tetano
Editor, Senior Moderator
J Med Virol. 2013 Nov;85(11):1871-7. doi: 10.1002/jmv.23700.
Reduced replication capacity of influenza A(H1N1)pdm09 virus during the 2010-2011 winter season in Tottori, Japan.
Tsuneki A, Itagaki A, Tsuchie H, Tokuhara M, Okada T, Narai S, Kasagi M, Tanaka K, Kageyama S.
Source
Division of Virology, Department of Microbiology and Immunology, Tottori University Faculty of Medicine, Yonago City, Japan; Tottori Infectious Diseases Forum, Tottori Prefecture, Japan.
Abstract
A novel swine-origin influenza A(H1N1)pdm09 virus has been circulating in humans since March-April, 2009. The 2009-2010 epidemic involved predominantly a single subtype of A(H1N1)pdm09 (at 96%, 46/48) in the sentinel sites of this study. However, A(H1N1)pdm09 started to circulate together with other type/subtype (49%, 33/68) at the first peak in the next epidemic season in 2010-2011: A(H1N1)pdm09/A(H3N2) (9%, 6/68), A(H1N1)pdm09/B (35%, 24/68), and A(H1N1)pdm09/A(H3N2)/B (4%, 3/68). Single infection of A(H1N1)pdm09 became a rare event (8%, 5/65) at the second peak of the same season in 2010-2011 compared with that at the first peak (50%, 34/68). Concurrently with this decline, single infections of others, A(H3N2) or B, became evident (6%, 4/65; 14%, 9/65, respectively). Triple infections were more common (29%, 19/65) at the second peak than at the first peak (4%). The A(H1N1)pdm09 detected in 2010-2011 produced less virus upon 72 hr of incubation in vitro after the inoculations at 10(4) and 3,300 copies/ml (2.3 ? 10(9) and 2.3 ? 10(9) copies/ml on average) than that in 2009-2010 (3.7 ? 10(9) and 1.3 ? 10(10) copies/ml on average; P < 0.05 by ANOVA test), respectively. As described above, the replication capacity of A(H1N1)pdm09 seems to have deteriorated in the 2010-2011 season presumably due to substantial herd immunity and allowed the existence of other type/subtype. These results suggest that assessment of replication capacity is indispensable for analysis of influenza epidemics. J Med. Virol. 85:1871-1877, 2013. ? 2013 Wiley Periodicals, Inc.
? 2013 Wiley Periodicals, Inc.
KEYWORDS:
A(H3N2), B, RNA levels, co-circulations, surveillance
PMID:
23983181
[PubMed - in process]
http://www.ncbi.nlm.nih.gov/pubmed/23983181
Reduced replication capacity of influenza A(H1N1)pdm09 virus during the 2010-2011 winter season in Tottori, Japan.
Tsuneki A, Itagaki A, Tsuchie H, Tokuhara M, Okada T, Narai S, Kasagi M, Tanaka K, Kageyama S.
Source
Division of Virology, Department of Microbiology and Immunology, Tottori University Faculty of Medicine, Yonago City, Japan; Tottori Infectious Diseases Forum, Tottori Prefecture, Japan.
Abstract
A novel swine-origin influenza A(H1N1)pdm09 virus has been circulating in humans since March-April, 2009. The 2009-2010 epidemic involved predominantly a single subtype of A(H1N1)pdm09 (at 96%, 46/48) in the sentinel sites of this study. However, A(H1N1)pdm09 started to circulate together with other type/subtype (49%, 33/68) at the first peak in the next epidemic season in 2010-2011: A(H1N1)pdm09/A(H3N2) (9%, 6/68), A(H1N1)pdm09/B (35%, 24/68), and A(H1N1)pdm09/A(H3N2)/B (4%, 3/68). Single infection of A(H1N1)pdm09 became a rare event (8%, 5/65) at the second peak of the same season in 2010-2011 compared with that at the first peak (50%, 34/68). Concurrently with this decline, single infections of others, A(H3N2) or B, became evident (6%, 4/65; 14%, 9/65, respectively). Triple infections were more common (29%, 19/65) at the second peak than at the first peak (4%). The A(H1N1)pdm09 detected in 2010-2011 produced less virus upon 72 hr of incubation in vitro after the inoculations at 10(4) and 3,300 copies/ml (2.3 ? 10(9) and 2.3 ? 10(9) copies/ml on average) than that in 2009-2010 (3.7 ? 10(9) and 1.3 ? 10(10) copies/ml on average; P < 0.05 by ANOVA test), respectively. As described above, the replication capacity of A(H1N1)pdm09 seems to have deteriorated in the 2010-2011 season presumably due to substantial herd immunity and allowed the existence of other type/subtype. These results suggest that assessment of replication capacity is indispensable for analysis of influenza epidemics. J Med. Virol. 85:1871-1877, 2013. ? 2013 Wiley Periodicals, Inc.
? 2013 Wiley Periodicals, Inc.
KEYWORDS:
A(H3N2), B, RNA levels, co-circulations, surveillance
PMID:
23983181
[PubMed - in process]
http://www.ncbi.nlm.nih.gov/pubmed/23983181