RNA in 34 (6.3%) of the samples. The HPeV detection rate was highest (8.8%) in samples derived from infants and young children under the age of two years. Genotyping was based on VP3/VP1 junction nucleic acid sequences and revealed predominant HPeV-1B (n = 16) and HPeV-3 (n = 12) strains. Those prevailed minor HPeV-6 (n = 3) as well as HPeV-2, -4 and -5 (n = 1, each) strains. To ascertain the assigned HPeV-2 genotype of uncommon strain LPZ04-2008, analysis of complete coding sequences was performed. In complete VP1 analysis strain LPZ04-2008 showed 81.2% nucleic acid identity with HPeV-2 reference strain Williamson. In phylogenetic analysis VP1 of strain LPZ04-2008 clustered with a recent HPeV-2 strain from the UK. Regarding clinical manifestations, severe disease occurred HPeV-1B, -3 and - 6 infections. In conclusion, this paper a high genetic diversity of HPeV in stool samples, including rare strains. The investigation adds data on the whole coding sequences of the rare HPeV-2 strain. Genotyping results confirm previously reported association of more severe illness with HPeV-3 and HPeV-1B strains.

Short Communication: West Nile fever imported from Austria to Germany

This is the first report of West Nile virus (WNV) infection imported by a traveller returning from a neighbouring country to Germany (Austria). Physicians should be aware of the expansion of WNV endemic areas in Europe.

Rubella Virus Strain-Associated Differences in the Induction of Oxidative Stress Are Independent of Their Interferon Activation

Rubella virus (RV) infection impacts cellular metabolic activity in a complex manner with strain-specific nutritional requirements. Here we addressed whether this differential metabolic influence was associated with differences in oxidative stress induction and subsequently with innate immune response activation. The low passaged clinical isolates of RV examined in this study induced oxidative stress as validated through generation of the reactive oxygen species (ROS) cytoplasmic hydrogen peroxide and mitochondrial superoxide. The addition of the cytoplasmic and mitochondrial ROS scavengers N-acetyl-l-cysteine and MitoTEMPO, respectively, reduced RV-associated cytopathogenicity and caspase activation. While the degree of oxidative stress induction varied among RV clinical isolates, the level of innate immune response and interferon-stimulated gene activation was comparable. The type III IFNs were highly upregulated in all cell culture systems tested. However, only pre-stimulation with IFN β slightly reduced RV replication indicating that RV appears to have evolved the ability to counteract innate immune response mechanisms. Through the data presented, we showed that the ability of RV to induce oxidative stress was independent of its capacity to stimulate and counteract the intrinsic innate immune response.

Within-host evolution of virus variants during chronic infection with novel GII.P26-GII.26 norovirus

BACKGROUND

Noroviruses are a leading cause of acute gastroenteritis in all age groups. They generally cause a rapidly self-limiting illness. However, chronic norovirus diarrheal disease occurs in immunocompromised individuals, and is accompanied by persistent shedding of infectious norovirus in stool.

OBJECTIVES

The study aims to characterize a novel GII.P26-GII.26 norovirus strain. Furthermore, it analyses viral mutations arising during chronic infection of an immunocompromised host.

STUDY DESIGN

Over the course of more than three years, stool samples were obtained from an immunocompromised patient and screened for the presence of norovirus RNA by real-time PCR and norovirus antigen by immunoassay. Viral population kinetics was analyzed by conventional and high-throughput-sequencing.

RESULTS

Real-time PCR yielded high amounts of norovirus RNA in the stool, but antigen immunoassays failed to detect the virus. The near complete norovirus genome was assigned as novel GII.P26-GII.26 genotype. Conventional as well as high-throughput sequencing pointed to a heterogeneous viral population with low rates of non-synonymous substitutions. Within-host evolution was enhanced in non-structural protein p22 and the N-terminal arm of the capsid protein VP1 but reduced in the viral polymerase RdRp. Intermittent non-synonymous substitutions in the protruding domain of the VP1 reverted fully over time.

CONCLUSIONS

Confirmation of novel GII.P26-GII.26 norovirus genotypes provides insight into norovirus genetic diversity. The study further illustrates norovirus infection as an important differential diagnosis of recurrent persistent diarrhea in immunocompromised patients. The provided data on within-host evolution contribute to the insight of the mechanisms of viral persistence and pathogenesis in chronic norovirus infections.

