Co-circulation of two genetically distinct sub-groups of A/H3N2 influenza strains during the 2006-2007 epidemic season in Corsica Island, France.
BACKGROUND
Influenza virus is one of the major viral respiratory pathogens infecting human beings.


OBJECTIVE
To determine the influenza A virus variants responsible for the 2006-2007 epidemic season in Corsica Island, France.


METHODS
Of 134 nasal samples of adult patients tested by culture and RT-PCR assays, 85 influenza A strains were identified; 81 (95%) were sub-typed as A/H3N2 and 4 (5%) were sub-typed as A/H1N1.


RESULTS
All of the HA sequences of the A/H3N2 viruses circulating in Corsica Island appeared to be closely related to the A/Wisconsin/67/2005 vaccine strain and segregated into two sub-groups that were genetically distinct from other viruses circulating in other countries during 2006/2007. One of these sub-groups was distinguished by the substitution H156Q whereas the second demonstrated at least one of the 3 other additional mutations (R142G, L157S and K173E) common to the HA1 sequence of A/Nepal/921/2006 reference strain. Among the 14 strains of this second sub-group, 10 viral strains had been isolated from vaccinated adult patients.


CONCLUSIONS
These findings suggest that a prospective analysis of the HA sequences of influenza isolates may allow an early detection of newly evolved variants with potential epidemiological inference.
Falchi
Alessandra
A
INSERM, U707, Paris, France. falchi@u707.jussieu.fr
Varesi
Laurent
L
Arena
Christophe
C
Leveque
Nicolas
N
Renois
Fanny
F
Blanchon
Thierry
T
Amoros
Jean Pierre
JP
Andreoletti
Laurent
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019943:Amino Acid Substitution; D002648:Child; D002675:Child, Preschool; D005260:Female; D005602:France / Q000453:epidemiology; D005838:Genotype; D006389:Hemagglutinins, Viral / Q000235:genetics; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000302:isolation & purification; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D017422:Sequence Analysis, DNA; D055815:Young Adult
D006389:Hemagglutinins, Viral; C458881:hemagglutinin fusogenic peptide, influenza virus