Long-term Outcomes of Revision Total Hip Arthroplasty Using a Modular Fluted Conical Femoral Stem

BACKGROUND

This study presents minimum 6-year follow-up data on the survival and satisfaction of an uncemented modular revision femoral system, following on from our previously published earlier results.

METHODS

We retrospectively reviewed all revision hip arthroplasties performed at our institution between January 2005 and October 2012, using a single modular femoral revision system. Patient-reported outcomes were collected (satisfaction score and Oxford Hip Score). Preoperative and postoperative radiographs were reviewed for stem subsidence, and Kaplan-Meier analysis was performed for survival. A total of 115 femoral revisions were performed in 106 patients.

RESULTS

All-cause survival was 82% (95% confidence interval 74 to 91%) at 10.8 years, and 96% (95% confidence interval 90 to 100%) excluding septic failure. Of the 19 cases requiring reoperation, 16 were for infection, 2 for aseptic loosening, and 1 for mechanical failure. At final follow-up, 88.5% of patients were "satisfied" or "very satisfied".

CONCLUSIONS

This study showed excellent clinical results of a commonly used revision hip stem with at least 10 years follow-up. Satisfaction rates were high, with few aseptic failures. Stem subsidence was more common in revisions for infection, but did not correlate with lower satisfaction scores.

Emergent variant modeling of the serological repertoire to norovirus in young children

Human norovirus is the leading cause of acute gastroenteritis. Young children and the elderly bear the greatest burden of disease, representing more than 200,000 deaths annually. Infection prevalence peaks at younger than 2 years and is driven by novel GII.4 variants that emerge and spread globally. Using a surrogate neutralization assay, we characterize the evolution of the serological neutralizing antibody (nAb) landscape in young children as they transition between sequential GII.4 pandemic variants. Following upsurge of the replacement variant, antigenic cartography illustrates remodeling of the nAb landscape to the new variant accompanied by improved nAb titer. However, nAb relative avidity remains focused on the preceding variant. These data support immune imprinting as a mechanism of immune evasion and GII.4 virus persistence across a population. Understanding the complexities of immunity to rapidly evolving and co-circulating viral variants, like those of norovirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), and dengue viruses, will fundamentally inform vaccine design for emerging pathogens.

Altered Faecal Microbiota Composition and Structure of Ghanaian Children with Acute Gastroenteritis

Acute gastroenteritis (AGE) is a disease of global public health importance. Recent studies show that children with AGE have an altered gut microbiota relative to non-AGE controls. Yet, how the gut microbiota differs in Ghanaian children with and without AGE remains unclear. Here, we explore the 16S rRNA gene-based faecal microbiota profiles of Ghanaian children five years of age and younger, comprising 57 AGE cases and 50 healthy controls. We found that AGE cases were associated with lower microbial diversity and altered microbial sequence profiles relative to the controls. The faecal microbiota of AGE cases was enriched for disease-associated bacterial genera, including Enterococcus, Streptococcus, and Staphylococcus. In contrast, the faecal microbiota of controls was enriched for potentially beneficial genera, including Faecalibacterium, Prevotella, Ruminococcus, and Bacteroides. Lastly, distinct microbial correlation network characteristics were observed between AGE cases and controls, thereby supporting broad differences in faecal microbiota structure. Altogether, we show that the faecal microbiota of Ghanaian children with AGE differ from controls and are enriched for bacterial genera increasingly associated with diseases.

Norovirus attribution study: Detection of norovirus from the commercial food preparation environment in outbreak and non-outbreak premises

AIMS

Norovirus remains the most significant virological risk that is transmitted via food and the environment to cause acute gastroenteritis. This study aimed to investigate the hypothesis that the contamination of the commercial food production environment with norovirus will be higher in premises that have recently reported a foodborne norovirus outbreak than those that have not.

METHODS

Sampling of commercial food production environments was carried out across a 16-month period between January 2015 and April 2016 in the South East and the North West of England by local authority environmental health departments as part of routine surveillance visits to premises. A total of 2982 samples, 2038 virological and 944 bacteriological, were collected from 256 premises. Sixteen of these premises, six from South East and ten from North West England, were sampled as part of a public health outbreak investigation.

RESULTS & CONCLUSIONS

Overall, 2038 swabs were submitted for norovirus testing, with an average of eight swabs per premises (range 4 to 23) and a median of seven. Of the premises sampled, 11.7% (30/256) yielded at least one norovirus-positive sample (environmental, and/or food handler hand swab), and 2.5% of the swabs were positive for norovirus. A peak in the positivity rate was seen in the South East in April 2016. No associations were found between norovirus positivity and bacteriology indicators, or between bacteriology indicators and hygiene ratings.

SIGNIFICANCE AND IMPACT OF STUDY

This study demonstrates that food premises and food handlers remain a potential source of norovirus transmission and outbreaks.

Antigenic Site Immunodominance Redirection Following Repeat Variant Exposure

Human norovirus is a leading cause of acute gastroenteritis, driven by antigenic variants within the GII.4 genotype. Antibody responses to GII.4 vaccination in adults are shaped by immune memory. How children without extensive immune memory will respond to GII.4 vaccination has not been reported. Here, we characterized the GII.4 neutralizing antibody (nAb) landscape following natural infection using a surrogate assay and antigenic site chimera virus-like particles. We demonstrate that the nAb landscape changes with age and virus exposure. Among sites A, C, and G, nAbs from first infections are focused on sites A and C. As immunity develops with age/exposure, site A is supplemented with antibodies that bridge site A to sites C and G. Cross-site nAbs continue to develop into adulthood, accompanied by an increase in nAb to site G. Continued exposure to GII.4 2012 Sydney correlated with a shift to co-dominance of sites A and G. Furthermore, site G nAbs correlated with the broadening of nAb titer across antigenically divergent variants. These data describe fundamental steps in the development of immunity to GII.4 over a lifetime, and illustrate how the antigenicity of one pandemic variant could influence the pandemic potential of another variant through the redirection of immunodominant epitopes.

Using trained dogs and organic semi-conducting sensors to identify asymptomatic and mild SARS-CoV-2 infections: an observational study

BACKGROUND

A rapid, accurate, non-invasive diagnostic screen is needed to identify people with SARS-CoV-2 infection. We investigated whether organic semi-conducting (OSC) sensors and trained dogs could distinguish between people infected with asymptomatic or mild symptoms, and uninfected individuals, and the impact of screening at ports-of-entry.

METHODS

Odour samples were collected from adults, and SARS-CoV-2 infection status confirmed using RT-PCR. OSC sensors captured the volatile organic compound (VOC) profile of odour samples. Trained dogs were tested in a double-blind trial to determine their ability to detect differences in VOCs between infected and uninfected individuals, with sensitivity and specificity as the primary outcome. Mathematical modelling was used to investigate the impact of bio-detection dogs for screening.

RESULTS

About, 3921 adults were enrolled in the study and odour samples collected from 1097 SARS-CoV-2 infected and 2031 uninfected individuals. OSC sensors were able to distinguish between SARS-CoV-2 infected individuals and uninfected, with sensitivity from 98% (95% CI 95-100) to 100% and specificity from 99% (95% CI 97-100) to 100%. Six dogs were able to distinguish between samples with sensitivity ranging from 82% (95% CI 76-87) to 94% (95% CI 89-98) and specificity ranging from 76% (95% CI 70-82) to 92% (95% CI 88-96). Mathematical modelling suggests that dog screening plus a confirmatory PCR test could detect up to 89% of SARS-CoV-2 infections, averting up to 2.2 times as much transmission compared to isolation of symptomatic individuals only.