Rubella Viruses Shift Cellular Bioenergetics to a More Oxidative and Glycolytic Phenotype with a Strain-Specific Requirement for Glutamine

The flexible regulation of cellular metabolic pathways enables cellular adaptation to changes in energy demand under conditions of stress such as posed by a virus infection. To analyze such an impact on cellular metabolism, rubella virus (RV) was used in this study. RV replication under selected substrate supplementation with glucose, pyruvate, and glutamine as essential nutrients for mammalian cells revealed its requirement for glutamine. The assessment of the mitochondrial respiratory (based on the oxygen consumption rate) and glycolytic (based on the extracellular acidification rate) rate and capacity by respective stress tests through Seahorse technology enabled determination of the bioenergetic phenotype of RV-infected cells. Irrespective of the cellular metabolic background, RV infection induced a shift of the bioenergetic state of epithelial cells (Vero and A549) and human umbilical vein endothelial cells to a higher oxidative and glycolytic level. Interestingly there was a RV strain-specific, but genotype-independent demand for glutamine to induce a significant increase in metabolic activity. While glutaminolysis appeared to be rather negligible for RV replication, glutamine could serve as donor of its amide nitrogen in biosynthesis pathways for important metabolites. This study suggests that the capacity of RVs to induce metabolic alterations could evolve differently during natural infection. Thus, changes in cellular bioenergetics represent an important component of virus-host interactions and could complement our understanding of the viral preference for a distinct host cell population.IMPORTANCE RV pathologies, especially during embryonal development, could be connected with its impact on mitochondrial metabolism. With bioenergetic phenotyping we pursued a rather novel approach in virology. For the first time it was shown that a virus infection could shift the bioenergetics of its infected host cell to a higher energetic state. Notably, the capacity to induce such alterations varied among different RV isolates. Thus, our data add viral adaptation of cellular metabolic activity to its specific needs as a novel aspect to virus-host evolution. In addition, this study emphasizes the implementation of different viral strains in the study of virus-host interactions and the use of bioenergetic phenotyping of infected cells as a biomarker for virus-induced pathological alterations.

Molecular epidemiology of rotaviruses in Northwest Ethiopia after national vaccine introduction

BACKGROUND

Rotaviruses mortality among infants and young children is high in Sub-Saharan Africa. Recently, Ethiopia introduced the monovalent rotavirus vaccine in its national immunization program to decrease the burden of rotavirus disease and mortality. Rotavirus surveillance in Ethiopia is based largely on data provided by sentinel hospitals in its capital Addis Ababa.

OBJECTIVE

To assess rotavirus abundancy and diversity in outpatient infants and children outside of Addis Ababa in the early post-introduction period.

METHOD

Fecal samples were obtained from children aged less than five years presenting with diarrhea at outpatient health institutions in two cities in Northwest Ethiopia, Gondar and Bahir Dar, from November 2015 to April 2016. Basic demographic data were assessed. Real-time RT-PCR was used to detect rotavirus A RNA. Based on sequences of VP4 and VP7 gene segments phylogenetic analysis was performed.

RESULTS

Rotavirus wildtype positivity was 25% (113/450). Rotavirus infection was less common in infants below 6 months than in children of all other age-groups. Rotavirus genotype distributions were distinct between Bahir Dar and Gondar. In total, wildtype G3P[8], G2P[4], G9P[8], G12P[8], and G3P[6] rotaviruses were detected in 68 (60.2%), 21 (18.6%), 13 (11.5%), 9 (8.0%), and 2 (1.8%) of the positive samples, respectively. Wildtype G1P[8] strains were absent. The phylogenetic analysis revealed close relatedness of current rotaviruses with Ethiopian strains of the pre-vaccination period.

CONCLUSION

In the early period after the introduction of vaccination, rotaviruses in Northwestern Ethiopia were frequent in children of 6-59 months and diverse. High phylogenetic relatedness with strains of the pre-vaccine era, indicate absence of early vaccine-induced strain replacement. Future surveillance studies should be carried out throughout the country to gain comprehensive data on rotavirus strain diversity and to monitor the effect of the ongoing vaccine program on the disease burden and eventual rotavirus strain replacement.

Evidence for presumable feline origin of sporadic G6P[9] rotaviruses in humans

Species A rotaviruses are highly diverse and impose a substantial burden to human and animal health. Interspecies transmission between livestock, domestic animals and humans is commonly observed, but spread of animal-like rotaviruses within the human population is limited. During the continued monitoring of rotavirus strains in Germany, an unusual G6P[9] rotavirus strain was detected in feces of a child. The complete rotavirus coding sequences revealed a unique G6-P[9]-I2-R2-C2-M2-A3-N2-T3-E2-H3 genotype constellation. The virus was phylogenetically related to feline G3P[9] strains and other human G6P[9] rotaviruses of presumable zoonotic origin. Analysis of primer binding sites of G6 specific genotyping revealed further evidence of a G6P[9] feline reservoir. Moreover, substantial deficits of conventional semi-nested PCR genotyping approaches in detecting contemporary G6P[9] were revealed. Rotavirus strain GER29-14 most likely resulted from a direct or recent interspecies transmission from a cat to human. Further studies could assess nucleic acid sequences and genotype constellations of feline rotavirus to confirm the likely feline origin of sporadic human G6P[9] strains.

