Hemagglutinin Gene Clade 3C.2a Influenza A(H3N2) Viruses, Alachua County, Florida, USA, 2014–15

Collection of Viable Aerosolized Influenza Virus and Other Respiratory Viruses in a Student Health Care Center through Water-Based Condensation Growth

“…Sequence data analyses revealed the H1N1 viruses belonged to HA subclade 6B.1, based on criteria mentioned in reference 17 ; the results are presented in Text S1 and Table S4 for the reference strains and other recent local H1N1 viruses we isolated from humans or from other air samplings in other studies. Similar analyses that were performed as outlined in reference 18 indicated that the influenza H3N2 viruses belonged to HA clade subclade 3C.2a. These viruses have amino acid changes at major immunogenic epitopes of the hemagglutinin (HA) protein ( Table S5 ) and neuraminidase (NA) proteins ( Table S5 ) relative to the vaccine strain.…”

“…The HA protein of 3C.2 viruses contains the amino acid substitutions N145S in HA1 and D160N in HA2, whereas subclade 3C.2a viruses contain the following amino acid substitutions at the major antigenic epitopes of HA1: N144S (resulting in loss of a potential glycosylation site), N145S, F159Y, and K160T (in the majority of viruses, these changes result in the gain of a potential glycosylation site), and N225D. Subclade 3C.2a viruses also contain (at other epitopes) L3I and Q311H in HA1 and D160N in HA2 ( 18 , 28 ). The H3N2 viruses of our study were HA subclade 3C.2a ( Table S5 ) and also had amino acid changes in their NA protein ( Table S5 ).…”

Drifted Influenza A and B Viruses Collected by a Water-Based Condensation Growth Air Sampler in a Student Health Care Center during an Influenza Outbreak

“…Both pdmH1N1 and H3N2 IFV A viruses were recovered, as was Victoria lineage IFV B virus. Sanger sequencing of influenza A virus genomic segments 4 (hemagglutinin [HA] gene), 6 (neuraminidase [NA] gene), and 7 (matrix [M2 and M1] genes) and influenza B virus segments 4 (HA gene), 6 (NB glycoprotein [NB] and NA genes), and 7 (matrix protein 1 [M1] and BM2 genes) was accomplished according to previously described methods (1, 6, 7). …”

“…Sequencing revealed that the pdmH1N1 viruses belonged to hemagglutinin (HA) subclade 6B.1 (8–10), the H3N2 viruses belonged to HA clade subclade 3C.2a (7, 8), and the IFV B virus was a Victoria lineage clade 1A virus (11). Of interest, the viruses we isolated differ from those of the trivalent Northern Hemisphere influenza virus vaccines for 2015 to 2016, which contained a clade 1 pdmH1N1, A/California/7/2009 (H1N1); a clade 3C.3a H3N2, A/Switzerland/9715293/2013 (H3N2); and a clade 3 Yamagata-lineage IFV B (a B/Phuket/3073/2013) virus.…”

Surveillance of upper respiratory infections using a new multiplex PCR assay compared to conventional methods during the influenza season in Taiwan

“…Viruses in subclade 3C.2a have predominated in most regions of the world in recent years, and viruses with a further change N171K in the HA1 gene are referred to as subclade 3C.2a1 (Harvala et al, 2017;World Health Organization, 2016; European Centre for Disease Prevention and Control (ECDC), 2016). Antigenic characterization of these 3C.2a viruses continues to be technically challenging due to their low or undetectable hemagglutination activity, as described in many studies (Lednicky et al, 2016;Lin et al, 2017;Skowronski et al, 2016). In Taiwan, these viruses were first detected in early 2016.…”