Influenza A (H3N2) outbreak, Nepal.
In July 2004, an outbreak of influenza A (H3N2) was detected at 3 Bhutanese refugee camps in southeastern Nepal. Hemagglutination inhibition showed that approximately 40% of the viruses from this outbreak were antigenically distinct from the A/Wyoming/3/03 vaccine strain. Four amino acid differences were observed in most of the 26 isolates compared with the A/Wyoming/3/2003 vaccine strain. All 4 substitutions are located within or adjacent to known antibody-binding sites. Several isolates showed a lysine-to-asparagine substitution at position 145 (K145N) in the hemagglutinin molecule, which may be noteworthy since position 145 is located within a glycosylation site and adjacent to an antibody-binding site. H3N2 viruses continue to drift from the vaccine strain and may remain as the dominant strains during the 2005-2006 influenza season. Thus, the 2005-2006 Northern Hemisphere vaccine strain was changed to A/California/7/2004, a virus with all 4 amino acid substitutions observed in these Nepalese isolates.
Daum
Luke T
LT
Air Force Institute for Operational Health, Brooks City Base, San Antonio, Texas 78235, USA. Luke.Daum@brooks.af.mil
Shaw
Michael W
MW
Klimov
Alexander I
AI
Canas
Linda C
LC
Macias
Elizabeth A
EA
Niemeyer
Debra
D
Chambers
James P
JP
Renthal
Robert
R
Shrestha
Sanjaya K
SK
Acharya
Ramesh P
RP
Huzdar
Shankar P
SP
Rimal
Nirmal
N
Myint
Khin S
KS
Gould
Philip
P
D000595:Amino Acid Sequence; D000940:Antigenic Variation / Q000235:genetics*; D002648:Child; D004196:Disease Outbreaks; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006388:Hemagglutinins / Q000235:genetics; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009390:Nepal / Q000453:epidemiology; D010802:Phylogeny; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D006388:Hemagglutinins; D012367:RNA, Viral