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Influenza viruses circulating in Thailand in 2004 and 2005

Waicharoen S, Thawatsupha P, Chittaganpitch M, Maneewong P, Thanadachakul T, Sawanpanyalert P

Jpn J Infect Dis, 2008 Jul;61(4):321-3.
PMID: 18653981

Determining the local circulating strain of influenza is essential to prevent and control epidemics. In the years 2004 and 2005, the National Influenza Center of Thailand received 3,854 and 3,834 specimens, respectively, from patients throughout the country, including submissions from 4 established influenza surveillance sentinel sites. In 2004, of 539 influenza-positive specimens, 461 were positive for influenza A and 78 were positive for influenza B by isolation. Influenza A subtyping revealed that 249, 197, and 15 isolates were H1N1, H3N2, and H5N1, respectively. In 2005, of 748 influenza-positive specimens, 492 were influenza A and the remaining 256 were influenza B. The results of influenza A subtyping indicated that 55, 437, and 5 isolates were H1N1, H3N2, and H5N1. All isolated strains of subtype H1N1 were A/New Caledonia/20/99-like. The isolated strains of H3N2 were A/Fujian/411/2002-like in the first half of the year 2004, while those in the latter half of 2004 gradually drifted to a mixture of A/Wellington/1/2004-like, A/California/7/2004-like, and A/Wisconsin/67/2005-like, and this mixture continued through the end of 2005. The influenza B strains were B/Sichuan/379/99-like, B/Hong Kong/330/2001-like, B/Shanghai/361/2002-like and B/Malaysia/2506/2004-like. The strains circulating in the years 2004 and 2005 were antigenically similar to the vaccine formulas recommended in the same period by WHO. Our results underscore that local influenza surveillance plays an important role in responding to epidemics and potential pandemics.

Matched MeSH terms: Influenza A Virus, H3N2 Subtype/isolation & purification
Sulfated membrane adsorbers for economic pseudo-affinity capture of influenza virus particles

Opitz L, Lehmann S, Reichl U, Wolff MW

Biotechnol Bioeng, 2009 Aug 15;103(6):1144-54.
PMID: 19449393 DOI: 10.1002/bit.22345

Strategies to control outbreaks of influenza, a contagious respiratory tract disease, are focused mainly on prophylactic vaccinations in conjunction with antiviral medications. Currently, several mammalian cell culture-based influenza vaccine production processes are being established, such as the technologies introduced by Novartis Behring (Optaflu) or Baxter International Inc. (Celvapan). Downstream processing of influenza virus vaccines from cell culture supernatant can be performed by adsorbing virions onto sulfated column chromatography beads, such as Cellufine sulfate. This study focused on the development of a sulfated cellulose membrane (SCM) chromatography unit operation to capture cell culture-derived influenza viruses. The advantages of the novel method were demonstrated for the Madin Darby canine kidney (MDCK) cell-derived influenza virus A/Puerto Rico/8/34 (H1N1). Furthermore, the SCM-adsorbers were compared directly to column-based Cellufine sulfate and commercially available cation-exchange membrane adsorbers. Sulfated cellulose membrane adsorbers showed high viral product recoveries. In addition, the SCM-capture step resulted in a higher reduction of dsDNA compared to the tested cation-exchange membrane adsorbers. The productivity of the SCM-based unit operation could be significantly improved by a 30-fold increase in volumetric flow rate during adsorption compared to the bead-based capture method. The higher flow rate even further reduced the level of contaminating dsDNA by about twofold. The reproducibility and general applicability of the developed unit operation were demonstrated for two further MDCK cell-derived influenza virus strains: A/Wisconsin/67/2005 (H3N2) and B/Malaysia/2506/2004. Overall, SCM-adsorbers represent a powerful and economically favorable alternative for influenza virus capture over conventional methods using Cellufine sulfate.

Matched MeSH terms: Influenza A Virus, H3N2 Subtype/isolation & purification*
[The 2005-2006 influenza season in the Netherlands and the vaccine composition for the 2006-2007 season]

Rimmelzwaan GF, de Jong JC, Donker GA, Meijer A, Fouchier RA, Osterhaus AD

Ned Tijdschr Geneeskd, 2006 Oct 7;150(40):2209-14.
PMID: 17061434

The first sign of influenza activity in the Netherlands during the 2005-2006 influenza season was the isolation of influenza viruses in the last week of 2005. From Week 1 of 2006 onwards, an increase in clinical influenza activity was also observed that did not return to baseline levels until Week 15. Two waves of influenza activity were observed with peak incidences of 13.8 and 9.8 influenza-like illnesses per 10,000 inhabitants on Weeks 7 and 12, respectively. The first wave of influenza was caused primarily by influenza B viruses, whereas the second wave was caused predominantly by influenza A/H3N2 viruses. The influenza B viruses appeared to belong to two different phylogenetic lineages and were antigenically distinguishable from the vaccine strain. The isolated influenza A/H3N2 viruses were closely related to the vaccine strain for this subtype and only minor antigenic differences with the vaccine strain were observed for a limited number of isolates. Only a small number of influenza A/H1N1 viruses were isolated, which all closely resembled the H1N1 vaccine strain. For the 2006-2007 influenza season, the World Health Organization has recommended the following vaccine composition: A/Wisconsin/67/05 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Malaysia/2506/05.

