H3N2 Strain Information

[jeanne]

yesterday appeared an article in promed about a new strain of h3n2 that has the same mutations as the h1n1 strain that is currently spreading.

the people who did the sequencing saw it in long term care patients in canada earlier in april, and then found it in a sample taken from someone returning from mexico.

they conjecture that a second rapidly spreading virus with no immunity might be confusing things in mexico and here in the states.

here is the original article:

archive number 20090505.1679

http://www.promedmail.org/pls/otn/f?p=2400:1001:5350711258283783::NO::F2400_P1001_BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1010,77349

there have been no further reports except to spread these findings. i am looking forward to seeing other researchers sequence some of the flus the population are presenting with., so i have started a new thread to track mention of it.

currently, NewsNow has only one article under h3n2.

[jeanne]

Influenza a (h1n1) - worldwide (11): Coincident h3n2 variation

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Date: Tue 5 May 2009 12:08:07 -0700
From: Danuta Skowronski
<Danuta.Skowronski@bccdc.ca>


Recent mutations away from the 2008-09 influenza vaccine strain among
North American A/H3N2 virus coincident with emergence of novel A/H1N1
--------------------------------------------------------------------------------------------
The BC [British Columbia] Centre for Disease Control (BCCDC) Virology
Laboratory routinely sequences the hemagglutinin (HA) gene from a
sample of influenza viruses submitted each season by community
clinicians, hospitals and care facilities across the province of
British Columbia, Canada.

Until mid-February 2009, amino acid sequences of the HA gene of H3
viruses in BC were virtually identical to the vaccine strain [A/
Brisbane/10/07 (H3N2)], with the exception of a Lys189Gln change at
antigenic site B. In early March 2009, however, we detected
additional differences from the vaccine strain among BC viruses
collected from facility outbreak settings at antigenic site B to
include change from the vaccine strain at Asp160Lys (as well as
Lys189Gln) and at antigenic site D at Val229Ala. These changes were
seen only in viruses from care facility outbreaks and not from
community specimens submitted by our network of sentinel physicians.

After the novel North American influenza A/H1N1 virus was reported
from Mexico as well as California during the 4th week of April 2009,
specimens from returning travelers and others in BC with
influenza-like illness were tested including influenza subtype
determination and sequencing. Among approximately 900 respiratory
specimens submitted to the BCCDC laboratory between 24 Apr 2009 and 3
May 2009, the majority was negative for influenza; an equal number of
influenza A detections were of the H1 or H3 subtype.
We have sequenced the HA gene of one of the H3 viruses from an ill
traveler returning from Mexico and find it shares the same amino acid
changes noted above.

These amino acid substitutions do not fulfill the criteria proposed
by Cox as corresponding to meaningful antigenic drift (requiring at
least 2 amino acid substitutions at 2 or more defined antigenic sites
A-E)[1] They may, however, signal important evolution in the HA gene.
During late March and early April 2009 we reported an unexpected
number of late-season care facility outbreaks due to H3 influenza. We
should thus remain vigilant for further H3N2 evolution and reduced
vaccine relatedness since A/Brisbane/10/07(H3N2) has been retained as
the proposed vaccine component for both the 2009 southern and 2009-10
northern hemisphere influenza seasons. Ongoing gene sequence analysis
of H3 viruses from other countries would be informative. In BC, these
H3 mutations arose sometime in early March 2009 and we observe at
least one returning traveler to have likely acquired illness due to
this virus in Mexico (specimen collected in BC 26 Apr 2009). We thus
also wonder to what extent the profile of influenza-like illness
initially reported from mid-March in Mexico may in part be attributed
to this H3N2 variant in addition to emergence of the novel A/H1N1 virus.

Reference:
----------
[1] Cox NJ, Bender CA. The molecular epidemiology of influenza
viruses. S/eminars in /VIROLOGY 1995; 6:359-370.