CONCLUSIONS

People infected with SARS-CoV-2, with asymptomatic or mild symptoms, have a distinct odour that can be identified by sensors and trained dogs with a high degree of accuracy. Odour-based diagnostics using sensors and/or dogs may prove a rapid and effective tool for screening large numbers of people.Trial Registration NCT04509713 (clinicaltrials.gov).

Coaxial laser absorption and optical emission spectroscopy of high-pressure aluminum monoxide

This work advances laser absorption spectroscopy with measurements of aluminum monoxide (AlO) temperature and column density in extreme pressure (P > 60 bar) and temperature (T > 4000 K) environments. Measurements of the AlO A²Π_i-X²Σ⁺ transition are made using a microelectromechanical system, tunable vertical cavity surface emitting laser (MEMS-VCSEL). Simultaneous emission measurements of the AlO B²Σ⁺-X²Σ⁺ transition are made along a line of sight that is coaxial with the laser absorption. Absorption temperature fits agree with emission spectra for a T = 3200 K, P = 9 bar case. In cases with T > 4000 K, P > 60 bar, absorption fits match the ambient temperature while emission fits over-estimate it, owing to high optical depths. These data juxtapose passive and active spectroscopic methods and demonstrate the versatility of AlO laser absorption in high-pressure and high-temperature environments where experimental data remain scarce, and engineering models will benefit from refined measurements.

Measuring transfer of human norovirus during sandwich production: Simulating the role of food, food handlers and the environment

Foodborne outbreaks associated with transmission of norovirus are increasingly becoming a public health concern. Foods can be contaminated with faecal material at the point of production or during food preparation, in both the home and in commercial premises. Transmission of norovirus occurs through the faecal-oral route, either via person-to-person contact or through faecal-contamination of food, water, or environmental surfaces. Understanding the role and pathways of norovirus transmission - either via food handlers' hands, contaminated foods or the environment - remains a key public health priority to reduce the burden of norovirus-associated gastroenteritis. However the proportion of norovirus that is typically transferred remains unknown. Understanding this is necessary to estimate the risk of infection and the burden of gastroenteritis caused by norovirus. In this paper we present a novel method of capture, concentration and molecular detection of norovirus from a wider range of complex food matrices than those demonstrated in existing published methods. We demonstrate that this method can be used as a tool to detect and quantify norovirus from naturally contaminated food, and for monitoring norovirus transfer between food handlers' gloved hands, food or the environment. We measure the effect of introducing contamination at different food production process stages, to the final food product, to determine whether this could cause infection and disease. Between 5.9 and 6.3 Log₁₀ cDNA copies/μl of norovirus GII were inoculated onto food handlers' gloved hands, food or the environment and 1.1-7.4% of norovirus contamination was recovered from all samples tested. When interpreted quantitatively, this percentage equates to levels predicted to be sufficient to cause infection and disease through consumption of the final food product, demonstrating a public health risk. Overall detection and quantification of norovirus from foods, food handlers' gloved hands and the environment, when suspected to be implicated in foodborne transmissions, is paramount for appropriate outbreak investigation.

Phylogenetic Characterization of Crimean-Congo Hemorrhagic Fever Virus Detected in African Blue Ticks Feeding on Cattle in a Ugandan Abattoir

Crimean-Congo hemorrhagic fever virus (CCHFV) is the most geographically widespread of the tick-borne viruses. However, African strains of CCHFV are poorly represented in sequence databases. In addition, almost all sequence data collected to date have been obtained from cases of human disease, while information regarding the circulation of the virus in tick and animal reservoirs is severely lacking. Here, we characterize the complete coding region of a novel CCHFV strain, detected in African blue ticks (Rhipicephalus (Boophilus) decoloratus) feeding on cattle in an abattoir in Kampala, Uganda. These cattle originated from a farm in Mbarara, a major cattle-trading hub for much of Uganda. Phylogenetic analysis indicates that the newly sequenced strain belongs to the African genotype II clade, which predominantly contains the sequences of strains isolated from West Africa in the 1950s, and South Africa in the 1980s. Whilst the viral S (nucleoprotein) and L (RNA polymerase) genome segments shared >90% nucleotide similarity with previously reported genotype II strains, the glycoprotein-coding M segment shared only 80% nucleotide similarity with the next most closely related strains, which were derived from ticks in Western India and Northern China. This genome segment also displayed a large number of non-synonymous mutations previously unreported in the genotype II strains. Characterization of this novel strain adds to our limited understanding of the natural diversity of CCHFV circulating in both ticks and in Africa. Such data can be used to inform the design of vaccines and diagnostics, as well as studies exploring the epidemiology and evolution of the virus for the establishment of future CCHFV control strategies.

Complete genome characterization of human noroviruses allows comparison of minor alleles during acute and chronic infections

Human noroviruses (HuNoVs) circulate globally, affect all age groups and place a substantial burden upon health services. High genetic diversity leading to antigenic variation plays a significant role in HuNoV epidemiology, driving periodic global emergence of epidemic variants. Studies have suggested that immunocompromised individuals may be a reservoir for such epidemic variants, but studies investigating the diversity and emergence of HuNoV variants in immunocompetent individuals are underrepresented. To address this, we sequenced the genomes of HuNoVs present in samples collected longitudinally from one immunocompetent (acute infection) and one immunocompromised (chronic infection) patient. A broadly reactive HuNoV capture-based method was used to concentrate the virus present in these specimens prior to massively parallel sequencing to recover near complete viral genomes. Using a novel bioinformatics pipeline, we demonstrated that persistent minor alleles were present in both acute and chronic infections, and that minor allele frequencies represented a larger proportion of the population during chronic infection. In acute infection, minor alleles were more evenly spread across the genome, although present at much lower frequencies, and therefore difficult to discern from error. By contrast, in the chronic infection, more minor alleles were present in the minor structural protein. No non-synonymous minor alleles were detected in the major structural protein over the short sampling period of the HuNoV chronic infection, suggesting where immune pressure is variable or non-existent, epidemic variants could emerge over longer periods of infection by random chance.

Influence of Nonpolio Enteroviruses and the Bacterial Gut Microbiota on Oral Poliovirus Vaccine Response: A Study from South India

Background

Oral poliovirus vaccine (OPV) is less immunogenic in low- or middle-income than in high-income countries. We tested whether bacterial and viral components of the intestinal microbiota are associated with this phenomenon.

Methods

We assessed the prevalence of enteropathogens using TaqMan array cards 14 days before and at vaccination in 704 Indian infants (aged 6–11 months) receiving monovalent type 3 OPV (CTRI/2014/05/004588). Nonpolio enterovirus (NPEV) serotypes were identified by means of VP1 sequencing. In 120 infants, the prevaccination bacterial microbiota was characterized using 16S ribosomal RNA sequencing.

Results

We detected 56 NPEV serotypes on the day of vaccination. Concurrent NPEVs were associated with a reduction in OPV seroconversion, consistent across species (odds ratio [95% confidence interval], 0.57 [.36–.90], 0.61 [.43–.86], and 0.69 [.41–1.16] for species A, B, and C, respectively). Recently acquired enterovirus infections, detected at vaccination but not 14 days earlier, had a greater interfering effect on monovalent type 3 OPV seroresponse than did persistent infections, with enterovirus detected at both time points (seroconversion in 44 of 127 infants [35%] vs 63 of 129 [49%]; P = .02). The abundance of specific bacterial taxa did not differ significantly according to OPV response, although the microbiota was more diverse in nonresponders at the time of vaccination.

