Henda Touzi

High Susceptibility for Enterovirus Infection and Virus Excretion Features in Tunisian Patients with Primary Immunodeficiencies

ABSTRACT To estimate the susceptibility to enterovirus infection and the frequency of long-term poliovirus excreters in Tunisian patients with primary immunodeficiencies (PIDs), enteroviruses were assessed in stool specimens of 82 patients with humoral, combined, and other PIDs. Isolated viruses were typed and intratyped by standard molecular techniques, and the whole VP1 region of poliovirus isolates was sequenced. Polioviruses were detected in 6 patients; all isolates were vaccine related. Five patients rapidly stopped excretion; one excreted a poliovirus type 1 isolate for several months, and the isolate accumulated up to 14 mutations in the VP1 region. Nonpolio enteroviruses were identified in 6 patients; 4 of them kept excreting the same strain for more than 6 months. The rate of enterovirus infection was 13.4% of the PID patients and 20.7% of those with an IgG defect; it greatly exceeded the rates generally found in Tunisian supposed-immunocompetent individuals (4.1% during the study period; P = 0.001 and P < 0.0001, respectively). Interestingly, patients with combined immunodeficiencies were at a higher risk for enterovirus infection than those with an exclusively B cell defect. A major histocompatibility complex (MHC) class II antigen expression defect was found in 54% of enterovirus-positive patients and in the unique long-term poliovirus excreter. The study results also suggest that substitutive immunoglobulin therapy may help clearance of a poliovirus infection and that most PID patients have the ability to stop poliovirus excretion within a limited period. However, the high susceptibility of these patients to enterovirus infection reinforces the need for enhanced surveillance of these patients until the use of oral poliovirus vaccine (OPV) is stopped.

Phylogenetic analysis of complete VP1 sequences of echoviruses 11 and 6: high genetic diversity and circulation of genotypes with a wide geographical and temporal range

Echovirus 6 (E6) and echovirus 11 (E11) are common causes of meningitis and other human diseases; they are among the most frequently isolated enteroviruses worldwide. In the present work we have studied genetic variability over the entire VP1 gene of selected isolates representing a wide geographical and temporal range. Fifty new sequences from North Africa were included, together with previously published sequences from different countries. The sequence diversity between strains of the same type was high: 22 and 30 % for E6 and E11, respectively. Phylogenetic analysis revealed five genogroups within each type, the genetic diversity within a genogroup generally being <20 %. Some genogroups were further subdivided into genotypes, most containing isolates that had circulated over a wide geographical (several countries from different continents) and temporal (up to two decades) range. Several genotypes were also shown to co-circulate in a region during the same period of time. These features differ from other enteroviruses that divide into temporal or geographical clusters. This study reports new sequences from North Africa, updates the molecular epidemiology of E6 and E11, and proposes a new genogroup in each type.

[Retrospective study of viral causes of central nervous system infections in Tunisia (2003-2009)].

OBJECTIVES To determine the role of enteroviruses, Herpesviridae, West Nile virus and Sandfly Toscana virus in central nervous system (CNS) infections in Tunisia. METHODOLOGY 847 cerebrospinal fluid (CSF) samples, 427 serum samples and 23 stool samples were collected from 1071 patients hospitalized for CNS viral infections from January 2003 through December 2009. All CSF samples were first tested by PCR to detect enteroviruses and Herpesviridae. In specific epidemic contexts in patients negative for these viruses, arbovirus infection was tested by ELISA. RESULTS Virological testing was positive in 17.5% of cases. West Nile virus and enteroviruses accounted for 58% of them, enteroviruses 23.5%, Herpesviridae 8.5%, and Toscana virus 10%. West Nile virus infection was observed only in 2003, during an outbreak in coastal regions. Toscana virus circulated regularly throughout the study period. Enteroviruses were responsible for grouped cases of aseptic meningitis in both 2003 and 2005. Arboviruses and enteroviruses were detected mainly in summer and autumn. Herpesviridae were associated with sporadic cases of meningoencephalitis. CONCLUSION This report on viral causes of CNS infections in Tunisia shows that West Nile virus and enteroviruses appear to circulate mainly during epidemics, while the circulation of Toscana virus seems continuous. Negative virus findings may be due, at least in part, to late sampling, inappropriate sample collection and transportation to the virology lab, or failure to test for the right virus. It is essential to promote collaboration between clinicians and biologists to maximize the likelihood of diagnosis.

Sequential Asymptomatic Enterovirus Infections in a Patient with Major Histocompatibility Complex Class II Primary Immunodeficiency

ABSTRACT Patients with primary immunodeficiencies are usually susceptible to enterovirus infections and have higher risks to develop severe clinical forms. We report a unique description of a boy with major histocompatibility complex class II (MHC-II) deficiency infected by 9 different enterovirus serotypes during a 2-year period, with very mild clinical symptoms, probably due to the immunoglobulin therapy he was receiving.