Three novel, multiple recombinant types of species of human mastadenovirus D (HAdV-D 73, 74 & 75) isolated from diarrhoeal faeces of immunocompromised patients

Species D is the largest of the seven species of human mastadenoviruses (HAdV), but few of its multiple types are associated with asevere disease, e.g. epidemic keratoconjunctivitis. Many other types are hardly ever associated with significant diseases in immunocompetent patients, but have been isolated from the diarrhoeal faeces of terminal AIDS patients suggesting their role as opportunistic pathogens. Three novel HAdV-D strains were isolated from the faeces of three immunocompromised adult patients (clinical diagnoses: lymphoma, myelodysplastic syndrome and AIDS CDC3B, respectively). These strains were not typeable by imputed serology of the hexon and fibre gene and therefore complete genomic sequences were generated by next-generation sequencing (NGS). All three strains were multiple recombinants and fulfilled the criteria for designation as types 73, 74 and 75 with the penton/hexon/fibre genotype codes P67H45F27, P70H74F51 and P75H26F29, respectively. A novel genomic backbone and also a novel hexon neutralization epitope sequence were discovered in type 74, and a novel penton sequence in type 75. At the complete genome level, types 73, 74 and 75 were closely related neither to each other nor to type 70, which was previously isolated in the same region. However, these four HAdV-D types were closely related to each other in single genes and gene regions, e.g. penton, E1 and E4 due to recombination events in their phylogeny. In conclusion, regional co-circulation of opportunistic HAdV-D types facilitated co- and super-infections, which are essential for homologous recombination, and thus resulted in the evolution of novel genotypes by lateral gene transfer.

A sensitive one-step TaqMan amplification approach for detection of rubella virus clade I and II genotypes in clinical samples

Although teratogenic rubella virus (RV) causes a vaccine-preventable disease, it is still endemic in several countries worldwide. Thus, there is a constant risk of RV importation into non-endemic areas. RV monitoring, especially during measles and Zika virus outbreaks, requires reliable diagnostic tools. For this study, a TaqMan-based one-step reverse transcription-quantitative PCR (RT-qPCR) assay, with the p90 gene as a novel and so far unexplored target for detection of clade I and II genotypes, was developed and evaluated. Automated nucleic acid extraction was carried out. Performance characteristics of the TaqMan RT-qPCR assay were determined for a RV plasmid standard and RNA extracted from virus-infected cell culture supernatants representing clade I and II genotypes. Diagnostic specificity and sensitivity were validated against other RNA and DNA viruses, relevant for RV diagnostic approaches and for RV-positive clinical samples, respectively. The assay is specific and highly sensitive with a limit of detection as low as five to one copies per reaction or 200 infectious virus particles per ml. The coefficients of variation (CV) were specified as intra- (within one run) and inter- (between different runs) assay variation, and calculated based on the standard deviations for the obtained Ct values of the respective samples. Intra- and inter-assay CV values were low, with a maximum of 3.4% and 2.4%, respectively. The assay was shown to be suitable and specific for the analysis of clinical samples. With p90 as a novel target, the highly sensitive and specific TaqMan assay outlined in this study is suitable for RV diagnosis worldwide.

Arginine methylation enhances the RNA chaperone activity of the West Nile virus host factor AUF1 p45

A prerequisite for the intracellular replication process of the Flavivirus West Nile virus (WNV) is the cyclization of the viral RNA genome, which enables the viral replicase to initiate RNA synthesis. Our earlier studies indicated that the p45 isoform of the cellular AU-rich element binding protein 1 (AUF1) has an RNA chaperone activity, which supports RNA cyclization and viral RNA synthesis by destabilizing a stem structure at the WNV RNA's 3'-end. Here we show that in mammalian cells, AUF1 p45 is consistently modified by arginine methylation of its C terminus. By a combination of different experimental approaches, we can demonstrate that the methyltransferase PRMT1 is necessary and sufficient for AUF1 p45 methylation and that PRMT1 is required for efficient WNV replication. Interestingly, in comparison to the nonmethylated AUF1 p45, the methylated AUF1 p45(aDMA) exhibits a significantly increased affinity to the WNV RNA termini. Further data also revealed that the RNA chaperone activity of AUF1 p45(aDMA) is improved and the methylated protein stimulates viral RNA synthesis considerably more efficiently than the nonmethylated AUF1 p45. In addition to its destabilizing RNA chaperone activity, we identified an RNA annealing activity of AUF1 p45, which is not affected by methylation. Arginine methylation of AUF1 p45 thus represents a specific determinant of its RNA chaperone activity while functioning as a WNV host factor. Our data suggest that the methylation modifies the conformation of AUF1 p45 and in this way affects its RNA binding and restructuring activities.

