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Influenza viruses resistant to oseltamivir, news and updates

Re: Influenza viruses resistant to oseltamivir, news and updates

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H1N1 Tamiflu Resistance at 100% In Pennsylvania
Recombinomics Commentary 19:17
December 30, 2008

The oseltamivir testing of H1N1 in Pennsylvania is detailed in the week 51 PA report Seven samples are being tested and the first two have already been H274Y confirmed. They are almost certainly A/Pennsylvania/08/2008 and A/Pennsylvania/09/2008, which were isolated on October 13 and November 2, respectively. One positive is in the northwest corner of the state in Erie county, while the other is in the southeast corner in Bucks county. The five pending samples are from the east, as well as north and south central. It is likely that all five will be H274Y positive based on the sequences from the first two tested.

The week 51 CDC report gives test results on 65 H1N1 isolates. 64 are H274Y positive. The only oseltamivir sensitive case was a clade IIC isolate that was included in the report on the first 2 H1N1 positives. Thus, all 63 tested since the first report have been H274Y positive. The results from Canada were similar. Although the National Labs in Winnipeg had only tested three H1N1 isolates, British Columbia reported results for 14 and all 17 Canadian H1N1 isolate were also positive. In Europe, all reported H1N1 results have been H274Y, except one early clade IIC isolate from England.

Sequences from the early isolates in the US have been released by the CDC, confirming that the one sensitive isolate was clade IIC and the remaining isolates were clade IIB and contained HA A193T. The same change was found in the dominant H1N1 in South Africa, signaling its role in widespread dominance of H1N1 with H274Y.

The US sequences were from isolates in Hawaii, Texas, Pennsylvania, and Wisconsin, further demonstrating that this A193T sub-clade is widespread. Some state agencies are still citing the low number of H1N1 isolates tested as a lack of evidence that near term H1N1 isolates will have H274Y. However, the sequence data , as well as frequencies in the US, Canada, and Europe suggest that H1N1 in these areas will have H274Y in NA and A193T in HA.

In countries where H1N1 is dominant, like the United States and Canada, advisories on oseltamivir usage will be issued.


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Re: Influenza viruses resistant to oseltamivir, news and updates

The seven positive specimens identified by
the DHMH lab have been typed as influenza
A (4, 57%) and influenza B (3, 43%).
To date, the CDC laboratory has identified
two as type A (H1N1) Brisbane-like and
another as type B Florida-like. Both strains​
are​
components of this season?s influenza
vaccine. The type A (H1N1) isolate was
found to be resistant to Oseltamivir
(Tamiflu ?) but sensitive to Adamantanes
and Zanamivir.
Interim guidelines on the
use of antivirals for influenza can be

found at
http://tinyurl.com/cdcinterim.

http://www.edcp.org/influenza/pdf/week-52.pdf
 
Re: Influenza viruses resistant to oseltamivir, news and updates

William A. Hinton State Laboratory Institute
2008 - 2009 Season
(Oct. 10 - Dec. 22, 2008)
Week A(H1) A(H3) A(Unk) B Total #
Tested
Total #
Positive % Positive
40 0 0 0 0 0 0 n/a
41 0 0 0 0 1 0 0
42 0 0 0 0 1 0 0
43 0 0 0 0 3 0 0


44 0
1 0 0 1 1 100

45 0 0 0 0 3 0 0
46 0 0 0 0 4 0 0
47


2 0 0 0 6 2 33

48 0


1 0 0 3 1 33

49 0 0 0 0 1 0 0
50


1 1 0 1 8 3 38

51


1 0 0 0 1 1 100

Total:


4 3 0 1 32 8 25

Antiviral Resistance Testing at the Centers for Disease Control and Prevention
Three H1N1 specimens have been tested for antiviral resistance by CDC: all three were resistant to oseltamivir and sensitive to zanamivir and the adamantanes.

One H3N2 specimen has been tested for antiviral resistance by CDC: it was resistant to the adamantanes and was sensitive to oseltamivir and zanamivir.