Conclusion

Enteric viruses have a greater impact on OPV response than the bacterial microbiota, with recent enterovirus infections having a greater inhibitory effect than persistent infections.

Technical and surgical causes of outliers after computer navigated total knee arthroplasty

Background

Navigated total knee arthroplasty (TKA) improves implant and limb alignment but outliers continue to exist. This study aimed to determine the technical and surgical causes of outliers.

Methods

This retrospective cohort study included 208 patients who had undergone navigated TKA. Limb and implant alignment indices were measured on post-operative CT scans: mechanical femoro-tibial angle (MFTA); coronal femoral angle (CFA); coronal tibial angle (CTA); sagittal femoral angle (SFA); and sagittal tibial angle (STA). Values outside 0°±3° for MFTA and SFA, 90°±3° for CFA, CTA and STA were considered outliers. Intra-operative navigation data and CT scans were evaluated to categorize the causes of sagittal and coronal plane outliers into hip centre error; ankle centre error; heterogeneous tibial cement mantle; malalignment accepted by surgeon; suboptimal knee balance; and no obvious explanation.

Results

Of the 1040 measurements (five per TKA), the overall incidence of outliers was 10.4% (n = 108). Femoral component outliers (CFA + SFA, n = 51) were all attributable to hip centre error. Tibial component outliers (CTA + STA, n = 43) were attributable to ankle centre error (n = 6), heterogeneous cement mantle (n = 20), malalignment accepted by the surgeon (n = 6) and no obvious cause (n = 11). MFTA outliers were attributable to hip centre error (n = 4) or suboptimal knee balance (n = 10).

Conclusions

Surgeon related errors can be minimized by a meticulous operative technique. These results indicate scope for additional technical improvement, especially in hip centre acquisition, which may further reduce the incidence of outliers.

An interactive data visualisation application to investigate nosocomial transmission of infections

Background: Healthcare-associated infections represent a major threat to patient, staff and visitor safety. Identification of episodes that are likely to have resulted from nosocomial transmission has important implications for infection control. Routinely collected data on ward admissions and sample dates, combined with pathogen genomic information could provide useful insights. We describe a novel, open-source, application for visualising these data, and demonstrate its utility for investigating nosocomial transmission using a case study of a large outbreak of norovirus infection. Methods: We developed the application using Shiny, a web application framework for R. For the norovirus case study, cases were defined as patients who had a faecal sample collected at the hospital in a winter season that tested positive for norovirus. Patient demographics and ward admission dates were extracted from hospital systems. Detected norovirus strains were genotyped and further characterised through sequencing of the hypervariable P2 domain. The most commonly detected sub-strain was visualised using the interactive application. Results: There were 156 norovirus-positive specimens collected from 107 patients. The most commonly detected sub-strain affected 30 patients in five wards. We used the interactive application to produce three visualisations: a bar chart, a timeline, and a schematic ward plan highlighting plausible transmission links. Visualisations showed credible links between cases on the elderly care ward. Conclusions: Use of the interactive application provided insights into transmission in this large nosocomial outbreak of norovirus, highlighting where infection control practices worked well or could be improved. This is a flexible tool that could be used for investigation of any infection in any hospital by interactively changing parameters. Challenges include integration with hospital systems for extracting data. Prospective use of this application could inform better infection control in real time.

An interactive data visualisation application to investigate nosocomial transmission of infections

Background: Healthcare-associated infections represent a major threat to patient, staff and visitor safety. Identification of episodes that are likely to have resulted from nosocomial transmission has important implications for infection control. Routinely collected data on ward admissions and sample dates, combined with pathogen genomic information could provide useful insights. We describe a novel, open-source, application for visualising these data, and demonstrate its utility for investigating nosocomial transmission using a case study of a large outbreak of norovirus infection.

Methods: We developed the application using Shiny, a web application framework for R. For the norovirus case study, cases were defined as patients who had a faecal sample collected at the hospital in a winter season that tested positive for norovirus. Patient demographics and ward admission dates were extracted from hospital systems. Detected norovirus strains were genotyped and further characterised through sequencing of the hypervariable P2 domain. The most commonly detected sub-strain was visualised using the interactive application.

Results: There were 156 norovirus-positive specimens collected from 107 patients. The most commonly detected sub-strain affected 30 patients in five wards. We used the interactive application to produce three visualisations: a bar chart, a timeline, and a schematic ward plan highlighting plausible transmission links. Visualisations showed credible links between cases on the elderly care ward.

Conclusions: Use of the interactive application provided insights into transmission in this large nosocomial outbreak of norovirus, highlighting where infection control practices worked well or could be improved. This is a flexible tool that could be used for investigation of any infection in any hospital by interactively changing parameters. Challenges include integration with hospital systems for extracting data. Prospective use of this application could inform better infection control in real time.

Enterovirus and parechovirus meningitis in infants younger than 90 days old in the UK and Republic of Ireland: a British Paediatric Surveillance Unit study

OBJECTIVES

This study aimed to prospectively collect detailed clinical information for all enterovirus (EV) and human parechovirus (HPeV) meningitis cases in infants aged <90 days in the UK and Ireland.

PARTICIPANTS, DESIGN AND SETTING

Prospective, active national surveillance during July 2014 to July 2015 through the British Paediatric Surveillance Unit. Reporting paediatricians completed questionnaires requesting information on clinical presentation, investigations, management and outcomes at hospital discharge and after 12 months.

MAIN OUTCOME MEASURES

To describe the clinical burden of EV and HPeV meningitis in infants aged <90 days.

RESULTS

During the 13-month surveillance period, 703 cases (668 EV, incidence0.79/1,000 live- births; 35 HPeV, 0.04/1,000 live-births) were identified. The most common clinical presentations were fever (EV: 570/668(85%); HPeV: 28/35(80%)), irritability (EV: 441/668(66%); HPeV: 23/35(66%)) and reduced feeding (EV: 363/668(54%); HPeV 23/35(66%)). Features of circulatory shock were present in 27% (182/668) of EV and 43% (15/35) of HPeV cases. Overall, 11% (76/668) of EV and 23% (8/35) of HPeV cases required intensive care support. Nearly all cases (678/703, 96%) were confirmed by cerebrospinal fluid (CSF) PCR, with 52% (309/600) having normal CSF white cell count for age. Two infants with EV meningitis died (2/668, 0.3%) and four survivors (4/666, 0.6%) had long-term complications at 12 months' follow-up. Infants with HPeV meningitis survived without sequelae. Overall 189 infants had a formal hearing test and none had sensorineural hearing loss.

CONCLUSION

The incidence of laboratory-confirmed EV/HPeV meningitis in young infants is more than twice that for bacterial meningitis. Less than 1% will develop severe neurological complications or die of their infection. Further studies are required to formally assess long-term neurodevelopmental sequelae.

