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Source: http://www.promedmail.org/pls/otn/f?...3A1000%2C88804
Archive Number 20110609.1749
Published Date 09-JUN-2011
Subject PRO/EDR> Influenza (40): H3N2/H1N1 reassortant ex patient
INFLUENZA (40): H3N2/H1N1 REASSORTANT ex PATIENT
************************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: Wed 8 Jun 2011
From: Jonathan Gubbay <Jonathan.Gubbay@oahpp.ca> [edited]
Reassortment following coinfection with seasonal H3N2 and pandemic
(H1N1) 2009 viruses in Ontario, Canada
----------------------------------------------------------------------
A 16-month-old infant was admitted to a Greater Toronto Area Hospital
on 24 Jan 2011 with respiratory and gastrointestinal symptoms. After
15 hours, he was discharged home and subsequently recovered
uneventfully. 2 nasopharyngeal swabs were collected on the day of
admission and sent to the Ontario Agency for Health Protection (OAHPP)
Public Health Laboratories (PHL) for influenza testing by real-time
reverse transcriptase PCR (rRT-PCR). Influenza A [virus] was detected
in both specimens by rRT-PCR, and when subtyped were positive for
hemagglutinin (H3) gene in a moderately high copy number (cycle
thresholds 29 and 31). They were also noted to be positive for the
pandemic (H1N1) 2009 (pH1N1) neuraminidase (NA) gene at a very low
level (CT values 38 and 39), which was detected using an in-house
rRT-PCR (1). Suspecting contamination, primary samples were
reextracted and retested; identical results were obtained.
Further sequencing confirmed presence of the following genes in the
primary samples:
A. Pandemic H1N1 2009 genes: Matrix, NS, H1, N1
(H1 sequencing was conducted on one primary sample only)
B. Seasonal H3N2 genes: N2
(H3 sequencing was not conducted on either primary sample)
The 1st specimen underwent conventional viral culture in rhesus
monkey kidney cells. Whole genome sequence analysis of cultured
material showed that the isolate possessed H3 and N2 of seasonal H3N2
in combination with PB2, PB1, PA, NS, NP, and M of pandemic H1N1. Gene
sequences obtained in culture and primary specimen were identical. A
BLAST [basic local alignment search] was conducted against sequences
available in GenBank. The H3 and N2 gene sequences most closely
matched the currently circulating A/Perth/16/2009 strain.
The matrix and NS genes amplified from the primary sample were
identical to currently circulating pH1N1, most closely matching the
A/California/07/2009 strain.
Canada's National Microbiology Laboratory performed plaque forming
assays on the primary sample and culture material using Madin-Darby
canine kidney cell lines. Sequencing of individual plaque material in
both primary sample reconfirmed a reassortant virus as described
above, with no evidence of the HA and NA genes of pH1N1. In addition,
gene sequences obtained in both plaque assays matched each other, and
were also identical to those obtained at OAHPP. The isolate strain
type was A/Perth/16/09 (H3N2) by hemagglutination inhibition assay.
Summary and implications
------------------------
This case represents coinfection with H3N2 and pH1N1, followed by
reassortment in the patient (in vivo reassortment). The low level of
pandemic H1N1 2009 NA gene in the primary sample indicates that the
reassortment occurred in the child and the lab detected a remnant of
NA left behind. If it were just coinfection but not reassortment, we
would have expected to find evidence of H3N2 viral genes other than H3
and N2 in the primary sample. The subsequent reassortant virus
consisted of HA and NA of H3N2 together with the remaining 6 genes
(PB2, PB1, PA, NS, NP and M) of pH1N1.
To the best of our knowledge, this is the 1st case of reassortment
involving pH1N1 and seasonal H3N2. We could not document any
transmission of this reassortant, which arose during a coinfection
involving both subtypes. In a recent study reverse genetics was used
to generate a laboratory reassortant of this type -- infection of
ferrets with this reassortant resulted in higher levels of virus and
more severe respiratory damage when compared to wild-type pH1N1 (2).