 
Re: Influenza viruses resistant to oseltamivir, news and updates

http://www.michigan.gov/documents/MIFluFocus_1_5_06_146893_7.pdf

Michigan Antiviral Resistance Data: [FONT=Arial,Arial][FONT=Arial,Arial]One influenza A (H1N1) virus from the MDCH Bureau of Laboratories has been tested for antiviral resistance at CDC for the 2008-2009 influenza season. This virus was resistant to oseltamivir (Tamiflu?) and sensitive to zanamivir, amantadine and rimantadine. This case was a child from Oakland County who was seen on an outpatient basis and has recovered.
[/FONT]
[/FONT]
 
Re: Influenza viruses resistant to oseltamivir, news and updates

first public occurrance of H275Y in current H1N1:

A/Paris/1341/2007(H1N1) from 2007/11/12


no sequences with H275Y from Asia, Summer/Autumn 2007 ?

also Hawaii/28/07 , but not the same NA as in Europe (MRCAD early 2007?)


the most recent common ancestor of all the resistant H1N1
viruses last season (except those with 827T in NA ==> the majority of 123)
seems to be from autumn 2007, Europe and USA in 2007

but what/where was the earliest occurrence ?
 
Re: Influenza viruses resistant to oseltamivir, news and updates

first public occurrance of H275Y in current H1N1:

A/Paris/1341/2007(H1N1) from 2007/11/12


no sequences with H275Y from Asia, Summer/Autumn 2007 ?

also Hawaii/28/07 , but not the same NA as in Europe (MRCAD early 2007?)


the most recent common ancestor of all the resistant H1N1
viruses last season (except those with 827T in NA ==> the majority of 123)
seems to be from autumn 2007, Europe and USA in 2007

but what/where was the earliest occurrence ?
H274Y is now in clade 2B and clade 2C and key changes go well beyond (and before) any MRCAD
 
Re: Influenza viruses resistant to oseltamivir, news and updates

World Health Organization: Influenza A(H1N1) virus resistance to oseltamivir - 2008/2009 influenza season, northern hemisphere (1/6/2009)

Influenza A(H1N1) virus resistance to oseltamivir - 2008/2009 influenza season, northern hemisphere

30 December 2008

[Original PDF Document at LINK. EDITED.]


During the weeks 41?44 (5 October ? 1 November), influenza activity remained low.

Sporadic influenza activity was detected in Belarus (A), Belgium (B), Canada (A,B), Chile (H1, B), China (H1), China, Hong Kong Special Administrative Region (H1,H3, B), Denmark (H3), Finland (A), Japan (H1,H3), Kenya (A), Mexico (B), Poland (A), Russian Federation (H1, H3, B), the United Kingdom of Great Britain and Northern Ireland (H1,H3) and the United States of America (A, B).

WHO has received several reports from National Influenza Centres (NIC) in the northern hemisphere regarding influenza A(H1N1) virus resistance to oseltamivir for the beginning of 2008/2009 influenza season (week 41-44).

Among A(H1N1) viruses tested, 13 of 14 in the United Kingdom,1 of 1 in Israel, 1 of 1 in Ghana and 1 of 1 in Canada had the specific neuraminidase mutation (H275Y; numbered according to N1 sequence) associated with oseltamivir resistance.

Japan also reported that 13 of 14 A(H1N1) viruses tested were resistant*.

WHO is collecting global data about this phenomenon from multiple laboratories participating in Global Influenza Surveillance Network.

Data from European countries participating in EISS were provided by the EISS and the VirGil project.

This summary table will be updated every four weeks.

Oseltamivir resistance results were based on phenotypic and/or genotypic analyses.

*The National Influenza Centre in Japan reported that 6 of the 14 viruses were obtained from two outbreaks in geographically separated prefectures (3 from a kindergarten in Yamaguchi Prefecture and 3 from a primary school in Miyagi Prefecture).


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