Hepatitis B Vaccination in End-Stage Pulmonary Disease Patients Evaluated for Lung Transplantation: A Retrospective Single-Center Evaluation

BACKGROUND In times of limited organs for transplantation, anti-HBc-positive organs can be accepted for lung transplantation to increase the number of donors. Transplant recipients should be vaccinated against hepatitis B to prevent HBV infection. However, response after HBV vaccination has only been poorly evaluated in patients with end-stage pulmonary disease. MATERIAL AND METHODS Anti-HBs titers of 40 anti-HBc negative patients with end-stage pulmonary disease evaluated for lung transplantation were analyzed with the Architect® system (Abbott, Germany). Responders, partial responders, or non-responders after HBV vaccination were defined by anti-HBs titers >100 IU/L, 10-100 IU/L, and <10 IU/L, respectively. RESULTS There were 34/40 individuals (85%) vaccinated against hepatitis B, and 6 were not vaccinated. Response, partial response, and non-response after vaccination were observed in 10/34 (29.4%), 11/34 (32.4%), and 13/34 (38.2%) of patients, respectively. Response to vaccination did not correlate with sex, pulmonary disease, comorbidities, immunosuppressive therapy, or smoking status. CONCLUSIONS Although 85% of patients evaluated for lung transplantation were vaccinated against hepatitis B, 38.2% did not show an anti-HBs titer >10 IU/L. Thus, anti-HBs titers should be regularly monitored. Nonresponders should be considered for booster vaccinations, alternative vaccination schedules, or prophylactic treatment with a nucleos(t)ide analogue in case of transplantation of an anti-HBc-positive organ.

HBsAg and anti-HCV screening in elderly hospitalized patients of a German tertiary referral centre

BACKGROUND

Elderly patients are under-represented in hepatitis B and C screening approaches, but may be at increased risk for advanced liver disease. We therefore screened a hospitalized elderly population.

MATERIALS AND METHODS

6011 admissions to the department of internal medicine and neurology within one year were screened for HBsAg and anti-HCV (Elecsys(®)-HBsAg and -anti-HCV). Positive anti-HCV results were confirmed with the INNO-LIA™ assay. HCV-RNA was analyzed by real-time PCR in the case of confirmed positive anti-HCV results, HBV-DNA in the confirmed HBsAg positive individuals.

RESULTS

Patient´s mean age (62.4 years) was 19 years above that of the average German population. The confirmed HBsAg prevalence was 0.6 %. 34 % (n = 12/35) of HBsAg positive cases were newly diagnosed, three of them presented with HBV-DNA levels > 2000 IU/mL. The confirmed anti-HCV prevalence was 0.9 %. 14 % (n = 8/56) of anti-HCV positive patients were previously undiagnosed. HCV-RNA was positive in three of them. In newly diagnosed individuals cirrhosis was present in 1/12 of the HBsAg and in 3/8 of the anti-HCV positive individuals. Compared to non-infected controls, the following risk factors were significantly more frequent in infected patients: (i) HBsAg: sexual exposure (20 % vs. 2 %), blood transfusion before 1992 (13 % vs. 6 %), referrals from nursing homes (10 % vs. 1 %). (ii) Anti-HCV: blood transfusion before 1992 (41 % vs. 6 %), IVDU (25 % vs. 0.5 %), organ transplantation (20 % vs. 5 %), hemodialysis (11 % vs. 3 %).

CONCLUSIONS

HBsAg and anti-HCV were underdiagnosed in a senescent population, however, only few cases presented with advanced liver disease. Referrals from nursing homes were at increased risk for HBV infection.

