Monitoring the progress towards the elimination of hepatitis B and C in Sweden: estimation of core indicators for 2015 and 2018.

INTRODUCTION: To monitor Sweden's progress towards the WHO goal of eliminating viral hepatitis, we estimated the prevalence, notification rate, and liver-related morbidity and mortality for diagnosed hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in 2015 and 2018. METHODS: We identified cases of hepatitis B and C within the National System for Notifiable Diseases and obtained data on treatment and whether the case was deceased or not. We calculated prevalence, notification rates per 100,000, and proportion of newly diagnosed cases of hepatitis with liver disease at the time of diagnosis, and proportion of all deceased cases who died from liver disease. We calculated Poisson 95% confidence intervals (CIs) around the notification rates and Wilson 95% CIs around prevalence and mortality estimates. RESULTS: In 2015 and 2018, the prevalence of diagnosed HBV infections was 0.20% [95% CI: 0.19-0.20] and 0.21% [0.20-0.21]. Notification rates per 100,000 for HBV infections were 13.02 [12.32-13.76] and 7.71 [7.18-8.27]. HBV liver-related morbidity was 2.65% [1.90-3.68] and 2.16% [1.35-3.43]. HBV liver-related mortality was 20.00% [14.81-26.44] and 17.95% [13.20-23.94]. In 2015 and 2018, the prevalence of diagnosed HCV-infections was 0.24% [0.24-0.25] and 0.18% [0.18-0.19]. Notification rates per 100,000 for HCV infections were 15.92 [15.14-16.73] and 13.05 [12.36-13.77]. HCV liver-related morbidity was 8.14% [6.89-9.60] and 3.90% [2.99-5.08]. HCV liver-related mortality was 27.08% [24.54-29.77] and 26.90% [24.12-29.88]. CONCLUSIONS: All indicators decreased or remained stable between 2015 and 2018, indicating progress in the elimination of viral hepatitis, especially for HCV infection.

Hepatitis B virus elimination status and strategies in circumpolar countries, 2020.

Hepatitis B virus (HBV) infection remains a global health threat. The World Health Organization (WHO) established a goal to eliminate HBV infection as a public health threat by 2030, and defined targets for key interventions to achieve that goal. We evaluated HBV burden and relevant national recommendations for progress towards WHO targets in circumpolar countries. Viral hepatitis experts of circumpolar countries were surveyed regarding their country's burden of HBV, achievement of WHO targets and national public health authority recommendations for HBV prevention and control. Eight of nine circumpolar countries responded. All countries continue to see new HBV infections. Data about HBV prevalence and progress in reaching WHO 2030 elimination targets are lacking. No country was able to report data for all seven WHO target measures. All countries have recommendations targeting the prevention of mother-to-child transmission. Only the USA and Greenland recommend universal birth dose vaccination. Four countries have recommendations to screen persons at high risk for HBV. Existing recommendations largely address prevention; however, recommendations for universal birth dose vaccination have not been widely introduced. Opportunities remain for the development of trackable targets and national elimination planning to screen and treat for HBV to reduce incidence and mortality.

High impact of molecular surveillance on hepatitis A outbreak case detection in Sweden: a retrospective study, 2009 to 2018.

BackgroundSwedish hepatitis A surveillance includes sequence-based typing, but its contribution to outbreak detection in relation to epidemiological investigations has not been fully evaluated.AimTo evaluate the role of sequence-based typing in hepatitis A outbreak detection and to describe the hepatitis A epidemiology in Sweden to improve surveillance.MethodsWe retrospectively investigated hepatitis A virus sequences of 447 cases notified in Sweden 2009-18. We performed a phylogenetic analysis of evolutionary distances to identify cases with similar virus sequences (≥ 459/460 identical nt in the VP1/P2A junction). Unique sequences, dyads and sequence-based clusters (SBCs) were identified. We linked non-sequenced cases by epidemiological information and retrospectively assessed the value of typing for outbreak identification.ResultsFifty-five percent (n = 542/990) of the notified hepatitis A cases were referred to the Public Health Agency of Sweden for typing and 447 (45%) were sequenced successfully. Subgenotypes included IA (42.5%, n = 190), IB (42.7%, n = 191) and IIIA (14.8%, n = 66). Phylogenetic analysis identified 154 unique sequences, 33 dyads (66 cases) and 34 SBCs (227 cases). The combination of molecular and epidemiological data revealed 23 potential outbreaks comprising 201 cases. Cases were linked by sequence (59%, n = 118), epidemiological data (11%, n = 23) or both (30%, n = 60). Typing was needed to identify 15 of 23 potential outbreak signals.ConclusionSequence-based typing contributed substantially to detecting clustering cases and identifying outbreaks in Sweden. The results show routine sequence-based typing detects outbreaks, promotes timely outbreak investigations and facilitates international collaboration.

