title: Characterisation of rotavirus strains among hospitalised and non-hospitalised children in Guinea-Bissau, 2002 A high frequency of mixed infections with serotype G8.
abstract: BACKGROUND
  In a previous community-based cohort study in Guinea-Bissau from 1996 to 1998, characterisation of rotavirus strains showed a high frequency of less common genotypes such as G8 and G9 and a high proportion of mixed infections.
  
  
  OBJECTIVE
  In the present study, we examined the prevalence of rotavirus genotypes among 81 hospitalised and 23 non-hospitalised Guinean children with rotavirus associated diarrhoea during the 2002 seasonal rotavirus outbreak. G- and P-types were determined in a two-step procedure using reverse transcription followed by a standard multiplex PCR. The multiplex PCR for G-types was furthermore supplemented with a single locus PCR including the MW8 primer for the G8-genotype.
  
  
  RESULTS
  The dual infection G2/P[4]P[6] (24%) appeared to be the most frequent cause of rotavirus infections followed by G2P[4] (19%), G2P[6] (16%) and G8P[6] (13%). Overall 38% of the infections were mixed and 18% of the samples had the genotype G8. However, by subjecting all samples and not only the strains, which according to the standard multiplex PCR procedure were non-typeable, to a single locus G8-PCR, we found that the genotype G8 appeared in 62% of the infections, either as a single G-strain or in combination with other G-types, especially G2. Including these results, more than 63% of infections emerged as mixed. Neither genotype (including the presence of G8) nor the presence of mixed infections, seem to influence the severity of the rotavirus infection.
  
  
  CONCLUSIONS
  We found a high frequency of mixed infections especially due to G8-genotypes, which might have implications for development of rotavirus vaccine candidates for use in Africa. Our results do not suggest that a single genotype is associated with severity, but the present study is based on a modest number of samples and results should be interpreted with caution.
authors.affiliation: Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark. NMN@ssi.dk
authors.forename: Nete Munk
authors.initials: NM
authors.lastname: Nielsen
authors.forename: Jesper
authors.initials: J
authors.lastname: Eugen-Olsen
authors.forename: Peter
authors.initials: P
authors.lastname: Aaby
authors.forename: Kåre
authors.initials: K
authors.lastname: Mølbak
authors.forename: Amabelia
authors.initials: A
authors.lastname: Rodrigues
authors.forename: Thea Kølsen
authors.initials: TK
authors.lastname: Fischer
mesh_terms: D001483:Base Sequence; D002648:Child; D002673:Child, Hospitalized; D015331:Cohort Studies; D017124:Conserved Sequence; D004196:Disease Outbreaks; D005838:Genotype; D006169:Guinea-Bissau / Q000453:epidemiology; D006801:Humans; D008969:Molecular Sequence Data; D010045:Outpatients; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D012401:Rotavirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012400:Rotavirus Infections / Q000145:classification / Q000453:epidemiology*; D012621:Seasons; D016415:Sequence Alignment; D012703:Serotyping
chemical_list: D012367:RNA, Viral