Genomic epidemiology of the main SARS-CoV-2 variants in Italy between summer 2020 and winter 2021.

Since the beginning of the pandemic, SARS-CoV-2 has shown a great genomic variability, resulting in the continuous emergence of new variants that has made their global monitoring and study a priority. This work aimed to study the genomic heterogeneity, the temporal origin, the rate of viral evolution and the population dynamics of the main circulating variants (20E.EU1, Alpha and Delta) in Italy, in August 2020-January 2022 period. For phylogenetic analyses, three datasets were set up, each for a different main lineage/variant circulating in Italy in that time including other Italian and International sequences of the same lineage/variant, available in GISAID sampled in the same times. The international dataset showed 26 (23% Italians, 23% singleton, 54% mixed), 40 (60% mixed, 37.5% Italians, 1 singleton) and 42 (85.7% mixed, 9.5% singleton, 4.8% Italians) clusters with at least one Italian sequence, in 20E.EU1  clade, Alpha and Delta variants, respectively. The estimation of tMRCAs in the Italian clusters (including >70% of genomes from Italy) showed that in all the lineage/variant, the earliest clusters were the largest in size and the most persistent in time and frequently mixed. Isolates from the major Italian Islands tended to segregate in clusters more frequently than those from other part of Italy. The study of infection dynamics showed a positive correlation between the trend in the effective number of infections estimated by BSP model and the Re curves estimated by birth-death skyline plot. The present work highlighted different evolutionary dynamics of studied lineages with high concordance between epidemiological parameters estimation and phylodynamic trends suggesting that the mechanism of replacement of the SARS-CoV-2 variants must be related to a complex of factors involving the transmissibility, as well as the implementation of control measures, and the level of cross-immunization within the population.

Genomic epidemiology and phylogenetics applied to the study of SARS-CoV-2 pandemic.

The study of characteristics, prevalence and patterns of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is significant to monitor and define the status of the pandemic, helping to design and evaluate control strategies. In this setting, the continuous emergence of new variants and their dynamic of replacement underline the importance of implementing genomic epidemiology and phylogenetic methods for the molecular monitoring and surveillance of this new virus. The current profile of the pandemic can change rapidly when new variants emerge and spread, impacting epidemiology and public health in terms of prevention and treatment and making it necessary to develop new molecules and formulate vaccines. In this paper, we reviewed and synthesized the main studies on molecular genomics and phylogeny of SARS-CoV-2 during the pandemic, and highlighted their contributions to our understanding of this new emergent pathogen.

Performance of the COVID19SEROSpeed IgM/IgG Rapid Test, an Immunochromatographic Assay for the Diagnosis of SARS-CoV-2 Infection: a Multicenter European Study.

This study assessed the diagnostic performance of the new COVID19SEROSpeed IgM/IgG rapid test (BioSpeedia, a spinoff of the Pasteur Institute of Paris) for the detection of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in comparison to other commercial antibody assays through a large cross-European investigation. The clinical specificity was assessed on 215 prepandemic sera (including some from patients with viral infections or autoimmune disorders). The clinical sensitivity was evaluated on 710 sera from 564 patients whose SARS-CoV-2 infection was confirmed by quantitative reverse transcription-PCR (qRT-PCR) and whose antibody response was compared to that measured by five other commercial tests. The kinetics of the antibody response were also analyzed in seven symptomatic patients. The specificity of the test (BioS) on prepandemic specimens was 98.1% (95% confidence interval [CI], 96.2% to 99.4%). When tested on the 710 pandemic specimens, BioS showed an overall clinical sensitivity of 86.0% (95% CI, 0.83 to 0.89), with good concordance with the Euroimmun assay (overall concordance of 0.91; Cohen's kappa coefficient of 0.62). Due in part to simultaneous detection of IgM and IgG for both S1 and N proteins, BioS exhibited the highest positive percent agreement at ≥11 days post-symptom onset (PSO). In conclusion, the BioS IgM/IgG rapid test was highly specific and demonstrated a higher positive percentage of agreement than all the enzyme-linked immunosorbent assay/chemiluminescence immunoassay (ELISA/CLIA) commercial tests considered in this study. Moreover, by detecting the presence of antibodies prior to 11 days PSO in 78.2% of the patients, the BioS test increased the efficiency of the diagnosis of SARS-CoV-2 infection in the early stages of the disease.