This case and the 5 reports of human infection with swine triple
reassortant H3N2 in the United States since September 2010 highlight
the need for ongoing molecular and phenotypic surveillance for novel
influenza strains (3).
References
----------
1. Duncan C, Guthrie JL, Tijet N, et al: Analytical and clinical
validation of novel real-time reverse transcriptase-polymerase chain
reaction assays for the clinical detection of swine-origin H1N1
influenza viruses. Diagn Microbiol Infect Dis. 2011; 69(2): 167-71
[available at
<http://www.cnic.org.cn/pdf/2011-1-29/Analytical%20and%20clinical%20validation%20of%20no vel%20.pdf>].
2. Schrauwen EJ, Herfst S, Chutinimitkul S, et al: Possible increased
pathogenicity of pandemic (H1N1) 2009 influenza virus upon
reassortment. Emerg Infect Dis. 2011;17(2):200-8 [available at
<http://www.cdc.gov/eid/content/17/2/200.htm>].
3. Centers for Disease Control and Prevention (CDC). Update:
influenza activity -- United States, 2010-11 influenza season, and
composition of the 2011-12 influenza vaccine. MMWR-Morb Mortal Wkly
Rep. 2011; 60(21): 705-12 [available at
<http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6021a5.htm>].
Authors:
R Eshaghi 1, SN Patel 1,2, A Li 1, D Grewal 3, D Kobasa 4, N Bastien
4, Y Li 4, DE Low 1,2,5, and JB Gubbay 1,2,5
1. Public Health Laboratory, Ontario Agency for Health Protection and
Promotion (OAHPP), Canada.
2. University of Toronto, Toronto, Ontario, Canada.
3. Markham Stouffville Hospital, Markham, Ontario, Canada
4. Influenza and Respiratory Viruses Section, National Microbiology.
Laboratory, Public Health Agency of Canada.
5. Mount Sinai Hospital, Toronto, Ontario. Canada.
--
Jonathan Gubbay
Medical Microbiologist
Public Health Laboratory - Toronto
Ontario Agency for Health Protection and Promotion (OAHPP)
Toronto, Ontario, Canada
<jonathan.gubbay@oahpp.ca>
[ProMED-mail is indebted to Dr Gubbay and colleagues for drawing the
attention of readers to the outcome of an investigation which has
established that the coinfection of a child with pandemic H1N1 and
seasonal H3N2 influenza viruses in the Toronto area was accompanied by
genome reassortment in the patient ( _in vivo_ reassortment). A
recombinant (reassortant) virus was recovered from the patient
possessing the external protein genes of the H3N2 influenza virus and
the internal protein genes of the pandemic H1N1 influenza virus.
During the 2010/2011 influenza epidemic season in North America both
the seasonal H3N2 and the pandemic H1N1 viruses have been prevalent
and the occurrence of coinfection is not surprising, but this appears
to be the 1st demonstration of _in vivo_ reassortment. Fortunately the
infected child has recovered and the recombinant (reassortant) virus
was not transmitted. It remains to be seen whether this or similar
reassortants will appear in subsequent epidemics. - Mod.CP]
[see also:
2010
----
Influenza pandemic (H1N1) (42): reassortment, swine 20100618.2055
Influenza pandemic (H1N1) (22): Canada (SK), reassortment
20100305.0734
Influenza pandemic (H1N1) (19): reassortment 20100302.0689]
.................................................c p/mj/dk
*################################################# #########*
************************************************** **********
ProMED-mail makes every effort to verify the reports that
are posted, but the accuracy and completeness of the
information, and of any statements or opinions based
thereon, are not guaranteed. The reader assumes all risks in
using information posted or archived by ProMED-mail. ISID
and its associated service providers shall not be held
responsible for errors or omissions or held liable for any
damages incurred as a result of use or reliance upon posted
or archived material.