Matched MeSH terms: Influenza A Virus, H3N2 Subtype/isolation & purification
Fulltext Epidemiological and virological characteristics of influenza viruses circulating in Cambodia from 2009 to 2011

Horm SV, Mardy S, Rith S, Ly S, Heng S, Vong S, et al.

PLoS One, 2014;9(10):e110713.
PMID: 25340711 DOI: 10.1371/journal.pone.0110713

BACKGROUND: The Cambodian National Influenza Center (NIC) monitored and characterized circulating influenza strains from 2009 to 2011.
METHODOLOGY/PRINCIPAL FINDINGS: Sentinel and study sites collected nasopharyngeal specimens for diagnostic detection, virus isolation, antigenic characterization, sequencing and antiviral susceptibility analysis from patients who fulfilled case definitions for influenza-like illness, acute lower respiratory infections and event-based surveillance. Each year in Cambodia, influenza viruses were detected mainly from June to November, during the rainy season. Antigenic analysis show that A/H1N1pdm09 isolates belonged to the A/California/7/2009-like group. Circulating A/H3N2 strains were A/Brisbane/10/2007-like in 2009 before drifting to A/Perth/16/2009-like in 2010 and 2011. The Cambodian influenza B isolates from 2009 to 2011 all belonged to the B/Victoria lineage represented by the vaccine strains B/Brisbane/60/2008 and B/Malaysia/2506/2004. Sequences of the M2 gene obtained from representative 2009-2011 A/H3N2 and A/H1N1pdm09 strains all contained the S31N mutation associated with adamantanes resistance except for one A/H1N1pdm09 strain isolated in 2011 that lacked this mutation. No reduction in the susceptibility to neuraminidase inhibitors was observed among the influenza viruses circulating from 2009 to 2011. Phylogenetic analysis revealed that A/H3N2 strains clustered each year to a distinct group while most A/H1N1pdm09 isolates belonged to the S203T clade.
CONCLUSIONS/SIGNIFICANCE: In Cambodia, from 2009 to 2011, influenza activity occurred throughout the year with peak seasonality during the rainy season from June to November. Seasonal influenza epidemics were due to multiple genetically distinct viruses, even though all of the isolates were antigenically similar to the reference vaccine strains. The drug susceptibility profile of Cambodian influenza strains revealed that neuraminidase inhibitors would be the drug of choice for influenza treatment and chemoprophylaxis in Cambodia, as adamantanes are no longer expected to be effective.

Matched MeSH terms: Influenza A Virus, H3N2 Subtype/isolation & purification
Fulltext Influenza outbreaks during World Youth Day 2008 mass gathering

Blyth CC, Foo H, van Hal SJ, Hurt AC, Barr IG, McPhie K, et al.

Emerg Infect Dis, 2010 May;16(5):809-15.
PMID: 20409371 DOI: 10.3201/eid1605.091136

Influenza outbreaks during mass gatherings have been rarely described, and detailed virologic assessment is lacking. An influenza outbreak occurred during World Youth Day in Sydney, Australia, July 2008 (WYD2008). We assessed epidemiologic data and respiratory samples collected from attendees who sought treatment for influenza-like illness at emergency clinics in Sydney during this outbreak. Isolated influenza viruses were compared with seasonal influenza viruses from the 2008 influenza season. From 100 infected attendees, numerous strains were identified: oseltamivir-resistant influenza A (H1N1) viruses, oseltamivir-sensitive influenza A (H1N1) viruses, influenza A (H3N2) viruses, and strains from both influenza B lineages (B/Florida/4/2006-like and B/Malaysia/2506/2004-like). Novel viruses were introduced, and pre-WYD2008 seasonal viruses were amplified. Viruses isolated at mass gatherings can have substantial, complex, and unpredictable effects on community influenza activity. Greater flexibility by public health authorities and hospitals is required to appropriately manage and contain these outbreaks.

Matched MeSH terms: Influenza A Virus, H3N2 Subtype/isolation & purification
Fulltext Component-specific effectiveness of trivalent influenza vaccine as monitored through a sentinel surveillance network in Canada, 2006-2007

Skowronski DM, De Serres G, Dickinson J, Petric M, Mak A, Fonseca K, et al.

J Infect Dis, 2009 Jan 15;199(2):168-79.
PMID: 19086914 DOI: 10.1086/595862

Trivalent inactivated influenza vaccine (TIV) is reformulated annually to contain representative strains of 2 influenza A subtypes (H1N1 and H3N2) and 1 B lineage (Yamagata or Victoria). We describe a sentinel surveillance approach to link influenza variant detection with component-specific vaccine effectiveness (VE) estimation.

Matched MeSH terms: Influenza A Virus, H3N2 Subtype/isolation & purification