Cytopathic effect of Human cosavirus (HCoSV) on primary cell cultures of human embryonic lung MRC5

Human cosaviruses (HCoSVs) are newly discovered viruses in Picornaviridae family. Until now, most published studies reported HCoSV detection using molecular techniques and genetic characterization of the virus. Nevertheless, no laboratory has yet reported the replication of these viruses in cultured cell lines. In the present work, the propagation of HCoSV strains isolated from human fecal specimens in MRC5 cell line and their induced cytopathic effects (CPE) was studied. The first sign of virus growth was observed 24-48h after inoculation. The cells rounded up and clumped together rapidly; empty areas became visible and, on the third day of CPE, a remarkable decrease in live cells was observed. This represents the first report on in vitro model of HCoSV replication which opens up opportunities for future investigations of these new viruses.

Evaluation of PCR-RFLP in the Pre-S Region as Molecular Method for Hepatitis B Virus Genotyping

Background Hepatitis B virus (HBV) infection is a public health problem in developing countries. HBV genotypes play major role in the evolution of infection since they were involved in different clinical presentations and response to treatment. Objectives This study was conducted to evaluate the efficiency of restriction fragment length polymorphism (RFLP) analysis for HBV genotyping. Patients and Methods We investigated 98 samples collected from patients chronically infected with HBV. HBV genotypes were determined by analysis of patterns obtained after amplification in Pre-S region and digestion of the amplicon by two endonucleases AvaII and DpnII. Obtained results were confirmed by partial sequencing in the same region. Results Two different HBV genotypes were detected in this study, Genotype D (in 95. 9%) and Genotype A (in 4.1%). Seventy-four samples (75.5%) were successfully genotyped with RFLP analysis and all classified as genotype D. The remaining 24 samples (24.5%) which were un-genotyped by RFLP analysis, were classified by partial sequencing of the pre-S region as HBV genotype D (20 samples, 20.4%) and genotype A (4 samples, 4.1%). Atypical profiles were significantly associated with advanced liver disease (P = 0.001) as well as older age (P < 0.05). Conclusions Several previous studies used PCR-RFLP to genotype HBV; however, we showed the high risk to obtain atypical profiles, especially in advanced stages of chronic infection, with as results difficulties to genotype the virus. These profiles resulted from the accumulation of mutations during natural course of infection resulting in a modification in restriction sites for enzymes. So, we recommended completing the investigation by partial sequencing to confirm obtained results.

Genetic variability of human adenovirus type 8 causing epidemic and sporadic cases of keratoconjunctivitis

Human adenovirus type 8 (HAdV-8) is a main aetiological agent of keratoconjunctivitis. It has been reported from both epidemic and sporadic cases. The aim of our study was to investigate the genetic characteristics and chronological pattern of HAdV-8 strains that have been circulating in Tunisia over a 14-year period. Fourteen HAdV-8 isolates from a keratoconjunctivitis outbreak that occurred in 2000 and from sporadic cases between 2001 and 2013 were studied. Nucleotide sequences from the hexon, fiber and penton base genes were determined, including hypervariable regions of the hexon (loops 1 and 2), the fiber (knob) and the penton base (HVR 1 and RGD loops). The sequences were compared to each other and to those of HAdV-8 strains. The Tunisian sequences were unique when compared to the previously published sequences. Also, despite a relatively low degree of genetic variation in the three genomic regions, phylogenetic analysis and alignment of amino acid sequences showed that the sequence from the year 2000 and two other sequences from the year 2013 were similar to each other and differed from the isolates that circulated in the intervening year by two main amino acid changes in the loop 1 hexon gene and the knob-fiber gene. Our results confirm the genetic variability of HAdV-8 and document the chronological changes of circulating genetic variants.

Variabilité génétique des échovirus de type 3

Ce travail a pour but d’etudier la variabilite genetique et antigenique dans la region VP1 des echovirus de type 3 (E-3), serotype d’enterovirus incrimine dans des cas de meningites, d’atteintes neuromusculaires et de diabete de type 1 chez l’homme. Quarante-six sequences VP1 de souches E-3, dont 9 isolees chez des enfants tunisiens ont ete incluses. Analyses phylogenetiques et taux de divergence nucleotidique ont ete etudies sur la totalite de la VP1 et sur une portion de 290 nucleotides dans la partie 5’ de la VP1. Les sequences en acides amines ont ete deduites a la recherche de determinants antigeniques specifiques de genotypes. Les sequences E-3 se sont reparties en deux genogroupes, I et II ; la variabilite genetique globale au sein du serotype atteint 29,1 %. Le genogroupe I comporte des sequences assez heterogenes, certaines se regroupent en un genotype avec au plus 15,1 % de divergence. Les sequences du genogroupe II ont un maximum de divergence de 13,8 % et correspondraient a un seul genotype. Les deux genogroupes co-circulent et ont une distribution temporospatiale a large etendue. Des substitutions d’acides amines, pouvant etre specifiques de genogroupe, de genotype ou de variants particuliers, ont ete relevees. Ce travail est une premiere tentative de classification des E-3 en genogroupes et genotypes et rapporte de nouvelles sequences d’origine nord-africaine. Il contribue a une meilleure connaissance de l’epidemiologie moleculaire des enterovirus en general et des E-3 en particulier, serotype jusque-la tres peu etudie dans la litterature.