Authors:
Danuta M Skowronski MD, MHSc, FRCPC, Tracy Chan BSc, Naveed Z Janjua
MD, DrPH, Travis Hottes MSc, Annie Mak BSc, Martin Petric PhD, FCCM,
Mel Krajden MD, FRCPC, Patrick Tang MD, PhD, FRCPC, David Patrick MD,
MHSc, FRCPC, Robert Brunham MD, FRCPC.

At: The BC Centre for Disease Control Provincial Laboratories and
Epidemiology Services

--
Communicated by:
Phil Temples
<phil@temples.com>

[The novel observations reported above reveal the occurrence of
progressive variation in the HA gene of H3N2-type seasonal influenza
virus which if maintained may have consequences for the outcome of
the next seasonal influenza vaccination programme. More intriguing is
the observation that the same novel mutational changes were detected
among viruses isolated from patients in care facilities in Canada as
in a virus isolated from a traveler from Mexico. The authors suggest
that the profile of influenza-like illness initially reported from
mid-March 2009 in Mexico may in part be attributed to this H3N2
variant in addition to the emergence of the novel A/H1N1 virus. This
is a matter that merits urgent investigation as it might help to
explain some of the unusual features of the current epidemic. - Mod.CP]

[see also:
Influenza A (H1N1) - worldwide (10): case counts 20090504.1675
Influenza A (H1N1) - worldwide (09) 20090504.1673
Influenza A (H1N1) - worldwide (08): case counts 20090503.1660
Influenza A (H1N1) - worldwide (07) 20090503.1658
Influenza A (H1N1) - worldwide (06): case counts 20090502.1654
Influenza A (H1N1) - worldwide (05) 20090503.1657
Influenza A (H1N1) - worldwide (04): case counts 20090501.1648
Influenza A (H1N1) - worldwide (03) 20090501.1646
Influenza A (H1N1) - worldwide (02): case counts 20090430.1638
Influenza A (H1N1) - worldwide 20090430.1636
Influenza A (H1N1) "swine flu": worldwide (07), update, pandemic
5 20090429.1622
Influenza A (H1N1) "swine flu": worldwide (06) 20090429.1614
Influenza A (H1N1) "swine flu": worldwide (05) 20090428.1609
Influenza A (H1N1) "swine flu": worldwide (04) 20090428.1601
Influenza A (H1N1) "swine flu": worldwide (03) 20090428.1600
Influenza A (H1N1) "swine flu": Worldwide (02) 20090427.1586
Influenza A (H1N1) "swine flu": Worldwide 20090427.1583
Influenza A (H1N1) virus, human: worldwide 20090426.1577
Influenza A (H1N1) virus, human - New Zealand, susp 20090426.1574
Influenza A (H1N1) virus, human - N America (04) 20090426.1569
Influenza A (H1N1) virus, human - N America (03) 20090426.1566
Influenza A (H1N1) virus, human - N America (02) 20090425.1557
Influenza A (H1N1) virus, human - N America 20090425.1552
Acute respiratory disease - Mexico, swine virus susp 20090424.1546
Influenza A (H1N1) virus, swine, human - USA (02): (CA, TX) 20090424.1541
Influenza A (H1N1) virus, swine, human - USA: (CA) 20090422.1516
Influenza A (H1N1) virus, swine, human - Spain 20090220.0715
2008
----
Influenza A (H1N1) virus, swine, human - USA (TX) 20081125.3715
2007
----
Influenza A (H2N3) virus, swine - USA 20071219.4079
Influenza, swine, human - USA (IA): November 2006 20070108.0077]
........................cp/ejp/dk

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[Shiloh]

Re: h3n2 new strain

Source: http://www.npr.org/blogs/health/2009...ave_cause.html

Second Strain Might Have Caused Some Severe Cases In Mexico, Investigators Say

By Richard Knox

A new discovery from Canada raises the question -- has a new mutation in an ordinary flu virus been causing some of the recent respiratory disease hospitalizations and deaths in Mexico?

