Mohamed Sdiri - Academia.edu (original) (raw)

Papers by Mohamed Sdiri

Journal of Medical Virology, 2009

Human astrovirus (AstV) and adenovirus types 40 and 41 (AdV 40/41) are responsible for epidemic a... more Human astrovirus (AstV) and adenovirus types 40 and 41 (AdV 40/41) are responsible for epidemic and endemic acute gastroenteritis in children and adults. The present study was designed to evaluate the prevalence and genetic diversity of enteric viruses in children in Tunisia. A total of 788 fecal samples were collected during a 4-year period in the region of Monastir, from children under 12 years old, hospitalized or presenting in dispensaries with symptoms of acute gastroenteritis. AstV and AdV40/41 were detected by immunoenzymatic methods and confirmed by PCR/RT-PCR and sequence analysis. Phylogenetic analyses were performed for nucleotide homology with reference strains. AstV and AdV40/41 were characterized as a causative agent in 28 (3.6%) and 18 (2.3%) of the fecal samples, respectively. Phylogenetic analysis showed that the AstVs belonged to the serotypes 3 (n = 4; 14.3%) and 1 (n = 24; 85.7%), and the enteric AdVs to the serotypes 40 (n = 1; 5.6%) and 41 (n = 17; 94.4%). This is the first report that describes the molecular epidemiology of AstV and AdV40/41 in Tunisian children. Their respective detection rate was very low, far below that of rotavirus and norovirus. The genetic diversity among these two viruses is relatively limited and varies depending on the area. J. Med. Virol. 81:1895–1902, 2009. © 2009 Wiley-Liss, Inc.

Role of the Tunisian service firms internationalization in promoting innovation

Résumé L'innovation dans les services est un sujet d'importance majeur. Mais, la plupar... more Résumé L'innovation dans les services est un sujet d'importance majeur. Mais, la plupart des travaux se concentrent essentiellement sur l'analyse des ressources internes de l'entreprise et leurs effets sur l'innovation. Cette analyse est certes importante, mais rares ...

Innovation decision of Tunisian service firms: an empirical analysis

Innovation is widely recognised as a key driver of economic growth and competitiveness. But, some... more Innovation is widely recognised as a key driver of economic growth and competitiveness. But, some works focus especially on analyzing the determinants and the effects of innovation while distinguishing between its various types (product innovation, process innovation, ...

Innovation and outsourcing of services: a firm-level analysis

Explaining the decisions to innovate: the case of Tunisian service firms

Résumé Il est largement connu que l'innovation est un véritable moteur de la croissance et d... more Résumé Il est largement connu que l'innovation est un véritable moteur de la croissance et de la compétitivité. Mais, la plupart des travaux se focalisent essentiellement sur l'analyse des déterminants et des effets de l'innovation tout en distinguant entre ses différents types ...

Journal of Applied Microbiology, 2010

Aims: A prospective study was performed to characterize the main human enteric viruses able to p... more Aims: A prospective study was performed to characterize the main human enteric viruses able to persist in sewage samples and in shellfish tissues, and to establish the correlation between environmental strains and viral infantile diarrhoea observed in the same area during the same period.Methods and Results: A total of 250 sewage (raw and treated) and 60 shellfish samples were collected between January 2003 and April 2007 in Monastir region, Tunisia. Group A rotavirus (RVA) was detected in 80 (32%) sewage samples, norovirus (NoV) in 11 (4·4%) and enteric adenovirus (AdV) in 1 (0·4%). Among 60 shellfish samples collected near sewage effluents, one was contaminated by NoV (1·6%).Conclusion: Our data represent the first documentation in Tunisia, combining gastroenteritis viruses circulating in the environment and in clinical isolates. We observed a correlation between environmental strains and those found in children suffering from gastroenteritis during the same period study. This suggests the existence of a relationship between water contamination and paediatric diarrhoea.Significance and Impact of the Study: Our results address the potential health risks associated with transmission of human enteric viruses through water-related environmental routes. The research findings will aid in elucidating the molecular epidemiology and circulation of enteric viruses in Tunisia and in Africa, where data are rare.

Clinical and Vaccine Immunology, 2010

Aichi virus has been described as a novel causative agent of gastroenteritis in humans. In this s... more Aichi virus has been described as a novel causative agent of gastroenteritis in humans. In this study, we report the seroprevalence distribution of Aichi virus in Tunisia. A panel of 1,000 sera was screened by applying an enzyme-linked immunosorbent assay for immunoglobulin G specific for Aichi virus. A considerable prevalence (92%) of antibody to Aichi virus was found across all age groups. The specific anti-Aichi virus antibodies increased with age, from a high rate (68.8%) in children under 10 years old to about 100% in persons more than 60 years old. We found a statistically significant increase in levels of antibody to Aichi virus according to the age of patients. Immunoglobulin M antibodies were detected among five children. A high frequency of Aichi virus monoinfections in hospitalized children with severe gastroenteritis was previously observed in Tunisia.

Virus Genes, 2011

This study investigated the prevalence of sapovirus infections in children with acute gastroenter... more This study investigated the prevalence of sapovirus infections in children with acute gastroenteritis in Monastir region, Tunisia, from January 2003 to April 2007. Sapovirus was characterized by sequence and phylogenetic analyses of the partial polymerase gene. From 788 fecal specimens tested, 6 (0.8%) were positive for sapovirus, of these, 4 (66.7%) were monoinfections. All sapovirus positive samples were detected in outpatient, contrary to norovirus which was significantly more frequent in hospitalized children than in outpatients (14.5 vs. 9.5%, P = 0.03). The mean age of children with sapovirus infections was 11 ± 5.56 months (range 6–19 months). Sapovirus isolates were detected in March and between September and December 2003. Fever, vomiting, abdominal pain, and dehydration were not observed in patients with sapovirus infections. Analysis of nucleotide and amino acid sequences revealed that all 6 Tunisian sapovirus strains clustered in the GGI/1 genotype and strains were identical in the region sequenced, sharing 90.2% nucleotide identity with the reference strain Sapporo/82/JP (U65427). This represents the first finding of sapovirus infections in North Africa and especially in Tunisia. The data indicate that, contrary to norovirus which can cause severe diarrhea and is an important etiologic agent in hospitalized cases, sapovirus causes mild gastroenteritis in Tunisian children.

Journal of Clinical Microbiology, 2008

investigated the incidence and the clinical role of various enteric viruses responsible for infan... more investigated the incidence and the clinical role of various enteric viruses responsible for infantile gastroenteritis in 632 Tunisian children presenting in dispensaries (380 children) or hospitalized (252 children) for acute diarrhea. At least one enteric virus was found in each of 276 samples (43.7%). A single pathogen was observed in 234 samples, and mixed infections were found in 42 samples. In terms of frequency, rotavirus and norovirus were detected in 22.5 and 17.4% of the samples, respectively, followed by astrovirus (4.1%), Aichi virus (3.5%), adenovirus types 40 and 41 (2.7%), and sapovirus (1. . The seasonal distribution of viral gastroenteritis showed a winter peak but also an unusual peak from May to September. The severity of the diarrhea was evaluated for hospitalized infants. No significant differences were observed between rotavirus and norovirus infections with regard to the incidence and the clinical severity of the disease, especially in dehydration.