Circulating SARS-CoV-2 variants in Italy, October 2020-March 2021.

A growing number of emerging SARS-CoV-2 variants is being identified worldwide, potentially impacting the effectiveness of current vaccines. We report the data obtained in several Italian regions involved in the SARS-CoV-2 variant monitoring from the beginning of the epidemic and spanning the period from October 2020 to March 2021.

Sofosbuvir Selects for Drug-Resistant Amino Acid Variants in the Zika Virus RNA-Dependent RNA-Polymerase Complex In Vitro.

The nucleotide analog sofosbuvir, licensed for the treatment of hepatitis C, recently revealed activity against the Zika virus (ZIKV) in vitro and in animal models. However, the ZIKV genetic barrier to sofosbuvir has not yet been characterized. In this study, in vitro selection experiments were performed in infected human hepatoma cell lines. Increasing drug pressure significantly delayed viral breakthrough (p = 0.029). A double mutant in the NS5 gene (V360L/V607I) emerged in 3 independent experiments at 40-80 µM sofosbuvir resulting in a 3.9 ± 0.9-fold half- maximal inhibitory concentration (IC50) shift with respect to the wild type (WT) virus. A triple mutant (C269Y/V360L/V607I), detected in one experiment at 80 µM, conferred a 6.8-fold IC50 shift with respect to the WT. Molecular dynamics simulations confirmed that the double mutant V360L/V607I impacts the binding mode of sofosbuvir, supporting its role in sofosbuvir resistance. Due to the distance from the catalytic site and to the lack of reliable structural data, the contribution of C269Y was not investigated in silico. By a combination of sequence analysis, phenotypic susceptibility testing, and molecular modeling, we characterized a double ZIKV NS5 mutant with decreased sofosbuvir susceptibility. These data add important information to the profile of sofosbuvir as a possible lead for anti-ZIKV drug development.

Early phylogenetic estimate of the effective reproduction number of SARS-CoV-2.

To reconstruct the evolutionary dynamics of the 2019 novel-coronavirus recently causing an outbreak in Wuhan, China, 52 SARS-CoV-2 genomes available on 4 February 2020 at Global Initiative on Sharing All Influenza Data were analyzed. The two models used to estimate the reproduction number (coalescent-based exponential growth and a birth-death skyline method) indicated an estimated mean evolutionary rate of 7.8 × 10-4 subs/site/year (range, 1.1 × 10-4 -15 × 10-4 ) and a mean tMRCA of the tree root of 73 days. The estimated R value was 2.6 (range, 2.1-5.1), and increased from 0.8 to 2.4 in December 2019. The estimated mean doubling time of the epidemic was between 3.6 and 4.1 days. This study proves the usefulness of phylogeny in supporting the surveillance of emerging new infections even as the epidemic is growing.

Genomic characterization and phylogenetic analysis of SARS-COV-2 in Italy.

This report describes the isolation, molecular characterization, and phylogenetic analysis of the first three complete genomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolated from three patients involved in the first outbreak of COVID-19 in Lombardy, Italy. Early molecular epidemiological tracing suggests that SARS-CoV-2 was present in Italy weeks before the first reported cases of infection.

Contribution of transgender sex workers to the complexity of the HIV-1 epidemic in the metropolitan area of Milan.