Improving preparedness to respond to cross-border hepatitis A outbreaks in the European Union/European Economic Area: towards comparable sequencing of hepatitis A virus.

IntroductionSequence-based typing of hepatitis A virus (HAV) is important for outbreak detection, investigation and surveillance. In 2013, sequencing was central to resolving a large European Union (EU)-wide outbreak related to frozen berries. However, as the sequenced HAV genome regions were only partly comparable between countries, results were not always conclusive.AimThe objective was to gather information on HAV surveillance and sequencing in EU/European Economic Area (EEA) countries to find ways to harmonise their procedures, for improvement of cross-border outbreak responses.MethodsIn 2014, the European Centre for Disease Prevention and Control (ECDC) conducted a survey on HAV surveillance practices in EU/EEA countries. The survey enquired whether a referral system for confirming primary diagnostics of hepatitis A existed as well as a central collection/storage of hepatitis A cases' samples for typing. Questions on HAV sequencing procedures were also asked. Based on the results, an expert consultation proposed harmonised procedures for cross-border outbreak response, in particular regarding sequencing. In 2016, a follow-up survey assessed uptake of suggested methods.ResultsOf 31 EU/EEA countries, 23 (2014) and 27 (2016) participated. Numbers of countries with central collection and storage of HAV positive samples and of those performing sequencing increased from 12 to 15 and 12 to 14 respectively in 2016, with all countries typing an overlapping fragment of 218 nt. However, variation existed in the sequenced genomic regions and their lengths.ConclusionsWhile HAV sequences in EU/EEA countries are comparable for surveillance, collaboration in sharing and comparing these can be further strengthened.

Hepatitis A outbreak linked to imported frozen strawberries by sequencing, Sweden and Austria, June to September 2018.

Between June-September 2018, 20 hepatitis A cases were notified in six counties in Sweden. Combined epidemiological and microbiological investigations identified imported frozen strawberries produced in Poland as the source of the outbreak. Sequence analysis confirmed the outbreak strain IB in the strawberries with 100 % identity and the respective batch was withdrawn. Sharing the sequence information internationally led to the identification of 14 additional cases in Austria, linked to strawberries from the same producer.

Summary of available surveillance data on hepatitis C virus infection from eight Arctic countries, 2012 to 2014.

We summarised available hepatitis C virus (HCV) surveillance data for 2012-14 from Arctic/sub-Arctic countries/regions. We sent a HCV data collection template by email to public health authorities in all jurisdictions. Population statistics obtained from census sources for each country were used to estimate rates of reported acute and chronic/undifferentiated HCV cases. Seven countries with Arctic regions (Canada, Denmark, Finland, Greenland, Norway, Sweden and the United States, represented by the state of Alaska), including three Canadian territories and one province, as well as 11 Russian subnational Arctic regions, completed the data collection template. Data on acute HCV infection during 2014 was available from three Arctic countries and all Russian Arctic regions (rate range 0/100,000 population in Greenland, as well as Nenets and Chukotka Automous Okrugs (Russian subnational Arctic regions) to 3.7/100,000 in the Russian Republic of Komi). The rate of people with chronic/undifferentiated HCV infection in 2014 ranged from 0/100,000 in Greenland to 171.2/100,000 in Alaska. In most countries/regions, the majority of HCV-infected people were male and aged 19-64 years. Differences in surveillance methods preclude direct comparisons of HCV surveillance data between Arctic countries/regions. Our data can inform future efforts to develop standardised approaches to HCV surveillance in the Arctic countries/regions by identifying similarities/differences between the surveillance data collected.

