Relationship between electropherotypes and VP7/VP4 genotypes of group A rotaviruses detected between 2000 and 2007 in Tunisian children.

BACKGROUND: Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to detect a relationship between electropherotype pattern and molecular characteristics of the rotavirus strains. MATERIAL AND METHODS: Were analyzed 278 rotavirus-positive specimens by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR. Pearson's correlation tests were used for statistical analysis. RESULTS: Twelve different electropherotypes were visualized, eight with a long profile (186 cases) and four with a short one (87 cases). Concerning VP7 types, G2 viral strains were found to be predominant and were detected in 91 specimens (32.7%). Strains with G1, G3, G4, G8 and G9 specificities were detected in 62 (22.3%), 82 (29.5%), 13 (4.7%), two (0.7%) and seven cases (2.5%), respectively. The results of VP4 genotyping showed a predominance of P[8] genotype which comprised half of the strains identified (139 cases, 50%). VP4 P[4], P[6] and P[11] were found in 83 (29.9%), 31 (11.1%) and 11 (4.0%) specimens, respectively. A high rate of mixed strains was also found (1.8% mixed electropherotypes, 7.6% G-mixed and 5% P-mixed strains). Electropherotype pattern of rotavirus strains was significantly correlated with VP7 genotype (p=0.018) and with VP4 genotype specificities (p<0.001).

[Evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007)]. / Évolution des souches de Rotavirus du groupe A en circulation en Tunisie sur une période de trois ans (2005-2007).

BACKGROUND: Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to determine the evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007). MATERIAL AND METHODS: A total of 1503 stool samples collected from children less than five years old, consulting or hospitalised in Tunisia for diarrhoea between 2005 and 2007, were screened for the presence of group A Rotaviruses. Rotavirus-positive specimens were further analyzed by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR. RESULTS: Rotaviruses were detected in 323 stool samples over 1503 (21 %). Long electropherotypes predominated in Tunisia during the whole period of study (N=158 vs N=82 short electropherotypes). VP7 genotyping showed the cocirculation of five different genotypes: G1, G2, G3, G4 and G9. VP4 typing detected four different P-genotypes: P[8], P[4], P[6] and P[11]. Rotavirus strains with G3P[8] specificity were predominating in Tunisia in 2005 and 2006, replaced by G2P[4] strains in 2007.

Clinical Features of Rotavirus Infections : Influence of Child Age on Clinical Manifestations

Objectifs : Decrire les caracteristiques cliniques des infections a Rotavirus et comparer les symptomes observes en fonction de l'age des enfants. Malades et methodes : Les dossiers cliniques de 278 enfants de moins de 5 ans infectes par le Rotavirus ont ete consultes retrospectivement. La presence d'antigenes de Rotavirus du groupe A dans les selles a ete detectee par la technique immunoenzymatique. Une correlation statistique entre les signes cliniques et l'age des enfants a ete recherchee au moyen des tests de correlation de Pearson. Resultats : Parmi les 278 enfants positifs a Rotavirus; 93;9ont presente une diarrhee; 79;1des vomissements; 71;6de la fievre; 37;4des signes respiratoires et 33;1des troubles neurologiques. Une rehydratation intraveineuse requise pour 59;7des enfants. D'une facon generale; la diarrhee (p = 0;001); les vomissements (p = 0;007); la fievre (p=0;045); les troubles respiratoires (p = 0;01) et la deshydratation (p 0;001) etaient significativement plus frequents chez les nourrissons de 1-24 mois par rapport aux autres enfants infectes. Conclusion : La severite du syndrome clinique induit par les infections a Rotavirus semble etre directement influencee par l'age de l'enfant. Il etait interessant de noter que les nourrissons de 1 a 5 mois ont presente des formes cliniques souvent aussi severes que ceux de 6 a 24 mois