Activation of the Mitochondrial Apoptotic Signaling Platform during Rubella Virus Infection

Mitochondria- as well as p53-based signaling pathways are central for the execution of the intrinsic apoptotic cascade. Their contribution to rubella virus (RV)-induced apoptosis was addressed through time-specific evaluation of characteristic parameters such as permeabilization of the mitochondrial membrane and subsequent release of the pro-apoptotic proteins apoptosis-inducing factor (AIF) and cytochrome c from mitochondria. Additionally, expression and localization pattern of p53 and selected members of the multifunctional and stress-inducible cyclophilin family were examined. The application of pifithrin μ as an inhibitor of p53 shuttling to mitochondria reduced RV-induced cell death to an extent similar to that of the broad spectrum caspase inhibitor z-VAD-fmk (benzyloxycarbonyl-V-A-D-(OMe)-fmk). However, RV progeny generation was not altered. This indicates that, despite an increased survival rate of its cellular host, induction of apoptosis neither supports nor restricts RV replication. Moreover, some of the examined apoptotic markers were affected in a strain-specific manner and differed between the cell culture-adapted strains: Therien and the HPV77 vaccine on the one hand, and a clinical isolate on the other. In summary, the results presented indicate that the transcription-independent mitochondrial p53 program contributes to RV-induced apoptosis.

No association of oral lichen planus and hepatitis C virus infection in central Germany

OBJECTIVES

Co-occurrence of oral lichen planus (OLP) and chronic hepatitis C virus (HCV) infection suggests a strong association, but the relation between mucocutaneus, autoimmune lichen planus and HCV infection remains unclear. In areas with higher prevalence of HCV infection in general population, like Japan and southern Europe, 20 to 40 % of patients with OLP test positive for anti-HCV antibodies, whereas in German populations, a co-occurrence of 4.2 to 16 % was reported.

MATERIAL AND METHODS

We screened 143 patients with histopathologically proven OLP for prevalence of anti-HCV antibodies. Additionally, we examined 51 anti-HCV-positive subjects with current or past HCV infection for clinical symptoms of OLP. In all patients, confirmatory diagnosis was made by the detection of HCV RNA via reverse transcription-polymerase chain reaction (RT-PCR). A randomized control group comprised 109 blood sera samples of patients without any characteristics of OLP.

RESULTS

The results of all patients showed no co-occurrence in either cohort.

CONCLUSION

In conclusion, no association between oral lichen planus and chronic HCV infection in our study population was found.

CLINICAL RELEVANCE

Anti-HCV antibody screening in patients with confirmed oral lichen planus is not indicated routinely in central Germany.

Limited increase in primary HIV-1C drug resistance mutations in treatment naïve individuals in Ethiopia

Antiretroviral drug resistance is a major challenge for management and control of HIV-1 infection worldwide and particularly in resource limited countries. The frequency of primary drug resistance mutations (DRMs) and of naturally occurring polymorphisms was determined in 83 antiretroviral treatment (ART) naïve Ethiopian individuals infected with HIV-1, consecutively enrolled in 2010. In all individuals HIV-1C was found. The median (interquartile range) of CD4(+) T-cell count and viral load were 100 (49-201) cells/μl and 44,640 (12,553-134,664) copies/ml, respectively. Protease (PR) and reverse transcriptase (RT) genes of HIV-1 RNA were amplified and sequenced. The proportion of primary DRM to any drug class, using the World Health Organization mutation lists, was 7.2% (6/83), thus exceeding the WHO threshold limit of 5%. Three individuals (3.6%) had non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations, two individuals (2.4%) had protease inhibitor mutations, and one (1.2%) had mutations associated with two drug classes (nucleoside reverse transcriptase inhibitor and NNRTI). In addition, the frequency of polymorphisms in the PR and RT genes was higher compared with previous studies in Ethiopian as well as worldwide isolates. Hence, genotypic drug resistance testing as part of routine management of individuals seems reasonable even in resource limited countries prior to treatment in order to allow proper choice of ART.

A renewed focus on the interplay between viruses and mitochondrial metabolism

Mitochondria fulfil several key functions within cellular metabolic and antiviral signalling pathways, including their central role in ATP generation. Viruses, as intracellular parasites, require from their cellular host the building blocks for generation of their viral progeny and the energy that drives viral replication and assembly. While some viruses have adopted ways to manipulate the infected cell such that cellular metabolism supports optimal virus production, other viruses simply exhaust cellular resources. The association of viruses with mitochondria is influenced by several important factors such as speed of the viral replication cycle and viral dependence on cellular enzymes and metabolites. This review will highlight the complex interconnectivity of viral life cycles with the three main mitochondrial metabolic pathways, namely β-oxidation, the tricarboxylic (TCA) cycle, and oxidative phosphorylation. This interconnectivity has the potential to reveal interesting points for antiviral therapy with either prometabolites or antimetabolites and highlights the importance of the viral association with mitochondrial metabolism.

Clinical Relevance of Minimal Residual Viremia during Long-Term Therapy with Nucleos(t)ide Analogues in Patients with Chronic Hepatitis B

BACKGROUND

Successful therapy of chronic hepatitis B with nucleos(t)ide analogues (NUCs) has been defined by undetectable HBV-DNA determined with conventional PCR (lower limit of detection (LLD) 60-80 IU/mL) in clinical registration trials. However, current EASL guidelines recommend highly sensitive real-time PCR (LLD<10-20 IU/mL) and define treatment response by HBV-DNA<10 IU/mL.