Hepatitis A outbreak disproportionately affecting men who have sex with men (MSM) in the European Union and European Economic Area, June 2016 to May 2017.

Between 1 June 2016 and 31 May 2017, 17 European Union (EU) and European Economic Area countries reported 4,096 cases associated with a multi-country hepatitis A (HA) outbreak. Molecular analysis identified three co-circulating hepatitis A virus (HAV) strains of genotype IA: VRD_521_2016, V16-25801 and RIVM-HAV16-090. We categorised cases as confirmed, probable or possible, according to the EU outbreak case definitions. Confirmed cases were infected with one of the three outbreak strains. We investigated case characteristics and strain-specific risk factors for transmission. A total of 1,400 (34%) cases were confirmed; VRD_521_2016 and RIVM-HAV16-090 accounted for 92% of these. Among confirmed cases with available epidemiological data, 92% (361/393) were unvaccinated, 43% (83/195) travelled to Spain during the incubation period and 84% (565/676) identified as men who have sex with men (MSM). Results depict an HA outbreak of multiple HAV strains, within a cross-European population, that was particularly driven by transmission between non-immune MSM engaging in high-risk sexual behaviour. The most effective preventive measure to curb this outbreak is HAV vaccination of MSM, supplemented by primary prevention campaigns that target the MSM population and promote protective sexual behaviour.

Two concurrent outbreaks of hepatitis A highlight the risk of infection for non-immune travellers to Morocco, January to June 2018.

From January to June 2018, two ongoing hepatitis A outbreaks affected travellers returning from Morocco and cases in Europe without travel history, resulting in 163 patients in eight European countries. Most interviewed travel-related cases were unaware of the hepatitis A risk in Morocco. Molecular analysis revealed two distinct hepatitis A virus (HAV) strains (subgenotype IA DK2018_231; subgenotype IB V18-16428). Vaccination recommendations should be emphasised to increase awareness among non-immune travellers to Morocco and HAV-endemic countries.

Molecular characterization of HCV in a Swedish county over 8 years (2002-2009) reveals distinct transmission patterns.

BACKGROUND: Hepatitis C virus (HCV) is a major public health concern and data on its molecular epidemiology in Sweden is scarce. We carried out an 8-year population-based study of newly diagnosed HCV cases in one of Sweden's centrally situated counties, Södermanland (D-county). The aim was to characterize the HCV strains circulating, analyze their genetic relatedness to detect networks, and in combination with demographic data learn more about transmission. METHODS: Molecular analyses of serum samples from 91% (N=557) of all newly notified cases in D-county, 2002-2009, were performed. Phylogenetic analysis (NS5B gene, 300 bp) was linked to demographic data from the national surveillance database, SmiNet, to characterize D-county transmission clusters. The linear-by-linear association test (LBL) was used to analyze trends over time. RESULTS: The most prevalent subtypes were 1a (38%) and 3a (34%). Subtype 1a was most prevalent among cases transmitted via sexual contact, via contaminated blood, or blood products, while subtype 3a was most prevalent among people who inject drugs (PWIDs). Phylogenetic analysis revealed that the subtype 3a sequences formed more and larger transmission clusters (50% of the sequences clustered), while the 1a sequences formed smaller clusters (19% of the sequences clustered), possibly suggesting different epidemics. CONCLUSION: We found different transmission patterns in D-county which may, from a public health perspective, have implications for how to control virus infections by targeted interventions.

Bacterial ribosome requires multiple L12 dimers for efficient initiation and elongation of protein synthesis involving IF2 and EF-G.