OBJECTIVES: Transgender people are disproportionately affected by the HIV-1 epidemic. We evaluated the origin of HIV-1 variants carried by South American transgenders living in Milan by combining accurate phylogenetic methods and epidemiological data. METHODS: We collected 156 HIV-1 pol sequences obtained from transgender patients engaged in sex work (TSWs) followed between 1999 and 2015 at L. Sacco Hospital, Milan, Italy. Phylogenetic analyses were conducted by HIV-TRACE, MrBayes, MacClade and Beast programs. Reference sequences were retrieved from Los Alamos and local databases. Last negative testing or proxy data from clinical records of infected individuals were used to investigate the country of infection. RESULTS: Among South American TSWs, the most represented HIV-1 subtypes were B (70.5%), F1 (12.8%) and C (4.4%). Gene flow migrations of B subtype indicated significant fluxes from TSWs to Italians (21.3%) belonging to all risk groups (26.4% to heterosexuals (HEs), 18.9% to men who have sex with men (MSM), 15.1% to injecting drug users). The largest proportion of bidirectional fluxes were observed between Italians and TSWs (24.6%). For F1 subtype, bidirectional viral fluxes involved TSWs and Italians (7.1% and 14.3%), and a similar proportion of fluxes linked TSWs and Italian HEs or MSM (both 15.8%). Significant fluxes were detected from Italians to TSWs for subtype C involving both MSM (30%) and HEs (40%). Country of HIV-1 acquisition was identified for 72 subjects; overall, the largest proportion of patients with B subtype (73.5%) acquired HIV-1 infection in South America. CONCLUSIONS: Our results indicated that South American transgenders largely contribute to the heterogeneity of HIV-1 variants in our country. The high number of clusters based on all subtypes indicated numerous transmission chains in which TSWs were constantly intermixed with HEs and MSM. Our results strongly advocate interventions to facilitate prevention, diagnosis and HIV-1 care continuum among transgender people.

The phylogenetic approach for viral infectious disease evolution and epidemiology: An updating review.

In the last decade, the phylogenetic approach is recurrent in molecular evolutionary analysis. On 12 May, 2019, about 2 296 213 papers are found, but typing "phylogeny" or "epidemiology AND phylogeny" only 199 804 and 20 133 are retrieved, respectively. Molecular epidemiology in infectious diseases is widely used to define the source of infection as so as the ancestral relationships of individuals sampled from a population. Coalescent theory and phylogeographic analysis have had scientific application in several, recent pandemic events, and nosocomial outbreaks. Hepatitis viruses and immunodeficiency virus (human immunodeficiency virus) have been largely studied. Phylogenetic analysis has been recently applied on Polyomaviruses so as in the more recent outbreaks due to different arboviruses type as Zika and chikungunya viruses discovering the source of infection and the geographic spread. Data on sequences isolated by the microorganism are essential to apply the phylogenetic tools and research in the field of infectious disease phylodinamics is growing up. There is the need to apply molecular phylogenetic and evolutionary methods in areas out of infectious diseases, as translational genomics and personalized medicine. Lastly, the application of these tools in vaccine strategy so as in antibiotic and antiviral researchers are encouraged.

Italian consensus recommendations for the management of hepatitis C infection in patients with rheumatoid arthritis.

Objectives: The recent introduction of direct-acting antiviral agents (DAAs) which can eliminate Hepatitis C virus (HCV) had revolutionized the treatment of HCV infections also in a complex clinical setting such as the patients with rheumatoid arthritis (RA). HCV elimination is also opportune due to the availability of more efficient immunosuppressive drugs, whose effect on the course of HCV infection is largely unknown.Methods: Consensus process was endorsed by the Italian Society of Rheumatology (SIR) and the Italian Society of Infectious and Tropical Diseases (SIMIT) to review the available evidence and produce practical, hospital-wide recommendations. The consensus panel consisted of 18 infectious diseases consultants, 20 rheumatologists and one clinical epidemiologist, who used the criteria of the Oxford Centre for Evidence-based Medicine to assess the quality of the evidence and the strength of their recommendations.Results: A core-set of statements about management of patients with RA and infection by HCV have been developed to help clinicians in their clinical practice.Conclusions: A screening for HCV should be performed in all RA patients and it is mandatory before starting an immunosuppressive therapy. Finally, a DAA treatment should be considered in all HCV-infected patients.Significance and InnovationsHCV antibodies should be investigated at the time of diagnosis of RA and, in any case, before starting immunosuppressive therapy with disease-modifying antirheumatic drugs (DMARDs).HCV eradication with DAA should be attempted as soon as possible, depending on patient conditions allowing a continuous oral treatment lasting 8-12 weeksConventional and biological DMARDs are allowed in patients with HCV infection, but they should be used cautiously in presence of advanced liver disease.