AIM

We evaluated frequency and relevance of minimal residual viremia (MRV) during long-term NUC-treatment in a real-life setting.

METHODS

Frozen serum samples (HBV-DNA negative by in-house PCR, LLD <73 IU/mL) were re-analyzed by real-time PCR (LLD<10 IU/mL, Abbott, Germany). MRV was defined by real time PCR positivity and conventional PCR negativity.

RESULTS

237 samples of six HBsAg carriers and 27 NUC-treated CHB patients were analyzed (treatment period 28 (11-111) months, different treatment regimens with mono- or combination therapy). MRV was detected in 31/33 individuals (n = 160/237 serum samples) and more frequent in HBsAg carriers (95%) and HBeAg positive (87%) compared to HBeAg negative patients (53%) (p<0.0001, respectively). Five HBsAg carriers, five HBeAg positive, and four HBeAg negative individuals were continuously HBV-DNA positive. MRV was not significantly more often observed during NUC-monotherapies compared to combination therapies. Concomitant immunosuppressive therapy was present in nine cases and did not influence the results. Viral resistance occurred in three immunocompetent patients with adefovir or lamivudine monotherapy.

CONCLUSIONS

MRV is frequently observed during long-term NUC-therapy. Adjustment of treatment with highly potent NUCs does not seem to be necessary in case of minimal residual viremia in a real-life setting.

Antibody responses in humans infected with newly emerging strains of West Nile Virus in Europe

Infection with West Nile Virus (WNV) affects an increasing number of countries worldwide. Although most human infections result in no or mild flu-like symptoms, the elderly and those with a weakened immune system are at higher risk for developing severe neurological disease. Since its introduction into North America in 1999, WNV has spread across the continental United States and caused annual outbreaks with a total of 36,000 documented clinical cases and ∼1,500 deaths. In recent years, outbreaks of neuroinvasive disease also have been reported in Europe. The WNV strains isolated during these outbreaks differ from those in North America, as sequencing has revealed that distinct phylogenetic lineages of WNV concurrently circulate in Europe, which has potential implications for the development of vaccines, therapeutics, and diagnostic tests. Here, we studied the human antibody response to European WNV strains responsible for outbreaks in Italy and Greece in 2010, caused by lineage 1 and 2 strains, respectively. The WNV structural proteins were expressed as a series of overlapping fragments fused to a carrier-protein, and binding of IgG in sera from infected persons was analyzed. The results demonstrate that, although the humoral immune response to WNV in humans is heterogeneous, several dominant peptides are recognized.

Rubella virus-like replicon particles: analysis of encapsidation determinants and non-structural roles of capsid protein in early post-entry replication

Rubella virus (RUBV) contains a plus-strand RNA genome with two ORFs, one encoding the non-structural replicase proteins (NS-ORF) and the second encoding the virion structural proteins (SP-ORF). This study describes development and use of a trans-encapsidation system for the assembly of infectious RUBV-like replicon particles (VRPs) containing RUBV replicons (self replicating genomes with the SP-ORF replaced with a reporter gene). First, this system was used to map signals within the RUBV genome that mediate packaging of viral RNA. Mutations within a proposed packaging signal did not significantly affect relative packaging efficiency. The insertion of various fragments derived from the RUBV genome into Sindbis virus replicons revealed that there are several regions within the RUBV genome capable of enhancing encapsidation of heterologous replicon RNAs. Secondly, the trans-encapsidation system was used to analyse the effect of alterations within the capsid protein (CP) on release of VRPs and subsequent initiation of replication in newly infected cells. Deletion of the N-terminal eight amino acids of the CP reduced VRP titre significantly, which could be partially complemented by native CP provided in trans, indicating that this mutation affected an entry or post-entry event in the replication cycle. To test this hypothesis, the trans-encapsidation system was used to demonstrate the rescue of a lethal deletion within P150, one of the virus replicase proteins, by CP contained within the virus particle. This novel finding substantiated the functional role of CP in early post-entry replication.

A hospital based study on inter- and intragenotypic diversity of human rotavirus A VP4 and VP7 gene segments, Germany

BACKGROUND

Efforts to reduce the impact of group A rotaviruses on human morbidity and mortality rely on oral immunisation with live attenuated or recombinant vaccines. A major challenge in immunisation is the vast inter- and intragenotypic diversity accomplished by circulating rotaviruses.

OBJECTIVES

To monitor rotavirus inter- and intragenotypic diversity in hospitalised children.