Impact of rotavirus vaccination on rotavirus genotype distribution and diversity in England, September 2006 to August 2016

IntroductionRotavirus vaccination with the live-attenuated monovalent (a G1P[8] human rotavirus strain) two-dose Rotarix vaccine was introduced in England in July 2013. Since then, there have been significant reductions in rotavirus gastroenteritis incidence.AimWe assessed the vaccine's impact on rotavirus genotype distribution and diversity 3 years post-vaccine introduction.MethodsEpidemiological and microbiological data on genotyped rotavirus-positive samples between September 2006 and August 2016 were supplied by EuroRotaNet and Public Health England. Multinomial multivariable logistic regression adjusting for year, season and age was used to quantify changes in genotype prevalence in the vaccine period. Genotype diversity was measured using the Shannon's index (H') and Simpson's index of diversity (D).ResultsWe analysed genotypes from 8,044 faecal samples. In the pre-vaccine era, G1P[8] was most prevalent, ranging from 39% (411/1,057) to 74% (527/709) per year. In the vaccine era, G1P[8] prevalence declined each season (35%, 231/654; 12%, 154/1,257; 5%, 34/726) and genotype diversity increased significantly in 6-59 months old children (H' p < 0.001: D p < 0.001). In multinomial analysis, G2P[4] (adjusted multinomial odds ratio (aMOR): 9.51; 95% confidence interval (CI): 7.02-12.90), G3P[8] (aMOR: 2.83; 95% CI: 2.17-3.81), G12P[8] (aMOR: 2.46; 95% CI: 1.62-3.73) and G4P[8] (aMOR: 1.42; 95% CI: 1.02-1.96) significantly increased relative to G1P[8].ConclusionsIn the context of reduced rotavirus disease incidence, genotype diversity has increased, with a relative change in the dominant genotype from G1P[8] to G2P[4] after vaccine introduction. These changes will need continued surveillance as the number and age of vaccinated birth cohorts increase in the future.

Norovirus strain types found within the second infectious intestinal diseases (IID2) study an analysis of norovirus circulating in the community

BACKGROUND

Norovirus is the commonest cause of infectious intestinal disease (IID) worldwide. In the UK community incidence of norovirus has been estimated at 59/1000 population, equating to four million cases a year. Whilst norovirus infects people of all ages, a substantial burden occurs in infants and young children. The population of viruses found in sporadic cases among infants has been observed to be more diverse than that associated with outbreaks. In this study, we analysed norovirus-positive specimens collected during the second study of infectious intestinal diseases (IID2 Study) a national community cohort study conducted between April 2008 and August 2009 We examined the data for differences in circulating norovirus strains between two arms of a community cohort, and differences between genotypes and disease outcomes such as illness duration and symptom profiles.

METHODS

Analysis was conducted to assess genetic diversity of noroviruses in the community. We also assessed differences in the cycle threshold (Ct) value, as a proxy for viral load, between norovirus genogroups and genotypes, and differences in reported symptoms or length of illness in relation to genogroup and genotype.

RESULTS

There were 477 samples where norovirus was detected. Whilst 85% of people recovered within two days for vomiting; diarrhoea symptoms were reported to day 4 for 83% of the cases, and 10% of people reported symptoms of diarrhoea lasting between five and six days. Both diarrhoea and vomiting symptoms lasted longer in children aged < 5 years compared to adults. There was a significantly higher proportion of GII.4 in samples obtained from the GP arm of the study (chi-square = 17.8, p < 0.001) compared to samples received via post in the self-reporting arm. In the latter group, the prevalence of GII.6 was significantly higher (chi-square = 7.5, p < 0.001).

CONCLUSIONS

We found that there is a difference in disease severity by age group. Children aged < 5 years had longer duration of illness, with 10% still having diarrhoea at seven days, and vomiting of between four and five days. The duration of illness reported is higher overall than one might expect for cases in the community in otherwise healthy individuals which has implications for infection control. No differences were observed in relation to duration of vomiting and or diarrhoea by genotype.

Effectiveness of oral rotavirus vaccination in England against rotavirus-confirmed and all-cause acute gastroenteritis

•

Rotarix® had very good vaccine effectiveness (VE) in UK public health use.

•

Two-dose VE against confirmed infection in young children was 77% (95%CI:66–85%)

•

The vaccine programme was exceptionally successful (>90% vaccine uptake, high VE)

•

Thus, it is highly likely that most acute gastroenteritis (AGE) was no longer due to rotavirus.

•

This explains the lack of demonstrable VE against all-cause AGE.

Background

The monovalent oral rotavirus vaccine Rotarix® was introduced into the UK infant immunisation programme in 2013. We estimated vaccine effectiveness (VE) in the first two years of the programme.

Methods

We used a test-negative case-control design and enhanced national surveillance data for 1869 vaccine-eligible children tested for rotavirus infection to obtain adjusted odds ratios and VE against laboratory-confirmed rotavirus infections. Linked anonymised UK primary care and hospitalisation data from the Clinical Practice Research Datalink (40,723 children) and random-effects Poisson regression were used in a cohort study to estimate VE against all-cause acute gastroenteritis (AGE) and AGE hospitalisations.

Results

VE against laboratory-confirmed infection was 69% (95% Confidence Interval: 40–84%) for one dose and 77% (95%CI: 66–85%) for two doses. Two-dose VE in children aged <12 months and ≥12 months was 85% (95%CI: 74–91%) and 54% (95%CI: 15–75%), respectively. In contrast, we found no evidence that the vaccine was effective against all-cause AGE (VE = −20%, 95%CI: −36% to −5%), or against AGE hospitalisations (VE = 35%, 95% CI: −86% to 77%).

Conclusions

In this first detailed assessment of VE of the Rotarix® vaccine in the English national programme, we show that Rotarix® was highly effective in preventing laboratory-confirmed rotavirus infection in young children. This provides reassurance about the vaccine’s performance in real-life settings and gives key information for future cost-effectiveness analyses. The high VE against rotavirus-specific AGE, and the exceptionally successful implementation of the national rotavirus vaccine programme (with >90% vaccine coverage), explains the lack of VE against all-cause AGE because most AGE in the post-vaccine era would not have been due to rotavirus, although some underestimation of VE could also have occurred due to differential healthcare utilisation by vaccinated and unvaccinated infants. This highlights the importance of using specific vaccine-preventable endpoints for these scenarios.

Estimating the Hospital Burden of Norovirus-Associated Gastroenteritis in England and Its Opportunity Costs for Nonadmitted Patients

Background

Norovirus places a substantial burden on healthcare systems, arising from infected patients, disease outbreaks, beds kept unoccupied for infection control, and staff absences due to infection. In settings with high rates of bed occupancy, opportunity costs arise from patients who cannot be admitted due to beds being unavailable. With several treatments and vaccines against norovirus in development, quantifying the expected economic burden is timely.

Methods

The number of inpatients with norovirus-associated gastroenteritis in England was modeled using infectious and noninfectious gastrointestinal Hospital Episode Statistics codes and laboratory reports of gastrointestinal pathogens collected at Public Health England. The excess length of stay from norovirus was estimated with a multistate model and local outbreak data. Unoccupied bed-days and staff absences were estimated from national outbreak surveillance. The burden was valued conventionally using accounting expenditures and wages, which we contrasted to the opportunity costs from forgone patients using a novel methodology.

Results

Between July 2013 and June 2016, 17.7% (95% confidence interval [CI], 15.6%‒21.6%) of primary and 23.8% (95% CI, 20.6%‒29.9%) of secondary gastrointestinal diagnoses were norovirus attributable. Annually, the estimated median 290000 (interquartile range, 282000‒297000) occupied and unoccupied bed-days used for norovirus displaced 57800 patients. Conventional costs for the National Health Service reached £107.6 million; the economic burden approximated to £297.7 million and a loss of 6300 quality-adjusted life-years annually.

Conclusions

In England, norovirus is now the second-largest contributor of the gastrointestinal hospital burden. With the projected impact being greater than previously estimated, improved capture of relevant opportunity costs seems imperative for diseases such as norovirus.