Bayesian reconstruction of the evolutionary history and cross-species transition of variola virus and orthopoxviruses.

Variola virus (VARV), the causative agent of smallpox, is an exclusively human virus belonging to the genus Orthopoxvirus, which includes many other viral species covering a wide range of mammal hosts, such as vaccinia, cowpox, camelpox, taterapox, ectromelia, and monkeypox virus. The tempo and mode of evolution of Orthopoxviruses were reconstructed using a Bayesian phylodynamic framework by analysing 80 hemagglutinin sequences retrieved from public databases. Bayesian phylogeography was used to estimate their putative ancestral hosts. In order to estimate the substitution rate, the tree including all of the available Orthopoxviruses was calibrated using historical references dating the South American variola minor clade (alastrim) to between the XVI and XIX century. The mean substitution rate determined by the analysis was 6.5 × 10-6 substitutions/site/year. Based on this evolutionary estimate, the time of the most recent common ancestor of the genus Orthopoxvirus was placed at about 10 000 years before the present. Cowpox virus was the species closest to the root of the phylogenetic tree. The root of VARV circulating in the XX century was estimated to be about 700 years ago, corresponding to about 1300 AD. The divergence between West African and South American VARV went back about 500 years ago (falling approximately in the XVI century). A rodent species is the most probable ancestral host from which the ancestors of all the known Orthopoxviruses were transmitted to the other mammal host species, and each of these species represented a dead-end for each new poxvirus species, without any further inter-specific spread.

First epidemiological and phylogenetic analysis of Hepatitis B virus infection in migrants from Mali.

The armed conflict in Mali caused a migration crisis since 2012. Most Malian refugees were in Italy. In Sub-Saharan Africa, the seroprevalence of anti-HBV antibodies is particularly high. Genotype E is the most prevalent throughout a crescent covering area from Angola to Senegal, including Mali. We report 16 HBV positive individual from 136 Malian asylum seekers in order to investigate the genetic diversity of HBV in this population. Sequencing and phylogenetic analysis has been used. The HBV genotype E isolates from Mali did not cluster together but were intermixed, with the other African sequences. Only three supported clade were evidenced and closely related to sequences from Burkina Faso. The estimated evolutionary rate was 9.29 × 104 . The root of the tree dated back to February 2008 in (95% HPD: 2006-2011). From this ancestor six main statistically supported clusters (pp > 0.80) were identified. The most recent Clade dated back to May 2015. The BSP showed that the effective number of infections softly increased from 2011 to the 2015. Phylogenetic analysis helped in understanding how two on sixteen individuals, have been infected in Italy, and give an important improvement in prevention campaigns and monitoring of the viral infection in migrants. J. Med. Virol. 89:639-646, 2017. © 2016 Wiley Periodicals, Inc.

Hepatitis C virus genotype 3A in a population of injecting drug users in Montenegro: Bayesian and evolutionary analysis.