STUDY DESIGN

From January 2008 to December 2009 stool samples from 1994 paediatric in-patients suffering from diarrhoea were screened for rotavirus. Rotavirus G- and P-genotypes were determined by nucleotide sequencing and phylogenetic analysis was performed.

RESULTS

Rotavirus A was detected in stool samples of 341 children, comprising G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], as well as uncommon G12P[6] genotypes and mixed infections. Predominant strains shifted from G1P[8] and G9P[8] genotypes in the first season to G3P[8] and G4P[8] genotypes in the second season. The highest intragenotypic diversity was detected in G1 strains and consisted of co-circulating G1-Ic, G1-Id, G1-Ie and G1-II rotaviruses. The G2 analysis revealed different intragenotypic lineages: G2-IIa, G2-IIb and G2-IIc. Interestingly, the circulating G4-Ib rotaviruses were characterised by insertions of 3 or 6 additional coding nucleotides within variable region 4 of VP7. Whereas different G9-III VP7 gene segments were detected G3-Ia sequences were highly homologous. In the VP4 analysis P[8]-III gene segment predominated over P[4]-Vb, P[8]-I, P[8]-IV and P[6]-I.

CONCLUSIONS

A remarkable rotavirus heterogeneity was detected in the limited local setting and time span. Continued monitoring and nucleotide sequencing is necessary to document possible effects of rising immunisation levels on intragenotypic rotavirus diversity.

Validation and application of normalization factors for gene expression studies in rubella virus-infected cell lines with quantitative real-time PCR

Reference genes are generally employed in real-time quantitative PCR (RT-qPCR) experiments to normalize variability between different samples. The aim of this study was to identify and validate appropriate reference genes as internal controls for RT-qPCR experiments in rubella virus (RV)-infected Vero and MCF-7 cell lines using SYBR green fluorescence. The software programs geNorm and NormFinder and the DeltaDeltaC(t) calculation were used to determine the expression stability and thus reliability of nine suitable reference genes. HPRT1 and HUEL, and HUEL and TBP were identified to be most suitable for RT-qPCR analysis of RV-infected Vero and MCF-7 cells, respectively. These genes were used as normalizers for transcriptional activity of selected cellular genes. The results confirm previously published microarray and Northern blot data, particularly on the transcriptional activity of the cyclin-dependent kinase inhibitor p21 and the nuclear body protein SP100. Furthermore, the mRNA level of the mitochondrial protein p32 is increased in RV-infected cells. The effect on cellular gene transcription by RV-infection seems to be cell line-specific, but genes of central importance for viral life cycle appear to be altered to a similar degree. This study does not only provide an accurate and flexible tool for the quantitative analysis of gene expression patterns in RV-infected cell lines. It also indicates, that the suitability of a reference gene as normalizer of RT-qPCR data and the host-cell response to RV-infection are strictly cell-line specific.

Determination of rubella virus-specific cell-mediated immunity using IFN gamma-ELISpot

Immunity to rubella virus (RV) is conventionally determined by measuring specific immunoglobulin G (IgG). However, several individuals may be considered immune despite undetectable antibody levels. In the present study RV-specific interferon-gamma (IFN gamma)-ELISpot and rubella-IgG-ELISA were compared in 75 young adults aged between 20 and 30 years. In a subgroup, not only rubella-like particles (RLP), but also HPV77 rubella vaccine derived antigen was used in IFN gamma-ELISpot. The results from both, ELISA and ELISpot were independent of previous encounter to RV (vaccination, exanthematous disease, or childhood infection). There was no difference between RLP and RV vaccine antigen in IFN gamma-ELISpot response, and there was no correlation between IFN gamma-ELISpot and RV-specific IgG levels. IFN gamma-producing cells were found in 78.7% of all tested persons, and 83.8% of them were positive in ELISA. In almost all individuals seronegative for RV antibody, IFN gamma-producing cells were detected. Considering both humoral and cell-mediated immune responses, a positive RV immune reaction was seen in 98.6%. The results indicate that the IFN gamma-ELISpot can provide valuable additional information in seronegative individuals.

Human infection with G12 rotaviruses, Germany

Rotavirus group A G12 genotypes were detected in 3 (1.5%) of 198 stool samples positive for human rotavirus. G12P[6] was present in 2 samples, and a mixed G3G12P[8] was found in 1 sample. Phylogenetic analysis of complete open reading frames of all 11 genomic RNA segments proved their Wa-like genogroup affiliation.

Efficacy of measles, mumps and rubella revaccination in children with juvenile idiopathic arthritis treated with methotrexate and etanercept

OBJECTIVES

To evaluate the influence of low-dose MTX and etanercept treatment on efficacy of measles, mumps and rubella (MMR) revaccination in children with juvenile idiopathic arthritis.