It's too soon to tell, but scientists in Vancouver are wondering. They've found two mutations in H3N2, a regular seasonal flu virus that's been circulating in North America since last fall. (The swine flu virus is a type of H1N1.)

The mutations affect a protein called hemagglutinin that sits on the outer coat of Type A flu viruses. That's what the "H" stands for in H1N1, H3N2 and other Type A viruses. (The "N" stands for neuraminidase, another surface protein.)

The new version of H3N2 has shown up in a number of nursing home patients in British Columbia, though not yet in the general community there. And this week the Canadian researchers spotted it when they did a complete genetic analysis of a flu virus that sickened a Canadian traveler who had just returned from Mexico.

This raises the possibility that the traveler became infected in Mexico, says Dr. Robert Brunham, chief of the British Columbia Centre for Disease Control. If so, the H3N2 virus circulating in Mexico may have the same two mutations as those being found in British Columbia patients who haven't been to Mexico .

"In British Columbia, the H3N2 virus causes more severe cases of flu than H1N1 does," Brunham says. "So we wonder if some of the severe cases in Mexico may have been caused by the variant H3N2 virus."

There's another potential implication of the Canadian finding.

Public health officials watch flu viruses closely for mutations that might make new variants of viruses less susceptible to flu vaccines. A strain called H3N2/Brisbane is one of the three components in this year's seasonal flu vaccine -- and it's also in the vaccine now being made for next winter's flu season.

So far the new variation of H3N2 hasn't crossed the threshold of concern for scientists about the effectiveness of next season's vaccine. But, "it only takes one more mutation" to cross that threshold, Brunham says.

But nobody can say yet whether the new H3N2 mutant has been circulating widely in Mexico. That's something researchers really want to find out ASAP.

British Columbian health officials have tested a number of people who have returned from Mexico recently suffering from cold or flu symptoms, along with hundreds of non-travelers. Most didn't have any sort of flu. Among the 10 percent who did test positive for flu, they were split 50-50 between H1N1 and H3N2 types.

However, health officials have so far only done close genetic analysis on one Mexico traveler. So they can't say how many of the others have the new version of H3N2.


8:48 AM ET | 05-06-2009 | permalink

[Shiloh]

Re: h3n2 new strain

Source: http://in.reuters.com/article/health...090507?sp=true

Second strain of flu may complicate picture: study
Thu May 7, 2009 12:49pm IST
By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - A second strain of influenza, one of the seasonal strains, may have mutated and may be complicating the picture in Mexico, Canadian researchers reported on Wednesday.

They have found a strain of the H3N2 virus that appears to have made a shift and could have complicated the flu picture in Mexico, epicenter of an outbreak of a new strain of the H1N1 swine flu virus.

One was seen in a traveler returning from Mexico, the team at the British Columbia Center for Disease Control reported to Pro-MED, an online forum for infectious disease experts. And it may have been involved in an unusually late outbreak of flu in long-term care facilities this year.

The new H1N1 virus has killed at least 42 people in Mexico and two in the United States, has spread globally and brought the world to the brink of a pandemic. It appears to act like seasonal flu but doctors have been confused because it has also killed some young and apparently healthy adults -- not the usual pattern for influenza, which picks off the elderly, chronically ill and very young.

Danuta Skowronski and colleagues said they routinely sequence the hemagglutinin gene from a sample of influenza viruses submitted each season by community doctors, hospitals and care facilities across the province of British Columbia, Canada. Hemagglutinin gives a flu virus the "H" in its name, as in H1N1 or H3N2, and is found on the surface of the virus.

Vaccines target hemagglutinin and when it changes, the vaccine must be changed, too. This year the vaccine targets strains of H3N2 influenza, an H1N1 strain different from the new swine flu strain, and an influenza B strain.

"Until mid-February 2009, amino acid sequences of the hemagglutinin gene of H3 viruses in British Columbia were virtually identical to the vaccine strain," Skowronski wrote.