Few reports are available on HCV molecular epidemiology among IDUs in Eastern Europe, and none in Montenegro. The aim of this study was to investigate the HCV genotype distribution in Montenegro among IDUs and to perform Bayesian and evolutionary analysis of the most prevalent HCV genotype circulating in this population. Sixty-four HCV-positive IDUs in Montenegro were enrolled between 2013 and 2014, and the NS5B gene was sequenced. The Bayesian analysis showed that the most prevalent subtype was HCV-3a. Phylogenetic data showed that HCV-3a reached Montenegro in the late 1990s, causing an epidemic that exponentially grew between the 1995 and 2005. In the dated tree, four different entries, from 1990 (clade D), 1994 (clade A) to 1999 (clade B) and 2001 (clade C), were identified. In the NS5B protein model, the amino acids variations were located mainly in the palm domain, which contains most of the conserved structural elements of the active site. This study provides an analysis of the virus transmission pathway and the evolution of HCV genotype 3a among IDUs in Montenegro. These data could represent the basis for further strategies aimed to improve disease management and surveillance program development in high-risk populations.

Origin and evolution of Nipah virus.

Nipah virus, member of the Paramyxoviridae family, is classified as a Biosafety Level-4 agent and category C priority pathogen. Nipah virus disease is endemic in south Asia and outbreaks have been reported in Malaysia, Singapore, India, and Bangladesh. Bats of the genus Pteropus appear to be the natural reservoir of this virus. The aim of this study was to investigate the genetic diversity of Nipah virus, to estimate the date of origin and the spread of the infection. The mean value of Nipah virus N gene evolutionary rate, was 6.5 × 10(-4) substitution/site/year (95% HPD: 2.3 × 10(-4)-1.18 × 10(-3)). The time-scaled phylogenetic analysis showed that the root of the tree originated in 1947 (95% HPD: 1888-1988) as the virus entered in south eastern Asiatic regions. The segregation of sequences in two main clades (I and II) indicating that Nipah virus had two different introductions: one in 1995 (95% HPD: 1985-2002) which correspond to clade I, and the other in 1985 (95% HPD: 1971-1996) which correspond to clade II. The phylogeographic reconstruction indicated that the epidemic followed two different routes spreading to the other locations. The trade of infected pigs may have played a role in the spread of the virus. Bats of the Pteropus genus, that are able to travel to long distances, may have contributed to the spread of the infection. Negatively selected sites, statistically supported, could reflect the stability of the viral N protein.

Genetic diversity of hepatitis B virus (HBV) in Madagascar.

Hepatitis B virus (HBV) is a DNA virus belonging to Hepadnaviridae family. Chronic infection with HBV is one major risk factor of hepatic disease. In Madagascar, former studies classified the country as part of high endemic area, as HBV prevalence can reach 23% in general population. However, this prevalence differs largely between urban and rural areas and is estimated to be, respectively, 5% and 26%. The aims of the present study were to describe the genetic diversity of HBV strains from different regions of Madagascar, and to describe the viral gene flow throughout the country by using phylogenetic analysis. This is the first large-scale molecular and phylogenetic study analyzing HBV sequences from 28 different Malagasy areas, never sampled in the past. In this study, the most prevalent genotype/sub-genotypes was E. Migration analysis showed a gene flow from zone 3 (rural) to zone 2 (suburban), and a greater gene flow from the middle part of Madagascar to the north than to the south. It is important to study the HBV infections in Madagascar and to monitor the potential spread of this viral strain inside this country. J. Med. Virol. 88:2138-2144, 2016. © 2016 Wiley Periodicals, Inc.

Human papillomavirus detection in paraffin-embedded colorectal cancer tissues.

Human papillomavirus (HPV) has a well-recognized aetiological role in the development of cervical cancer and other anogenital tumours. Recently, an association between colorectal cancer and HPV infection has been suggested, although this is still controversial. This study aimed at detecting and characterizing HPV infection in 57 paired biopsies from colorectal cancers and adjacent intact tissues using a degenerate PCR approach. All amplified fragments were genotyped by means of sequencing. Overall, HPV prevalence was 12.3 %. In particular, 15.8 % of tumour tissues and 8.8 % of non-cancerous tissue samples were HPV DNA-positive. Of these samples, 85.7 % were genotyped successfully, with 41.7 % of sequences identifying four genotypes of the HR (high oncogenic risk) clade Group 1; the remaining 58.3 % of HPV-genotyped specimens had an unclassified ß-HPV. Examining additional cases and analysing whole genomes will help to outline the significance of these findings.