METHODS

A prospective nested case-control study was performed to investigate markers of MMR revaccination induced humoral and cell-mediated immunity in 15 patients with juvenile idiopathic arthritis (ages 6-17 yrs), treated with either low-dose MTX therapy alone or in combination with etanercept. The control group consisted of 22 healthy children. Production of IFN-gamma by T memory cells upon in vitro stimulation with measles, mumps and rubella antigens and seroprevalence of virus-specific IgG antibodies were assessed. Medication use, disease activity and patients' comments on side-effects were observed during the period of 6 months before and after revaccination.

RESULTS

Low-dose MTX therapy following MMR vaccination proved not to hamper T-cell mediated immunity in vitro. Neither low-dose MTX nor etanercept treatment, given simultaneously with revaccination, markedly interfered with generation of long-lived virus-restricted T cells and protective levels of virus-specific IgG antibodies. No increase in disease activity or medication use was seen within 6 months after MMR revaccination, including JIA patients using etanercept. No overt measles, mumps, rubella or secondary severe infections were noted.

CONCLUSIONS

Low-dose MTX and etanercept treatment do not seem to interfere with intended outcome of MMR revaccination in children with JIA.

Rubella virus-induced superinfection exclusion studied in cells with persisting replicons

For the first time, homologous superinfection exclusion was documented for rubella virus (RUB) by using Vero cells harbouring persisting RUB replicons. Infection with wild-type RUB was reduced by tenfold, whereas Sindbis virus infection was unaffected. Replication following infection with packaged replicons and transfection with replicon transcripts was also restricted in these cells, indicating that restriction occurred after penetration and entry. Translation of such 'supertransfecting' replicon transcripts was not impaired, but no accumulation of supertransfecting replicon RNA could be detected. We tested the hypothesis favoured in the related alphaviruses that superinfection exclusion is mediated by cleavage of the incoming non-structural precursor by the pre-existing non-structural (NS) protease, resulting in an inhibition of minus-strand RNA synthesis. However, cleavage of a precursor translated from a supertransfecting replicon transcript with an NS protease catalytic-site mutation was not detected and the event in the replication cycle at which superinfection exclusion is executed remains to be elucidated.

Patients at high risk for CMV infection and disease show delayed CD8+ T-cell immune recovery after allogeneic stem cell transplantation

Human cytomegalovirus (CMV) is a major cause of death after transplantation. The frequency of pp65-specific T cells was examined in 38 HLA-A2+ stem cell recipients during the first year after transplantation. Patients were divided into four groups based on donor/recipient serostatus: d+/r+ (n=17), d+/r- (n=7), d-/r+ (n=9) and d-/r- (n=5). Peripheral blood mononuclear cells were stimulated with the CMVpp65 peptide NLVPMVATV, and the specific T-cell frequency was assessed by interferon gamma (IFN-gamma) ELISPOT assay. Responding T cells were characterized by flow cytometry revealing a terminal differentiated effector phenotype. Surveillance of CMV infection was carried out by real-time polymerase chain reaction (n=26) or immunofluorescence (n=12). Infection was present in 7/9 d-/r+ high-risk patients, and CMV disease occurred exclusively in this group with delayed or absent virus-specific T-cell recovery. In contrast, 16/24 intermediate-risk patients showed CMV-specific T cells. Our data suggest that CMV infection and disease rates are elevated in high-risk patients with delayed CMV-specific T-cell immune reconstitution and lower in those with early recovery of T-cell immunity. We recommend preferring CMV seropositive donors for CMV seropositive recipients, as this should lead to durable CMV-specific T-cell responses soon after transplantation with consecutive protection from CMV disease.

Aviäre Influenza und das Schwere Akute Respiratorische Syndrom (SARS) - Erfahrungen und Perspektiven

New respiratory viruses associated with pneumonia have in the past few years been detected in humans. The sudden appearance of the severe acute respiratory syndrome (SARS) in 2003 demonstrated that an emerging and highly infectious disease caused by a hitherto unknown virus was able to spread rapidly, but could finally be contained by stringent measures. The avian influenza A-H5N1-virus of high pathogenicity has crossed in multiple instances the species barriers between humans, mammals, and birds posing a serious pandemic threat. The application of the so far learnt and the continued development of preventive strategies, efficient vaccines, and antiviral substances are besides worldwide surveillance decisive to rapidly detect the repeated, enforced, or new appearance of viruses like the SARS-CoV, influenza A-H5N1 virus, or of new viruses, to contain their spread, and to defeat them.