************************************************** **********
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Archive Number 20110609.1749
Published Date 09-JUN-2011
Subject PRO/EDR> Influenza (40): H3N2/H1N1 reassortant ex patient
INFLUENZA (40): H3N2/H1N1 REASSORTANT ex PATIENT
************************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: Wed 8 Jun 2011
From: Jonathan Gubbay <Jonathan.Gubbay@oahpp.ca> [edited]
Reassortment following coinfection with seasonal H3N2 and pandemic
(H1N1) 2009 viruses in Ontario, Canada
----------------------------------------------------------------------
A 16-month-old infant was admitted to a Greater Toronto Area Hospital
on 24 Jan 2011 with respiratory and gastrointestinal symptoms. After
15 hours, he was discharged home and subsequently recovered
uneventfully. 2 nasopharyngeal swabs were collected on the day of
admission and sent to the Ontario Agency for Health Protection (OAHPP)
Public Health Laboratories (PHL) for influenza testing by real-time
reverse transcriptase PCR (rRT-PCR). Influenza A [virus] was detected
in both specimens by rRT-PCR, and when subtyped were positive for
hemagglutinin (H3) gene in a moderately high copy number (cycle
thresholds 29 and 31). They were also noted to be positive for the
pandemic (H1N1) 2009 (pH1N1) neuraminidase (NA) gene at a very low
level (CT values 38 and 39), which was detected using an in-house
rRT-PCR (1). Suspecting contamination, primary samples were
reextracted and retested; identical results were obtained.
Further sequencing confirmed presence of the following genes in the
primary samples:
A. Pandemic H1N1 2009 genes: Matrix, NS, H1, N1
(H1 sequencing was conducted on one primary sample only)
B. Seasonal H3N2 genes: N2
(H3 sequencing was not conducted on either primary sample)
The 1st specimen underwent conventional viral culture in rhesus
monkey kidney cells. Whole genome sequence analysis of cultured
material showed that the isolate possessed H3 and N2 of seasonal H3N2
in combination with PB2, PB1, PA, NS, NP, and M of pandemic H1N1. Gene
sequences obtained in culture and primary specimen were identical. A
BLAST [basic local alignment search] was conducted against sequences
available in GenBank. The H3 and N2 gene sequences most closely
matched the currently circulating A/Perth/16/2009 strain.
The matrix and NS genes amplified from the primary sample were
identical to currently circulating pH1N1, most closely matching the
A/California/07/2009 strain.
Canada's National Microbiology Laboratory performed plaque forming
assays on the primary sample and culture material using Madin-Darby
canine kidney cell lines. Sequencing of individual plaque material in
both primary sample reconfirmed a reassortant virus as described
above, with no evidence of the HA and NA genes of pH1N1. In addition,
gene sequences obtained in both plaque assays matched each other, and
were also identical to those obtained at OAHPP. The isolate strain
type was A/Perth/16/09 (H3N2) by hemagglutination inhibition assay.
Summary and implications
------------------------
This case represents coinfection with H3N2 and pH1N1, followed by
reassortment in the patient (in vivo reassortment). The low level of
pandemic H1N1 2009 NA gene in the primary sample indicates that the
reassortment occurred in the child and the lab detected a remnant of
NA left behind. If it were just coinfection but not reassortment, we
would have expected to find evidence of H3N2 viral genes other than H3
and N2 in the primary sample. The subsequent reassortant virus
consisted of HA and NA of H3N2 together with the remaining 6 genes
(PB2, PB1, PA, NS, NP and M) of pH1N1.
To the best of our knowledge, this is the 1st case of reassortment
involving pH1N1 and seasonal H3N2. We could not document any
transmission of this reassortant, which arose during a coinfection
involving both subtypes. In a recent study reverse genetics was used
to generate a laboratory reassortant of this type -- infection of
ferrets with this reassortant resulted in higher levels of virus and
more severe respiratory damage when compared to wild-type pH1N1 (2).
This case and the 5 reports of human infection with swine triple
reassortant H3N2 in the United States since September 2010 highlight
the need for ongoing molecular and phenotypic surveillance for novel
influenza strains (3).