Methods for ascertaining norovirus disease burdens

Norovirus is the commonest cause of gastrointestinal disease worldwide in. Infections with norovirus occur in all age groups, however, the highest incidence is in children aged less than five years. Surveillance of norovirus is complicated because most people do not contact medical services when they are ill. Nevertheless, Public health laboratory surveillance worldwide has demonstrated the dominance of GII.4 viruses in the population. Better epidemiological surveillance and outbreak investigations, coupled with wider implementation of molecular-based laboratory diagnostics are leading to better estimates of the burden of norovirus infections as well as improved outbreak control. Recent advances in cell culture systems for norovirus and current research investigating the distribution of norovirus-associated disease in the population, for whom the disease burden is greatest, understanding host susceptibility factors, and methodologies for ascertaining cases, are important in increasing our understanding of norovirus. The key to surveillance of norovirus is allying the epidemiology with surveillance of virology. With recent advances in laboratory culture systems for norovirus, next generation sequencing technologies, improved diagnostics and measuring phenotypic characteristics of noroviruses, there are new opportunities to advance understanding of this common and important human pathogen that will help design strategies for vaccine and antiviral development, and how these might be best deployed to control norovirus infection.

Molecular surveillance of norovirus, 2005-16: an epidemiological analysis of data collected from the NoroNet network

BACKGROUND

The development of a vaccine for norovirus requires a detailed understanding of global genetic diversity of noroviruses. We analysed their epidemiology and diversity using surveillance data from the NoroNet network.

METHODS

We included genetic sequences of norovirus specimens obtained from outbreak investigations and sporadic gastroenteritis cases between 2005 and 2016 in Europe, Asia, Oceania, and Africa. We genotyped norovirus sequences and analysed sequences that overlapped at open reading frame (ORF) 1 and ORF2. Additionally, we assessed the sampling date and country of origin of the first reported sequence to assess when and where novel drift variants originated.

FINDINGS

We analysed 16 635 norovirus sequences submitted between Jan 1, 2005, to Nov 17, 2016, of which 1372 (8·2%) sequences belonged to genotype GI, 15 256 (91·7%) to GII, and seven (<0·1%) to GIV.1. During this period, 26 different norovirus capsid genotypes circulated and 22 different recombinant genomes were found. GII.4 drift variants emerged with 2-3-year periodicity up to 2012, but not afterwards. Instead, the GII.4 Sydney capsid seems to persist through recombination, with a novel recombinant of GII.P16-GII.4 Sydney 2012 variant detected in 2014 in Germany (n=1) and the Netherlands (n=1), and again in 2016 in Japan (n=2), China (n=8), and the Netherlands (n=3). The novel GII.P17-GII.17, first reported in Asia in 2014, has circulated widely in Europe in 2015-16 (GII.P17 made up a highly variable proportion of all sequences in each country [median 11·3%, range 4·2-53·9], as did GII.17 [median 6·3%, range 0-44·5]). GII.4 viruses were more common in outbreaks in health-care settings (2239 [37·2%] of 6022 entries) compared with other genotypes (101 [12·5%] of 809 entries for GI and 263 [13·5%] of 1941 entries for GII non-GII.Pe-GII.4 or GII.P4-GII.4).

INTERPRETATION

Continuous changes in the global norovirus genetic diversity highlight the need for sustained global norovirus surveillance, including assessment of possible immune escape and evolution by recombination, to provide a full overview of norovirus epidemiology for future vaccine policy decisions.

FUNDING

European Union's Horizon 2020 grant COMPARE, ZonMw TOP grant, the Virgo Consortium funded by the Dutch Government, and the Hungarian Scientific Research Fund.

Prospective cohort study to investigate the burden and transmission of acute gastroenteritis in care homes: a study protocol

INTRODUCTION

Noroviruses are the leading cause of acute gastroenteritis in all age groups, but illness is more severe and causes excess mortality in the elderly, particularly those in long-term care. The total burden of norovirus disease in the elderly in the UK is poorly defined; no current surveillance programmes systematically or accurately quantify norovirus infection in those living in care homes. The aim of this study is to evaluate an enhanced surveillance system for acute gastroenteritis among the elderly in care homes.

METHODS AND ANALYSIS

We will conduct this prospective cohort study in care homes in North West England; residents and staff at study care homes will be asked to participate. We will prospectively enrol a cohort of participants in an enhanced surveillance system to capture the incidence of acute gastroenteritis and use multiplex PCR to detect pathogens. We will sample symptomatic and non-symptomatic participants to understand characteristics of norovirus disease and susceptibility to infection. We will generate novel data on transmission dynamics by collecting data on the pattern of interactions within care homes using electronic proximity sensors. Comparisons of outbreak and non-outbreak periods will be used to quantify the impact of norovirus outbreaks on care homes.

ETHICS AND DISSEMINATION

The study has been approved by the North West-Greater Manchester South NHS Research Ethics Committee (REC Reference: 16/NW/0541). Study outputs will be disseminated through scientific conferences and peer-reviewed publications. This study will provide detailed insight on the burden and aetiology of acute gastroenteritis in care homes, in addition to generating novel data on transmission dynamics and risks. The study will identify areas for improving infection control practice and allow more accurate modelling of the introduction of interventions such as vaccination.

Computer Navigation Helps Reduce the Incidence of Noise After Ceramic-on-Ceramic Total Hip Arthroplasty

BACKGROUND

Noise after ceramic-on-ceramic (CoC) total hip arthroplasty (THA) is a well-recognized problem. Computer navigation has been shown to achieve desired implant orientation. Our aim was (1) to compare the incidence of noise between navigated and conventional CoC THAs and (2) to determine the factors associated with noise.

METHODS

All patients undergoing CoC THA between March 2009 and August 2012 were considered for this study. Information regarding hip noise was obtained via telephone or postal interview. A comparable cohort of patients in navigated and conventional groups was used to evaluate the incidence of noise.

RESULTS

A total of 375 CoC THAs using the same implant (202 navigated and 173 conventional) were evaluated. Patients <65 years of age had significantly greater incidence of noise (22.4% vs 6.1%; P < .001). To ensure similarity, a subgroup of cohort <65 years and a 32-mm head size was used to compare the incidence of noise between the navigated (68 THAs) and conventional (118 THAs) groups. Overall incidence of noise was significantly greater in the conventional group (28%) as compared with the navigated group (10%; P = .005). The relative risk of noise for the conventional vs the navigated group was 2.7 (P = .01), and for squeaking was 1.9 (P = .2). Squeaking THAs had significantly lower cup anteversion (13.4° ± 5.2°) as compared with the silent THAs (17.6° ± 6.9°; P = .01).

CONCLUSION

Navigated CoC THAs were 2.7× less likely to have noise as compared with the conventional ones. Squeaking THAs had significantly lower cup anteversion as compared with the silent ones. Patients of age <65 years had significantly greater incidence of noise after CoC THA.

A randomized controlled trial to compare component placement in navigated total knee arthroplasty using original and streamlined registration processes

Background

This randomized controlled trial validated a redesigned version of navigated total knee arthroplasty software with a streamlined registration (Smart) against the previous version (Classic). The objectives were to determine if Smart software had the same accuracy of component positioning and whether registration and operative time were reduced.

Methods

A total of 220 patients were recruited and had a navigated total knee arthroplasty performed. With the exception of the software, all patients had the same perioperative care. At 6-week follow-up with an independent arthroplasty service, all patients had a computerized tomography scan. This was assessed by an independent radiologist to measure the mechanical alignment of the components.

