Phylogenetic Analysis of Echovirus 11 in the 3′ End of the VP1

International audienceObjective: Echovirus 11 is one of the most frequently isolated enterovirus serotypes, causing a wide range of clinical diseases. We studied the genetic diversity in the 3' end of the VP1 gene of strains from different geographical origin in the world. Methods: The sequences in the 3' end of the VP1 of 11 Tunisian isolates were determined and aligned with the published sequences to establish a phylogenetic profile. Results: The grouping of the sequences was similar to what was previously reported by analyzing the whole VP1 gene with 4 genogroups, designated A-D, and 5 lineages in genogroup D. All Tunisian strains belonged to genogroup D, together with other sequences mainly from the USA and Europe. Contrary to the sequences from the USA isolated during the last 3 decades, which mostly belonged to the D4 lineage, those from Tunisia belonged to different lineages within genogroup D according to their isolation date: isolates from the early 1990s belonged to D3, those of the mid 1990s to D4 and the most recent ones to D5. Conclusion: Our findings further widen the interest of partial sequencing in the VP1 to study the molecular epidemiology of echovirus 11 and indicate that the genetic evolution of circulating strains may differ from one country to another according to the region's epidemiological specificities. Copyright (c) 2007 S. Karger AG, Basel

Molecular epidemiology of coxsackievirus type B1

International audienceCoxsackievirus type B1 (CVB1) has emerged globally as the predominant enterovirus serotype and is associated with epidemics of meningitis and chronic diseases. In this report, the phylogeny of CVB1 was studied based on the VP1 sequences of 11 North African isolates and 81 published sequences. All CVB1 isolates segregated into four distinct genogroups and 10 genotypes. Most of the identified genotypes of circulating CVB1 strains appear to have a strict geographical specificity. The North African strains were of a single genotype and probably evolved distinctly. Using a relaxed molecular clock model and three different population models (constant population, exponential growth and Bayesian skyline demographic models) in coalescent analysis using the BEAST program, the substitution rate in CVB1 varied between 6.95 x 10(-3) and 7.37 x 10(-3) substitutions/site/year in the VP1 region. This study permits better identification of circulating CVB1, which has become one of the most predominant enterovirus serotypes in humans

Identification of measles virus genotypes from recent outbreaks in countries from the Eastern Mediterranean Region

International audienceBackground: Molecular characterization of measles viruses (MV) helps to identify transmission pathways of the virus and to document persistence or interruption of endemic virus circulation. In the Eastern Mediterranean Region, measles genotypes from only few countries have been documented.Objectives: This study reports the genetic characteristics of virus strains from recent measles outbreaks in Tunisia, Libya, Syria and Iran in 2002–2003.Study design: Virus sequences in the nucleoprotein gene were obtained by PCR amplification of virus isolates or serum samples. The sequences were compared to the reference ones for genotype identification and to other published sequences within the same genotype.Results and conclusions: The Tunisian and Libyan epidemic strains belonged to genotype B3, they were closely related to each other and to isolates from Western Africa. The Syrian and Iranian viruses belonged to genotype D4, and differed from each other and from the other published sequences within this genotype. Our results provide valuable baseline and new tools for improved virological measles surveillance in the future, at country, regional and global levels

Circulation and Molecular Epidemiology of Enteroviruses in Paralyzed, Immunodeficient and Healthy Individuals in Tunisia, a Country with a Polio-Free Status for Decades

This report is an overview of enterovirus (EV) detection in Tunisian polio-suspected paralytic cases (acute flaccid paralysis (AFP) cases), healthy contacts and patients with primary immunodeficiencies (PID) during an 11-year period. A total of 2735 clinical samples were analyzed for EV isolation and type identification, according to the recommended protocols of the World Health Organization. Three poliovirus (PV) serotypes and 28 different nonpolio enteroviruses (NPEVs) were detected. The NPEV detection rate was 4.3%, 2.8% and 12.4% in AFP cases, healthy contacts and PID patients, respectively. The predominant species was EV-B, and the circulation of viruses from species EV-A was noted since 2011. All PVs detected were of Sabin origin. The PV detection rate was higher in PID patients compared to AFP cases and contacts (6.8%, 1.5% and 1.3% respectively). PV2 was not detected since 2015. Using nucleotide sequencing of the entire VP1 region, 61 strains were characterized as Sabin-like. Among them, six strains of types 1 and 3 PV were identified as pre-vaccine-derived polioviruses (VDPVs). Five type 2 PV, four strains belonging to type 1 PV and two strains belonging to type 3 PV, were classified as iVDPVs. The data presented provide a comprehensive picture of EVs circulating in Tunisia over an 11-year period, reveal changes in their epidemiology as compared to previous studies and highlight the need to set up a warning system to avoid unnoticed PVs