References
----------
1. Duncan C, Guthrie JL, Tijet N, et al: Analytical and clinical
validation of novel real-time reverse transcriptase-polymerase chain
reaction assays for the clinical detection of swine-origin H1N1
influenza viruses. Diagn Microbiol Infect Dis. 2011; 69(2): 167-71
[available at
<http://www.cnic.org.cn/pdf/2011-1-29/Analytical%20and%20clinical%20validation%20of%20no vel%20.pdf>].
2. Schrauwen EJ, Herfst S, Chutinimitkul S, et al: Possible increased
pathogenicity of pandemic (H1N1) 2009 influenza virus upon
reassortment. Emerg Infect Dis. 2011;17(2):200-8 [available at
<http://www.cdc.gov/eid/content/17/2/200.htm>].
3. Centers for Disease Control and Prevention (CDC). Update:
influenza activity -- United States, 2010-11 influenza season, and
composition of the 2011-12 influenza vaccine. MMWR-Morb Mortal Wkly
Rep. 2011; 60(21): 705-12 [available at
<http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6021a5.htm>].
Authors:
R Eshaghi 1, SN Patel 1,2, A Li 1, D Grewal 3, D Kobasa 4, N Bastien
4, Y Li 4, DE Low 1,2,5, and JB Gubbay 1,2,5
1. Public Health Laboratory, Ontario Agency for Health Protection and
Promotion (OAHPP), Canada.
2. University of Toronto, Toronto, Ontario, Canada.
3. Markham Stouffville Hospital, Markham, Ontario, Canada
4. Influenza and Respiratory Viruses Section, National Microbiology.
Laboratory, Public Health Agency of Canada.
5. Mount Sinai Hospital, Toronto, Ontario. Canada.
--
Jonathan Gubbay
Medical Microbiologist
Public Health Laboratory - Toronto
Ontario Agency for Health Protection and Promotion (OAHPP)
Toronto, Ontario, Canada
<jonathan.gubbay@oahpp.ca>
[ProMED-mail is indebted to Dr Gubbay and colleagues for drawing the
attention of readers to the outcome of an investigation which has
established that the coinfection of a child with pandemic H1N1 and
seasonal H3N2 influenza viruses in the Toronto area was accompanied by
genome reassortment in the patient ( _in vivo_ reassortment). A
recombinant (reassortant) virus was recovered from the patient
possessing the external protein genes of the H3N2 influenza virus and
the internal protein genes of the pandemic H1N1 influenza virus.
During the 2010/2011 influenza epidemic season in North America both
the seasonal H3N2 and the pandemic H1N1 viruses have been prevalent
and the occurrence of coinfection is not surprising, but this appears
to be the 1st demonstration of _in vivo_ reassortment. Fortunately the
infected child has recovered and the recombinant (reassortant) virus
was not transmitted. It remains to be seen whether this or similar
reassortants will appear in subsequent epidemics. - Mod.CP]
[see also:
2010
----
Influenza pandemic (H1N1) (42): reassortment, swine 20100618.2055
Influenza pandemic (H1N1) (22): Canada (SK), reassortment
20100305.0734
Influenza pandemic (H1N1) (19): reassortment 20100302.0689]
.................................................c p/mj/dk
*################################################# #########*
************************************************** **********
ProMED-mail makes every effort to verify the reports that
are posted, but the accuracy and completeness of the
information, and of any statements or opinions based
thereon, are not guaranteed. The reader assumes all risks in
using information posted or archived by ProMED-mail. ISID
and its associated service providers shall not be held
responsible for errors or omissions or held liable for any
damages incurred as a result of use or reliance upon posted
or archived material.
************************************************** **********
Donate to ProMED-mail. Details available at:
<http://www.isid.org/ProMEDMail_Donations.shtml>
************************************************** **********
Visit ProMED-mail's web site at <http://www.promedmail.org>.
Send all items for posting to: promed@promedmail.org (NOT to
an individual moderator). If you do not give your full name
name and affiliation, it may not be posted. You may unsub-
scribe at <http://www.isid.org/promedmail/subscribe.lasso>.
For assistance from a human being, send mail to:
<postmaster@promedmail.org>.
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