Results

The mean postoperative mechanical femorotibial angles were equivalent between groups (mean difference −0.2°, 95% confidence interval −0.7° to 0.3°, P = .407). Component positions were similar in both groups. Mean registration time was significantly shorter for the Smart group (2 minutes 30 seconds ± 54 seconds) than the Classic group (3 minutes 23 seconds ± 39 seconds), P < .001. The mean operative time was 72 ± 12 minutes in both groups (P = .855). At 6-week follow-up, both groups had similar clinical outcomes with 96.5% of patients being satisfied or very satisfied.

Conclusions

The study verified that a reduced registration time did not alter the accuracy of component placement. However, despite a shorter registration time, the overall surgical time was not reduced.

Total Hip Arthroplasty Improves Pain and Function but Not Physical Activity

BACKGROUND

People with hip osteoarthritis are likely to limit physical activity (PA) engagement due to pain and lack of function. Total hip arthroplasty (THA) reduces pain and improves function, potentially allowing increased PA. PA of THA patients was quantified to 12 months postoperation. The hypothesis was that postoperatively levels of PA would increase.

METHODS

PA of 30 THA patients (67 ± 7 years) was objectively measured preoperatively and 3 and 12 months postoperation. Harris Hip Score (HHS), Oxford Hip Score (OHS), and 6-minute walk test (6MWT) were recorded. Mixed linear modelling was used to examine relationships of outcomes with time, baseline body mass index (BMI), age, gender, and baseline HHS.

RESULTS

Time was not a significant factor in predicting volume measures of PA, including sit-to-stand transitions, upright time, and steps. Notably, baseline BMI was a significant predictor of upright time, steps, largest number of steps in an upright bout, HHS, and 6MWT. Baseline HHS helped predict longest upright bout, cadence of walking bouts longer than 60 seconds, and OHS. The significant effect of participant as a random intercept in the model for PA outcomes suggested habituation from presurgery to postsurgery.

CONCLUSION

Volume measures of PA did not change from presurgery to 12 months postsurgery despite improvement in HHS, OHS, and 6MWT. Baseline BMI was a more important predictor of upright activity and stepping than time. Preoperative and postoperative PA promotion could be used to modify apparently habitual low levels of PA to enable full health benefits of THA to be gained.

The emerging GII.P16-GII.4 Sydney 2012 norovirus lineage is circulating worldwide, arose by late-2014 and contains polymerase changes that may increase virus transmission

Noroviruses are a leading cause of human gastroenteritis worldwide. The norovirus genotype GII.4 is the most prevalent genotype in the human population and has caused six pandemics since 1995. A novel norovirus lineage containing the GII.P16 polymerase and pandemic GII.4 Sydney 2012 capsid was recently detected in Asia and Germany. We demonstrate that this lineage is also circulating within the UK and USA and has been circulating since October 2014 or earlier. While the lineage does not contain unique substitutions in the capsid, it does contain polymerase substitutions close to positions known to influence polymerase function and virus transmission. These polymerase substitutions are shared with a GII.P16-GII.2 virus that dominated outbreaks in Germany in Winter 2016. We suggest that the substitutions in the polymerase may have resulted in a more transmissible virus and the combination of this polymerase and the pandemic GII.4 capsid may result in a highly transmissible virus. Further surveillance efforts will be required to determine whether the GII.P16-GII.4 Sydney 2012 lineage increases in frequency over the coming months.

Mitochondrial Inner Membrane Depolarization as a Marker of Platelet Apoptosis : Disclosure of Nonapoptotic Membrane Depolarization

Availability of universal marker for the diagnosis of platelet apoptosis is an important but currently unresolved goal of platelet physiology investigations. Mitochondrial inner transmembrane potential (▵Ψm) depolarization is frequently used as a marker of apoptosis in nucleated cells and anucleate platelets. Since ▵Ψm depolarization in platelets is also frequently associated with concurrent induction of other apoptotic responses, it may appear that ▵Ψm depolarization is a good universal marker of platelet apoptosis. However, data presented in the current study indicate that this is incorrect. We report here fundamental differences in the effects of potassium ionophore valinomycin and calcium ionophore A23187 on human platelet apoptosis. Although both A23187-triggered and valinomycin-triggered ▵Ψm depolarization are strongly induced, the former is dependent on the opening of mitochondrial permeability transition pore (MPTP) and the latter is MPTP-independent. Furthermore, effects of calcium and potassium ionophores on other apoptotic events are also basically different. A23187 induces caspase-3 activation, proapoptotic Bax and Bak protein expression, phosphatidylserine exposure, and microparticle formation, whereas valinomycin does not induce these apoptotic manifestations. Discovery of targeted ▵Ψm depolarization not associated with apoptosis in valinomycin-treated platelets indicates that this marker should not be used as a single universal marker of platelet apoptosis in unknown experimental and clinical settings as it may lead to a false-positive apoptosis diagnosis.

Antibodies against Lewis antigens inhibit the binding of human norovirus GII.4 virus-like particles to saliva but not to intestinal Caco-2 cells

Background

Human noroviruses (NoVs) are the main cause of gastroenteritis worldwide. The most commonly detected NoV strains belong to the genetically diverse GII.4 genotype, with new pandemic variants emerging periodically. Despite extensive efforts, NoV investigation has been hampered by the lack of an effective in vitro cell culture system. However, NoV-derived recombinant virus-like particles (VLPs) resembling empty capsids are good surrogates for analysing NoV antigenicity and virus-ligand interactions. NoV VLPs have been reported to bind to histo-blood group antigens (HBGAs). We have analysed the ability of NoV VLPs derived from GI.1 genotype and from three GII.4 genotype variants, GII.4-1999, GII.4-2004 and GII.4-2006b, to bind to porcine gastric mucin (PGM), human saliva and differentiated human intestinal Caco-2 cells (D-Caco-2 cells).

Results

Distinct patterns of saliva binding with the NoV GII.4 variant VLPs were observed, although they bound to D-Caco-2 cells independently of the expression of HBGAs. Monoclonal antibodies against Lewis antigens were able to block the binding of NoV VLPs to saliva, but not to D-Caco-2 cells. Blocking HBGAs on the surface of D-Caco-2 cells with specific monoclonal antibodies did not affect NoV VLP binding to cellular membranes. Co-localisation of Lewis y (Le^y) and H-type 2 antigens with NoV VLPs was not observed by immunofluorescence assays.

Conclusion

Although the binding of NoV VLPs of GII.4 genotype variants to human saliva samples occur with distinct HBGA binding patterns and can be blocked by antibodies against Lewis antigens, their attachment to D-Caco-2 cells can be mediated by other receptors, which still need further investigation.

Early Detection of Epidemic GII-4 Norovirus Strains in UK and Malawi: Role of Surveillance of Sporadic Acute Gastroenteritis in Anticipating Global Epidemics

Noroviruses are endemic in the human population, and are recognised as a leading cause of acute gastroenteritis worldwide. Although they are a highly diverse group of viruses, genogroup-II genotype-4 (GII-4) noroviruses are the most frequently identified strains worldwide. The predominance of GII-4 norovirus strains is driven by the periodic emergence of antigenic variants capable of evading herd protection. The global molecular epidemiology of emerging GII-4 strains is largely based on data from outbreak surveillance programmes, but the epidemiology of GII-4 strains among sporadic or community cases is far less well studied. To understand the distribution of GII-4 norovirus strains associated with gastroenteritis in the wider population, we characterised the GII-4 norovirus strains detected during studies of sporadic cases of infectious gastroenteritis collected in the UK and Malawi between 1993 and 2009. Our data shows that GII-4 norovirus strains that have emerged as strains of global epidemic importance have circulated in the community up to 18 years before their recognition as pandemic strains associated with increases in outbreaks. These data may suggest that more comprehensive surveillance programmes that incorporate strains associated with sporadic cases may provide a way for early detection of emerging strains with pandemic potential. This may be of particular relevance as vaccines become available.

