Rotavirus Rearranged Genomic RNA Segments Are Preferentially Packaged into Viruses Despite Not Conferring Selective Growth Advantage to Viruses

The rotavirus (RV) genome consists of 11 double-stranded RNA segments. Sometimes, partial sequence duplication of an RNA segment leads to a rearranged RNA segment. To specify the impact of rearrangement, the replication efficiencies of human RV with rearranged segments 7, 11 or both were compared to these of the homologous human wild-type RV (wt-RV) and of the bovine wt-RV strain RF. As judged by viral growth curves, rotaviruses with a rearranged genome (r-RV) had no selective growth advantage over the homologous wt-RV. In contrast, r-RV were selected over wt-RV during competitive experiments (i.e mixed infections between r-RV and wt-RV followed by serial passages in cell culture). Moreover, when competitive experiments were performed between a human r-RV and the bovine wt-RV strain RF, which had a clear growth advantage, rearranged segments 7, 11 or both always segregated in viral progenies even when performing mixed infections at an MOI ratio of 1 r-RV to 100 wt-RV. Lastly, bovine reassortant viruses that had inherited a rearranged segment 7 from human r-RV were generated. Although substitution of wt by rearranged segment 7 did not result in any growth advantage, the rearranged segment was selected in the viral progenies resulting from mixed infections by bovine reassortant r-RV and wt-RV, even for an MOI ratio of 1 r-RV to 107 wt-RV. Lack of selective growth advantage of r-RV over wt-RV in cell culture suggests a mechanism of preferential packaging of the rearranged segments over their standard counterparts in the viral progeny

Epidemiological study of infantile rotavirus diarrhoea in Tananarive (Madagascar).

International audienceAn epidemiological study of rotavirus infections was conducted in Tananrive, Madagascar, from November 1988 to October 1990. Rotavirus antigen was detected by ELISA in faecal specimens of 183 of 1,659 children with acute diarrhoea (11%) and in 11 of 631 specimens from children without diarrhoea (1.7%). Rotaviral diarrhoeas were most frequently found in infants aged 6 to 18 months and occurred throughout the year with a definite peak during the first winter months. Analysis of the viral RNA by polyacrylamide gel electrophoresis permitted the characterisation of 170 and 194 strains identified. Nine different electropherotypes (A-I) and one mixed infection were observed. The "short" electropherotypes (A-E) were predominant and represented 140 strains (82.4%), and the "long" electropherotypes (F-I and M) represented 30 strains (17.6%). The "short" electropherotype A (cafb) was the most frequent in our environment (45.3% of cases) and was predominant during the first 14 months of the study. The "long" electropherotype F (bbea) appeared in July 1990 and was predominant during the last three months. Among these children with diarrhoea, the presence of rotavirus was significantly associated with vomiting, fever, and moderate to severe dehydration. However, no significant differences in the occurrence of these symptoms were found between the "short" and "long" electropherotypes

Nucleotide sequence of SHV-2 beta-lactamase gene.

The nucleotide sequence of plasmid-mediated beta-lactamase SHV-2 from Salmonella typhimurium (SHV-2pHT1) was determined. The gene was very similar to chromosomally encoded beta-lactamase LEN-1 of Klebsiella pneumoniae. Compared with the sequence of the Escherichia coli SHV-2 enzyme (SHV-2E.coli) obtained by protein sequencing, the deduced amino acid sequence of SHV-2pHT1 differed by three amino acid substitutions

[Macrophage activation syndrome and dysgammaglobulinemia. Role of the Epstein-Barr virus].

International audienceThe case of a five-year-old boy with macrophage activation syndrome and Epstein-Barr virus infection is reported. Several unusual features were found, including an early major increase in IgA levels, persistent oligoclonal gammapathy, and delayed development of anti-EA antibodies accompanied with an increase in anti-VCA antibodies. Despite the negative family history, an immune deficit and Purilo syndrome are discussed as possible diagnoses in this child

The effect of trypsin on the growth in vitro of adenoviruses present in faeces.

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