Predominance of rotavirus G9 genotype in children hospitalized for rotavirus gastroenteritis in Belgium during 1999-2003.
BACKGROUND
Group A rotavirus genotypes G1, G2, G3 and G4 are the main etiological agents of infantile diarrhea. The G9 rotavirus has recently emerged as a fifth important genotype all over the world.


OBJECTIVE
To characterize the VP7 gene of group A rotaviruses from gastroenteritis patients admitted to the Gasthuisberg University Hospital, Leuven, Belgium, during 1999-2003.


METHODS
Rotavirus antigen was detected in stool specimens using an enzyme immunoassay. G-typing was performed by reverse transcriptase polymerase chain reaction (RT-PCR) amplification and sequencing of the complete VP7 gene.


RESULTS
The genotype distribution varied markedly over the four rotavirus years in Belgium. In the 1999-2000 rotavirus year, G1 was the predominating type (72%), and G9 was present in 5% of the rotavirus-positive patients. In the 2000-2001 and 2002-2003 years, G9 appeared as the dominating strain (45% and 53%, respectively). In the 2001-2002 year, between two G9 epidemic years, G1 was dominating (66%) but G9 was still present in 24%. All the G9 isolates were combined with P[8] and shared a high gene sequence similarity (<3% sequence divergence on the nucleotide and amino acid level). Phylogenetic analysis of the VP7 genes revealed that our Belgian G9 strains clustered together with recent G9 strains from all over the world, distinct from the prototype G9 strains isolated in the 1980s.


CONCLUSIONS
Our study indicates that although the first introduction of G9 isolates in the Belgian population was recorded in 1997, G9 strains were able to establish themselves quickly as the predominant genotype. The emergence of G9 as an important pathogen in both developing as industrialized countries necessitates the urgent consideration of the G9 moiety in rotavirus vaccines.
Rahman
Mustafizur
M
Laboratory of Clinical and Epidemiological Virology, Department of Microbiology and Immunology, Rega Institute for Medical Research, Minderbroedersstraat 10, University Hospital Gasthuisberg, University of Leuven, B-3000 Leuven, Belgium.
Matthijnssens
Jelle
J
Goegebuer
Truus
T
De Leener
Karolien
K
Vanderwegen
Lieve
L
van der Donck
Ingrid
I
Van Hoovels
Lieve
L
De Vos
Sofie
S
Azim
Tasnim
T
Van Ranst
Marc
M
D000956:Antigens, Viral / Q000235:genetics*; D001530:Belgium / Q000453:epidemiology; D036022:Capsid Proteins / Q000235:genetics*; D002675:Child, Preschool; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D005838:Genotype; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D012401:Rotavirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000453:epidemiology* / Q000821:virology; D017422:Sequence Analysis, DNA
D000956:Antigens, Viral; D036022:Capsid Proteins; C050779:VP7 protein, Rotavirus