"In early March 2009, however, we detected additional differences from the vaccine strain among British Columbia viruses collected from facility outbreak settings." They only found these changes in flu samples taken from patients in care facilities.

When news broke of the new H1N1 strain, they ran more tests.

"We have sequenced the hemagglutinin gene of one of the H3 viruses from an ill traveler returning from Mexico and find it shares the same ... changes," they wrote.

"In British Columbia, these H3 mutations arose sometime in early March 2009 and we observe at least one returning traveler to have likely acquired illness due to this virus in Mexico," they wrote.

"We thus also wonder to what extent the profile of influenza-like illness initially reported from mid-March in Mexico may in part be attributed to this H3N2 variant in addition to emergence of the novel A/H1N1 virus."

(Reporting by Maggie Fox, Editing by Sandra Maler)

[jeanne]

H3N2 emerges as second Mexican influenza virus

discussion of canadian findings by mexicans, and a call to sequence samples worldwide.

http://www.clinica.co.uk/news2/may_09/h3n2_emerges_as_second_mexican_influenza_virus

H3N2 emerges as second Mexican influenza virus
Friday 8 May 2009 Bernard Murphy - Editor, International Markets & Investigations


Further evidence has emerged that a second virus was involved in the Mexican influenza epidemic.

The news confirms Clinica's understanding, prompted by Mexican health ministry comments, that a virus other than H1N1 might explain the complex epidemiological picture in Mexico, and how this differs from the rest of the world.

Canadian researchers have discovered that mutations in the seasonal virus strain H3N2 in Canadian samples are linked to the Mexican outbreaks. The changes appear to have occurred between mid-February and early March, ahead of the first reports of unusual influenza activity in Mexico.

"This is a matter that merits urgent investigation, as it might help to explain some of the unusual features of the current epidemic," the team from the British Columbia Centre for Disease Control (BCCDC) have warned.

Routine sequencing of the haemagglutinin (HA) gene has revealed links with an H3 virus in a symptomatic traveller from Mexico, they reported to the online infectious diseases forum, Pro-MED, on May 6.

"We wonder to what extent the profile of influenza-like illness initially reported from mid-March 2009 in Mexico may in part be attributed to this H3N2 variant, in addition to the emergence of the novel A/H1N1 virus."

Although the reported amino acid substitutions fulfil standard criteria for "meaningful" antigenic drift, they may yet "signal important evolution in the HA gene", the BCCDC team warn.

The main implications of missing the involvement of H3N2, in addition to case screening and virus monitoring, relate to vaccine development: "The occurrence of progressive variation in the HA gene of H3N2-type seasonal influenza virus...may have consequences for the outcome of the next seasonal influenza vaccination programme."

The team go on to warn of the need to "remain vigilant for further H3N2 evolution and reduced vaccine relatedness", and call for the ongoing sequence analysis of H3 viruses from other countries.

As part of an ongoing investigation, Clinica last week revealed comments by Mexican health minister Jos? Angel C?rdova Villalobos regarding the health authorities' response to an outbreak of flu reported in Perote, Veracruz, on April 2. The outbreak triggered a local alert and, "in looking for the influenza virus, the majority of cases tested were H2N3", said Dr C?rdova during an April 27 press conference (see Clinica's April 30 report).

Pending confirmation and further details from the health ministry and the WHO, some experts have since questioned these findings, suggesting that the reference to H2N3 was most probably an error in the press conference transcript obtained by Clinica on April 28. It was suggested that H3N2 (a seasonal influenza virus), may have instead been reported, before the emergence of H1N1.

Other leading experts in the field have appeared more open-minded, suggesting that features of the Mexican/international situation do not, indeed, add up, and that a second virus could well explain the discrepancies.

[jeanne]

Re: H3N2 Strain Information

the idea of other circulating strains also having mutated into novel strains is being talked about here:

[jeanne]

Re: H3N2 Strain Information

http://www.curevents.com/vb/showthread.php?t=100884