Circulation and Molecular Epidemiology of Enteroviruses in Paralyzed, Immunodeficient and Healthy Individuals in Tunisia, a Country with a Polio-Free Status for Decades

This report is an overview of enterovirus (EV) detection in Tunisian polio-suspected paralytic cases (acute flaccid paralysis (AFP) cases), healthy contacts and patients with primary immunodeficiencies (PID) during an 11-year period. A total of 2735 clinical samples were analyzed for EV isolation and type identification, according to the recommended protocols of the World Health Organization. Three poliovirus (PV) serotypes and 28 different nonpolio enteroviruses (NPEVs) were detected. The NPEV detection rate was 4.3%, 2.8% and 12.4% in AFP cases, healthy contacts and PID patients, respectively. The predominant species was EV-B, and the circulation of viruses from species EV-A was noted since 2011. All PVs detected were of Sabin origin. The PV detection rate was higher in PID patients compared to AFP cases and contacts (6.8%, 1.5% and 1.3% respectively). PV2 was not detected since 2015. Using nucleotide sequencing of the entire VP1 region, 61 strains were characterized as Sabin-like. Among them, six strains of types 1 and 3 PV were identified as pre-vaccine-derived polioviruses (VDPVs). Five type 2 PV, four strains belonging to type 1 PV and two strains belonging to type 3 PV, were classified as iVDPVs. The data presented provide a comprehensive picture of EVs circulating in Tunisia over an 11-year period, reveal changes in their epidemiology as compared to previous studies and highlight the need to set up a warning system to avoid unnoticed PVs

Development of a New Internally Controlled One-Step Real-Time RT-PCR for the Molecular Detection of Enterovirus A71 in Africa and Madagascar

International audienceEnterovirus A71 (EV-A71) is a leading cause of hand-foot-and-mouth disease (HFMD) and can be associated with severe neurological complications. EV-A71 strains can be classified into seven genogroups, A-H, on the basis of the VP1 capsid protein gene sequence. Genogroup A includes the prototype strain; genogroups B and C are responsible of major outbreaks worldwide, but little is known about the others, particularly genogroups E and F, which have been recently identified in Africa and Madagascar, respectively. The circulation of EV-A71 in the African region is poorly known and probably underestimated. A rapid and specific assay for detecting all genogroups of EV-A71 is required. In this study, we developed a real-time RT-PCR assay with a competitive internal control (IC). The primers and TaqMan probe specifically target the genomic region encoding the VP1 capsid protein. Diverse EV-A71 RNAs were successfully amplified from the genogroups A, B, C, D, E, and F, with similar sensitivity and robust reproducibility. Neither cross reaction with other EVs nor major interference with the competitive IC was detected. Experimentally spiked stool and plasma specimens provided consistent and reproducible results, and validated the usefulness of the IC for demonstrating the presence of PCR inhibitors in samples. The analysis in an African laboratories network of 1889 untyped enterovirus isolates detected 15 EV-A71 of different genogroups. This specific real-time RT-PCR assay provides a robust and sensitive method for the detection of EV-A71 in biological specimens and for the epidemiological monitoring of EV-A71 including its recently discovered genogroups

First whole genome sequences and phylogenetic analysis of SARS-CoV-2 virus isolates during COVID-19 outbreak in Tunisia, North Africa.

International audienceFull genomes sequences of six Tunisian SARS-CoV-2 strains were obtained from imported and locally transmission cases during the COVID-19 outbreak. Reported sequences were non-identical with 0.1% nucleotide divergence rate and clustered into 6 different clades with worldwide sequences. SNPs results favor the distribution of the reported Tunisian sequences into 3 major genotypes. These results indicate multiple introductions of the virus in Tunisia and add new genomic data on SARS-CoV-2 at the international level

Whole genome sequencing and phylogenetic analysis of six SARS-CoV-2 strains isolated during COVID-19 pandemic in Tunisia, North Africa

International audienceBackground: In Tunisia a first SARS-CoV-2 confirmed case was reported in March 03, 2020. Since then, an increase of cases number was observed from either imported or local cases. The aim of this preliminary study was to better understand the molecular epidemiology and genetic variability of SARS-CoV-2 viruses circulating in Tunisia and worldwide. Methods: Whole genome sequencing was performed using NGS approach on six SARS. CoV-2 highly positive samples detected during the early phase of the outbreak. Results: Full genomes sequences of six Tunisian SARS-CoV-2 strains were obtained from imported and locally transmission cases during the COVID-19 outbreak. Reported sequences were non-identical with 0.1% nucleotide divergence rate and clustered into 6 different clades with worldwide sequences. SNPs results favor the distribution of the reported Tunisian sequences into 3 major genotypes. These SNP mutations are critical for diagnosis and vaccine development. Conclusions: These results indicate multiple introductions of the virus in Tunisia and add new genomic data on SARS-CoV-2 at the international level