Upright Time and Sit-To-Stand Transition Progression After Total Hip Arthroplasty: An Inhospital Longitudinal Study

BACKGROUND

Although early mobilization in hospital is a key element of post-total hip arthroplasty rehabilitation, it is poorly documented.

METHODS

To gain quantitative insight into inhospital mobilization, upright times and sit-to-stand transitions (STS) were measured using a thigh-mounted movement sensor in 44 participants (13 males and 31 females), age 50 to 82 years, in an observational, postsurgery, inhospital, longitudinal study.

RESULTS

Some participants performed no activity in the first 24 hours after surgery. However, in the last 24 hours before discharge, participants performed a median of 40 (interquartile range [IQR], 15) STS and spent 134 minutes (IQR, 74 minutes) upright. Activity in rehabilitation constituted 19.4% (IQR, 15.8%) of STS and 13.3% (IQR, 5.5%) of upright time. Females spent longer in hospital (80 hours; IQR, 24) compared to males (54 hours; IQR, 26).

CONCLUSION

Although there was considerable activity within rehabilitation periods, a large majority of STS and upright time occurred outside rehabilitation. Within the last 24 hours in hospital, all participants were upright for prolonged periods and completed numerous STS.

Early impact of rotavirus vaccination in a large paediatric hospital in the UK

The impact of routine rotavirus vaccination on community-acquired (CA) and healthcare-associated (HA) rotavirus gastroenteritis (RVGE) at a large paediatric hospital, UK, was investigated over a 13-year period. A total of 1644 hospitalized children aged 0-15 years tested positive for rotavirus between July 2002 and June 2015. Interrupted time-series analysis demonstrated that, post vaccine introduction (July 2013 to June 2015), CA- and HA-RVGE hospitalizations were 83% [95% confidence interval (CI): 72-90%) and 83% (95% CI: 66-92%] lower than expected, respectively. Rotavirus vaccination has rapidly reduced the hospital rotavirus disease burden among both CA- and HA-RVGE cases.

Rapid Declines in Age Group-Specific Rotavirus Infection and Acute Gastroenteritis Among Vaccinated and Unvaccinated Individuals Within 1 Year of Rotavirus Vaccine Introduction in England and Wales

BACKGROUND

The oral infant rotavirus vaccine, Rotarix, was introduced in England and Wales in July 2013. We estimated the impact on laboratory-confirmed rotavirus infections and hospitalizations for all-cause acute gastroenteritis (AGE) during the first year after introduction.

METHODS

We extracted data on laboratory-confirmed rotavirus infections (July 2000 through June 2015) and all-cause AGE-associated hospitalizations (July 2007 through June 2014) for all age groups using national databases (LabBase2 and HES). We determined the ratio of the rate during the 2013-2014 rotavirus season to the rate during the prevaccination era.

RESULTS

In infants, there was a 77% decline (rate ratio [RR], 0.23; 95% confidence interval [CI], .16-.32) in laboratory-confirmed rotavirus infections and a 26% decline (RR, 0.74; 95% CI, .65-.84) in all-cause AGE-associated hospitalizations in 2013-2014, compared with the prevaccination era. Large reductions were also observed in older children, adults, and older adults. We estimated that 10 884 laboratory-confirmed infections and 50 427 all-cause AGE-associated hospital admissions were averted in 2013-2014. Similar reductions have been observed for laboratory-confirmed rotavirus infections during the 2014-2015 season.

CONCLUSIONS

The rapid declines in rotavirus infection and AGE in vaccinated and unvaccinated age groups within 1 year of introducing an infant rotavirus vaccination program are far greater than expected and than previously reported by other countries.

Emergence of the GII-4 Norovirus Sydney2012 strain in England, winter 2012-2013

Norovirus is the commonest cause of acute gastrointestinal disease and is the main aetiological agent of outbreaks of gastroenteritis, particularly in semi-closed environments. Norovirus infections in England typically peak between December and March each year. The most commonly detected norovirus strains belong to the genetically diverse genogroup-II genotype-4 (GII-4) genocluster and in the previous two norovirus winter seasons the majority of GII-4 strains in circulation worldwide have been genetically similar to the GII-4 strain New Orleans 1805/2009/USA. At the beginning of the 2012/13 season a genetically distinct GII-4 strain (Sydney 2012/NSW0514/2012/AU) was described which emerged worldwide during the winter of 2012/13. Here we describe the emergence of norovirus strains genetically related to Sydney2012 in England during the 2012/13 season to replace NewOrleans2009 strains as the most commonly detected variant of GII-4 norovirus in England. Furthermore, we demonstrate that whilst the emergence of Sydney2012 coincided with an early peak in the number of norovirus outbreaks, there was not an overall increase in norovirus activity compared to the previous season. Finally, we show that the Sydney2012 strain is associated with distinct genetic changes compared to the NewOrleans2009 strain, and these changes may have contributed to the emergence of the Sydney2012 strain.

The gammaretroviral p12 protein has multiple domains that function during the early stages of replication

Background

The Moloney murine leukaemia virus (Mo-MLV) gag gene encodes three main structural proteins, matrix, capsid and nucleocapsid and a protein called p12. In addition to its role during the late stages of infection, p12 has an essential, but undefined, function during early post-entry events. As these stages of retroviral infection remain poorly understood, we set out to investigate the function of p12.

Results

Examination of the infectivity of Mo-MLV virus-like particles containing a mixture of wild type and mutant p12 revealed that the N- and C-terminal regions of p12 are sequentially acting domains, both required for p12 function, and that the N-terminal activity precedes the C-terminal activity in the viral life cycle. By creating a panel of p12 mutants in other gammaretroviruses, we showed that these domains are conserved in this retroviral genus. We also undertook a detailed mutational analysis of each domain, identifying residues essential for function. These data show that different regions of the N-terminal domain are necessary for infectivity in different gammaretroviruses, in stark contrast to the C-terminal domain where the same region is essential for all viruses. Moreover, chimeras between the p12 proteins of Mo-MLV and gibbon ape leukaemia virus revealed that the C-terminal domains are interchangeable whereas the N-terminal domains are not. Finally, we identified potential functions for each domain. We observed that particles with defects in the N-terminus of p12 were unable to abrogate restriction factors, implying that their cores were impaired. We further showed that defects in the C-terminal domain of p12 could be overcome by introducing a chromatin binding motif into the protein.

Conclusions

Based on these data, we propose a model for p12 function where the N-terminus of p12 interacts with, and stabilizes, the viral core, allowing the C-terminus of p12 to tether the preintegration complex to host chromatin during mitosis, facilitating integration.

Molecular evolution of GII-4 Norovirus strains

BACKGROUND

Human Noroviruses (NoV) are the major cause of acute nonbacterial gastroenteritis and the leading cause of outbreaks of gastroenteritis worldwide. Genotype II-4 (GII-4) NoV has been shown to spread rapidly and is the most commonly detected strain worldwide, particularly in association with outbreaks. Previously, we have shown that circulating GII-4 NoV strains exist as populations of selectively neutral variants, and that the emergence of epidemic GII-4 NoV strains correlated with mutations in at least two key sites (Sites A and B) within the P2 domain of the surface exposed major capsid protein (VP1).