Differential single nucleotide polymorphism-based analysis of an outbreak caused by Salmonella enterica serovar Manhattan reveals epidemiological details missed by standard pulsed-field gel electrophoresis.

We retrospectively analyzed a rare Salmonella enterica serovar Manhattan outbreak that occurred in Italy in 2009 to evaluate the potential of new genomic tools based on differential single nucleotide polymorphism (SNP) analysis in comparison with the gold standard genotyping method, pulsed-field gel electrophoresis. A total of 39 isolates were analyzed from patients (n=15) and food, feed, animal, and environmental sources (n=24), resulting in five different pulsed-field gel electrophoresis (PFGE) profiles. Isolates epidemiologically related to the outbreak clustered within the same pulsotype, SXB_BS.0003, without any further differentiation. Thirty-three isolates were considered for genomic analysis based on different sets of SNPs, core, synonymous, nonsynonymous, as well as SNPs in different codon positions, by Bayesian and maximum likelihood algorithms. Trees generated from core and nonsynonymous SNPs, as well as SNPs at the second and first plus second codon positions detailed four distinct groups of isolates within the outbreak pulsotype, discriminating outbreak-related isolates of human and food origins. Conversely, the trees derived from synonymous and third-codon-position SNPs clustered food and human isolates together, indicating that all outbreak-related isolates constituted a single clone, which was in line with the epidemiological evidence. Further experiments are in place to extend this approach within our regional enteropathogen surveillance system.

Amino acid mutations in Ebola virus glycoprotein of the 2014 epidemic.

Zaire Ebola virus (EBOV) is an enveloped non-segmented negative strand RNA virus of 19 kb in length belonging to the family Filoviridae. The virus was isolated and identified in 1976 during the epidemic of hemorrhagic fever in Zaire. The most recent outbreak of EBOV among humans, was that occurred in the forested areas of south eastern Guinea, that began in February 2014 and is still ongoing. The recent Ebola outbreak, is affecting other countries in West Africa, in addiction to Guinea: Liberia, Nigeria, and Sierra Leone. In this article, a selective pressure analysis and homology modeling based on the G Glycoprotein (GP) sequences retrieved from public databases were used to investigate the genetic diversity and modification of antibody response in the recent outbreak of Ebola Virus. Structural and the evolutionary analysis underline the 2014 epidemic virus being under negative selective pressure does not change with respect to the old epidemic in terms of genome adaptation.

Hepatitis B virus genotype and subgenotype prevalence and distribution in Montenegro.

The Mediterranean area and the Balkans in particular show the highest level of genetic heterogeneity of HBV in Europe. Data about the circulation of HBV genotypes in Montenegro are lacking. It was studied the prevalence and distribution of HBV genot/subgenotypes in a total of 150 HBV infected patients living in Montenegro. Phylogenetic analysis of 136 successfully amplified P sequences showed a high degree of genetic heterogeneity of HBV in Montenegro. Subgenotype D2 (36.8%) and D3 (32.3%) were the most prevalent, followed by genotype A (subgenotype A2 in all of the cases-19.8%). Eight patients were infected with recombinant strains. HBV-D1 which is the most spread HBV subgenotype in the south-eastern Mediterranean countries, seems to be relatively rare in Montenegro, suggesting a penetration of HBV more probably from North-East or West than from Eastern Mediterranean countries. The relatively different prevalence of D3 and A2 among subjects infected through sexual route, seems to confirm the association of these subgenotypes with different route of transmissions (mainly parenteral for D3 and mainly sexual for A2) even in Montenegro. The low prevalence of D2 among children and its absence in perinatal transmission, suggests that this subgenotype circulated prevalently in the past. If this is due to changes in the most prevalent way of transmission and in the recent different contacts of Montenegro with other European countries, it remains to be established by other larger studies.