The ribosomal stalk in bacteria is composed of four or six copies of L12 proteins arranged in dimers that bind to the adjacent sites on protein L10, spanning 10 amino acids each from the L10 C-terminus. To study why multiple L12 dimers are required on the ribosome, we created a chromosomally engineered Escherichia coli strain, JE105, in which the peripheral L12 dimer binding site was deleted. Thus JE105 harbors ribosomes with only a single L12 dimer. Compared to MG1655, the parental strain with two L12 dimers, JE105 showed significant growth defect suggesting suboptimal function of the ribosomes with one L12 dimer. When tested in a cell-free reconstituted transcription-translation assay the synthesis of a full-length protein, firefly luciferase, was notably slower with JE105 70S ribosomes and 50S subunits. Further, in vitro analysis by fast kinetics revealed that single L12 dimer ribosomes from JE105 are defective in two major steps of translation, namely initiation and elongation involving translational GTPases IF2 and EF-G. Varying number of L12 dimers on the ribosome can be a mechanism in bacteria for modulating the rate of translation in response to growth condition.

A single-step method for purification of active His-tagged ribosomes from a genetically engineered Escherichia coli.

With the rapid development of the ribosome field in recent years a quick, simple and high-throughput method for purification of the bacterial ribosome is in demand. We have designed a new strain of Escherichia coli (JE28) by an in-frame fusion of a nucleotide sequence encoding a hexa-histidine affinity tag at the 3'-end of the single copy rplL gene (encoding the ribosomal protein L12) at the chromosomal site of the wild-type strain MG1655. As a result, JE28 produces a homogeneous population of ribosomes (His)(6)-tagged at the C-termini of all four L12 proteins. Furthermore, we have developed a single-step, high-throughput method for purification of tetra-(His)(6)-tagged 70S ribosomes from this strain using affinity chromatography. These ribosomes, when compared with the conventionally purified ones in sucrose gradient centrifugation, 2D-gel, dipeptide formation and a full-length protein synthesis assay showed higher yield and activity. We further describe how this method can be adapted for purification of ribosomal subunits and mutant ribosomes. These methodologies could, in principle, also be used to purify any functional multimeric complex from the bacterial cell.

Functional interplay between the jaw domain of bacterial RNA polymerase and allele-specific residues in the product RNA-binding pocket.

Bacterial RNA polymerase (RNAP) is a complex molecular machine in which the network of interacting parts and their movements, including contacts to nascent RNA and the DNA template, are at best partially understood. The jaw domain is a part of RNAP that makes a key contact to duplex DNA as it enters the enzyme from downstream and also contacts two other parts of RNAP, the trigger loop, which lies in the RNAP secondary channel, and a sequence insertion in the Escherichia coli RNAP trigger loop that forms an external domain and also contacts downstream DNA. Deletion of the jaw domain causes defects in transcriptional pausing and in bacterial growth. We report here that these defects can be partially corrected by a limited set of substitutions in a distant part of RNAP, the product RNA-binding pocket. The product RNA-binding pocket binds nascent RNA upstream of the active site and is the binding site for the RNAP inhibitor rifampicin when RNA is absent. These substitutions have little effect on transcript elongation between pause sites and actually exacerbate jaw-deletion defects in transcription initiation, suggesting that the pausing defects may be principally responsible for the in vivo phenotype of the jaw deletion. We suggest that the counteracting effects on pausing of the alterations in the jaw and the product RNA binding site may be mediated either by effects on translocation or via allosteric communication to the RNAP active site.

The downstream DNA jaw of bacterial RNA polymerase facilitates both transcriptional initiation and pausing.

Regulation of RNA polymerase during initiation, elongation, and termination of transcription is mediated in part by interactions with intrinsic regulatory signals encoded in the RNA and DNA that contact the enzyme. These interactions include contacts to an 8-9-bp RNA:DNA hybrid within the active-site cleft of the enzyme, contacts to the melted nontemplate DNA strand in the vicinity of the hybrid, contacts to exiting RNA upstream of the hybrid, and contacts to approximately 20 bp of duplex DNA downstream of the active site. Based on characterization of an amino acid substitution (G1161R) and a deletion (Delta1149-1190) in the jaw domain of the bacterial RNA polymerase largest subunit (beta'), we report here that contacts of the jaw domain to downstream DNA at the leading edge of the transcription complex contribute to regulation during all three phases of transcription. The results provide insight into the role of the jaw domain-downstream DNA contact in transcriptional initiation and pausing and suggest possible explanations for the previously reported isolation of the jaw mutants based on reduced ColEI plasmid replication.