Etude des gastro-entérites virales pédiatriques en Tunisie (suivi épidémiologique et clinique et caractérisation moléculaire des virus entériques isolés des milieux cliniques et environnementaux entre 2003 et 2007)

Les gastro-entérites aiguës virales constituent un problème de santé publique mondial avec une morbidité et une mortalité importantes chez le jeune enfant, surtout dans les pays en voie de développement. Cette étude constitue la première investigation virologique, épidémiologique et clinique des cinq principaux virus responsables de gastro-entérites en Tunisie. Nos résultats montrent que les rotavirus du groupe A et les norovirus étaient les plus fréquemment détectés dans respectivement 213 (27%) et 128 (16,2%) cas. Les rotavirus du groupe A, les norovirus et les virus Aichi étaient significativement plus fréquents chez les enfants hospitalisés que chez les externes. Chez les enfants hospitalisés, contrairement à d autres études, aucune différence significative de la fréquence et de la sévérité de la diarrhée entre les rotavirus et les norovirus n a été détectée. Le typage moléculaire a montré que les souches prédominantes dans les selles diarrhéiques étaient le rotavirus A de type G3P[8] et le norovirus de type GII.4, variant Hunter. Une donnée intéressante est que ce variant a été retrouvé chez les enfants tunisiens dès janvier 2003, alors qu il n a été détecté pour la première fois qu en février 2004, en Europe. Dans les prélèvements d eaux usées, les rotavirus ont été détectés dans 80 (32 %) prélèvements, les norovirus dans 11 (4,4 %), les virus Aichi dans 15 (6 %) et les adénovirus 40/41 dans 1 (0,4 %) seul prélèvement. Une corrélation entre les souches détectées dans les eaux usées et les coquillages et celles retrouvées dans les selles des patients a été démontrée. Ceci suggère qu il existe une relation entre la contamination hydrique et les diarrhées infantiles.Viral acute gastroenteritis is a worldwide problem of public health with an important morbidity and mortality in young children, especially in developing countries. This study constitutes the first viral, epidemiological and clinical investigation of the five main viruses responsible for gastroenteritis in Tunisia. Our results show that Group A rotaviruses and noroviruses were the most frequently detected with 213 (27%) and 128 (16.2%) cases, respectively. Group A rotaviruses, noroviruses and Aichi viruses were significantly more frequent in hospitalized children than in outpatients. In hospitalized children, contrary to other studies, no significant difference was observed between rotavirus and norovirus infections with regard to the incidence and the clinical severity of the disease. The molecular typing showed the predominant strains as rotavirus type G3P[8] and norovirus genotype GGII.4, variant Hunter. One interesting finding is that this variant was detected in Tunisian children as soon as January 2003, whereas it was described for the first time in Europe in February 2004. In the sewage samples, rotaviruses were detected in 80 (32%) cases, noroviruses in 11 (4.4%) cases, Aichi viruses in 15 (6%) cases and adenoviruses type 40/41 in 1 (0.4%) sample. A correlation between the strains detected in the sewage and the shellfish and the strains detected in the human stools has been shown. This suggests the existence of a relation between water contamination and pediatric diarrheas. This study provide very interesting data that permit a better understanding of the molecular and clinical epidemiology of enteric viruses in Tunisia and in Africa for which data are very rare.DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF

New Parvovirus in Child with Unexplained Diarrhea, Tunisia

A divergent parvovirus genome was the only eukaryotic viral sequence detected in feces of a Tunisian child with unexplained diarrhea. Tusavirus 1 shared 44% and 39% identity with the nonstructural protein 1 and viral protein 1, respectively, of the closest genome, Kilham rat parvovirus, indicating presence of a new human viral species in the Protoparvovirus genus

Physical-chemical characterization of Tunisian clays for the synthesis of geopolymers materials

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Molecular Epidemiology of Norovirus Gastroenteritis Investigated Using Samples Collected from Children in Tunisia during a Four-Year Period: Detection of the Norovirus Variant GGII.4 Hunter as Early as January 2003 ▿

Human noroviruses (NoVs) cause epidemic and endemic acute gastroenteritis in children and adults. To study the prevalence and genetic diversity of NoV in children in Tunisia, a total of 788 fecal samples were collected during a 4-year period in the region of Monastir, from children 12 years of age or younger, hospitalized or presenting in dispensaries with symptoms of acute gastroenteritis. NoV was detected by reverse transcription-PCR and confirmed by sequence analysis. This is the first report that describes the molecular epidemiology of NoV in Tunisian children: NoVs were characterized as the causative agent in 128 (16.2%) of the samples. Fourteen samples contained a mixture of two NoVs, and 33 samples were coinfected with additional enteric viruses. Eight distinct NoV genotypes were detected (GGI.2, GGI.4, GGII.1, GGII.4, GGII.8, GGII.14, GGIIb/GGII.2, and GGIIb/GGII.3). GGII.4 was the most prevalent genotype, accounting for 83 (64.8%) cases. Interestingly the GGII.4 variant Hunter, described as spreading all over the world in 2004, was found in Tunisia as early as January 2003. The delay of 1 year between the isolation in Tunisia and the worldwide emergence is somewhat surprising, considering the importance of the contacts between North Africa and Europe particularly. Nevertheless, this illustrates the idea that sporadic gastroenteritis cases may be a reservoir for emerging epidemic NoV strains

Detection and Genomic Characterization of Aichi Viruses in Stool Samples from Children in Monastir, Tunisia▿

Aichi virus has been associated with acute gastroenteritis in adults and children. Stool samples were collected from 788 Tunisian children suffering from diarrhea. Aichi virus was found in 4.1% of the cases. The high proportion of monoinfections and the high frequency of hospitalizations support the role of Aichi virus in pediatric gastroenteritis

Molecular epidemiology of human astrovirus and adenovirus serotypes 40/41 strains related to acute diarrhea in Tunisian children.

International audienceHuman 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

Acute infantile gastroenteritis associated with human enteric viruses in Tunisia.

International audienceThis prospective study, conducted from January 2003 to June 2005, 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 (1.0%). 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

Rotavirus P[8] Infections in Persons with Secretor and Nonsecretor Phenotypes, Tunisia

To determine whether rotavirus infections are linked to secretor status, we studied samples from children in Tunisia with gastroenteritis. We phenotyped saliva for human blood group antigens and tested feces for rotavirus. Rotavirus was detected in 32/114 patients. Secretor genotyping showed that P[8] rotavirus infected secretors and nonsecretors, and infection correlated with presence of Lewis antigen