METHODOLOGY

We developed a rapid pyrosequencing method for screening of the two Sites A and B and a homology based modelling system was used to predict the effects of amino acid substitutions at these sites on the antigenic properties of the virus (defined as surface motif types).

PRINCIPLE FINDING/CONCLUSION

Here, we describe the characterisation of amino acid diversity at Sites A and B for 1062 GII-4 NoV strains from clinical specimen associated with outbreak of gastroenteritis (2000-2011) and 250 GII-4 NoV sequences from Genbank. Our data identified a high diversity of different Site A and B site combinations at amino acid level and amino acid diversity was higher at Site B than Site A. Site A motifs could be grouped into 3 clusters based on similar surface motif types. We predict that Site A is a major epitope on the virus surface, responsible for defining the antigenic profile, and a more subtle role for Site B, maintaining minor antigenic variation within the virus population.

Human bocaviruses are not significantly associated with gastroenteritis: results of retesting archive DNA from a case control study in the UK

Gastroenteritis is a common illness causing considerable morbidity and mortality worldwide. Despite improvements in detection methods, a significant diagnostic gap still remains. Human bocavirus (HBoV)s, which are associated with respiratory infections, have also frequently been detected in stool samples in cases of gastroenteritis, and a tentative association between HBoVs, and in particular type-2 HBoVs, and gastroenteritis has previously been made. The aim of this study was to determine the role of HBoVs in gastroenteritis, using archived DNA samples from the case-control Infectious Intestinal Disease Study (IID). DNA extracted from stool samples from 2,256 cases and 2,124 controls were tested for the presence of HBoV DNA. All samples were screened in a real time PCR pan-HBoV assay, and positive samples were then tested in genotype 1 to 3-specific assays. HBoV was detected in 7.4% but no significantly different prevalence was observed between cases and controls. In the genotype-specific assays 106 of the 324 HBoV-positive samples were genotyped, with HBoV-1 predominantly found in controls whilst HBoV-2 was more frequently associated with cases of gastroenteritis (p<0.01). A significant proportion of HBoV positives could not be typed using the type specific assays, 67% of the total positives, and this was most likely due to low viral loads being present in the samples. However, the distribution of the untyped HBoV strains was no different between cases and controls. In conclusion, HBoVs, including HBoV-2 do not appear to be a significant cause of gastroenteritis in the UK population.

Norovirus: changing epidemiology, changing virology. The challenges for infection control

Norovirus infection is the commonest cause of outbreaks and sporadic cases of acute gastrointestinal disease in England and Wales. It is estimated that 4.5% of the population are infected by norovirus each year. Some years see more infections than others and occasionally peaks of summer time activity can occur. Current surveillance of norovirus is based on two main sources of information, routine laboratory reporting and reports of norovirus outbreaks. There are still significant barriers impeding a better understanding of the biology and epidemiology of noroviruses. Modern genetic techniques have shed light on ways in which the virus interacts with its host and evades the immune system. Some of these techniques have also led to new tools that may be useful in tracking outbreaks of norovirus, and in turn, to study the effect of potential intervention strategies, aimed at preventing or curtailing transmission within outbreaks.

The impact of conservation on the status of the world's vertebrates

Using data for 25,780 species categorized on the International Union for Conservation of Nature Red List, we present an assessment of the status of the world's vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: On average, 52 species of mammals, birds, and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth again as much in the absence of these. Nonetheless, current conservation efforts remain insufficient to offset the main drivers of biodiversity loss in these groups: agricultural expansion, logging, overexploitation, and invasive alien species.

Characterisation of a GII-4 norovirus variant-specific surface-exposed site involved in antibody binding

Background

The human noroviruses are a highly diverse group of viruses with a single-stranded RNA genome encoding a single major structural protein (VP1), which has a hypervariable domain (P2 domain) as the most exposed part of the virion. The noroviruses are classified on the basis of nucleotide sequence diversity in the VP1-encoding ORF2 gene, which divides the majority of human noroviruses into two genogroups (GI and GII). GII-4 noroviruses are the major aetiological agent of outbreaks of gastroenteritis around the world. During a winter season the diversity among the GII-4 noroviruses has been shown to fluctuate, driving the appearance of new virus variants in the population. We have previously shown that sequence data and in silico modelling experiments suggest there are two surface-exposed sites (site A and site B) in the hypervariable P2 domain. We predict these sites may form a functional variant-specific epitope that evolves under selective pressure from the host immune response and gives rise to antibody escape mutants.

Results

In this paper, we describe the construction of recombinant baculoviruses to express VLPs representing one pre-epidemic and one epidemic variant of GII-4 noroviruses, and the production of monoclonal antibodies against them. We use these novel reagents to provide evidence that site A and site B form a conformational, variant-specific, surface-exposed site on the GII-4 norovirus capsid that is involved in antibody binding.

Conclusion

As predicted by our earlier study, significant amino acid changes at site A and site B give rise to GII-4 norovirus epidemic variants that are antibody escape mutants.

Mitochondrial control of platelet apoptosis: effect of cyclosporin A, an inhibitor of the mitochondrial permeability transition pore

The role of the mitochondrial permeability transition pore (MPTP) in apoptosis of nucleated cells is well documented. In contrast, the role of MPTP in apoptosis of anucleated platelets is largely unknown. The aim of this study was to elucidate the contribution of MPTP in the control of different manifestations of platelet apoptosis by analyzing the effect of cyclosporin A (CsA), a potent inhibitor of MPTP formation. Using flow cytometry, we studied the effect of pretreatment of platelets with CsA on apoptotic responses in human platelets stimulated with calcium ionophore A23187. We found that CsA inhibited A23187-stimulated platelet apoptosis, completely preventing (i) depolarization of mitochondrial inner membrane potential (DeltaPsim), (ii) activation of cytosolic apoptosis executioner caspase-3, (iii) platelet shrinkage, and (iv) fragmentation of platelets to microparticles, but (v) only partially (approximately 25%), inhibiting phosphatidylserine (PS) exposure on the platelet surface. This study shows that MPTP formation is upstream of DeltaPsim depolarization, caspase-3 activation, platelet shrinkage and microparticle formation, and stringently controls these apoptotic events in A23187-stimulated platelets but is less involved in PS externalization. These data also indicate that CsA may rescue platelets from apoptosis, preventing caspase-3 activation and inhibiting the terminal cellular manifestations of platelet apoptosis, such as platelet shrinkage and degradation to microparticles. Furthermore, the results suggest a novel potentially useful application of CsA as an inhibitor of platelet demise through apoptosis in thrombocytopenias associated with enhanced platelet apoptosis.

The young adult with hip impingement: deciding on the optimal intervention

Femoroacetabular impingement is a recognized cause of hip pain and osteoarthritis in young adults. The clinical presentation of this pathology is quite varied in terms of the underlying deformity, patient age, and the degree of cartilage damage. Open hip surgery with surgical dislocation is the gold standard for treating femoral deformities and the damaged acetabular labral complex; however, less invasive techniques such as hip arthroscopy and arthroscopy combined with limited anterior hip arthrotomy may provide comparable outcomes with less surgical morbidity. Unresolved issues include the indications for acetabular rim trimming with labral refixation in the presence of acetabular retroversion and/or delaminated acetabular cartilage. Other issues involve the use of arthroplasty in older patients and/or in those with significant cartilage damage.