Rhiza Labs FluTracker Forum

An early release MMWR will be issued today by the CDC. I knew that the trH3N2 from West Viginia (epidemiologoccally linked to A/West Virginia/06/2011) would be released today. The CDC just released full sequences from a novel trH1N1, A/Wisconsin/28/2011 with H1N1pdm09 PA and M genes and an H3N2pdm11 NP gene (swine H1 and N1).

I had asked earlier this week how many human triple reassortants would be named this week, and received no reply.

There will be at least two triple reassortants today.

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Looks like the early release MMWR will be late (as in Friday afternoon dump, which is reserved for BAD news)

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It's starting to look like a mighnight special.

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Two human infections with novel influenza A viruses were detected in two states (West Virginia and Wisconsin). One patient was infected with an influenza A (H1N1) variant virus with genes from human, swine, and avian lineages (A(H1N1)v) and reported close contact with pigs prior to illness onset. The other patient was infected with an influenza A (H3N2) variant virus with genes from human, swine, and avian lineages (A(H3N2)v) and did not have contact with pigs prior to illness onset, but did have contact with another confirmed case of A(H3N2)v. Both patients have recovered from their illnesses. Additional information on the Wisconsin case can be found in the CDC Have You Heard posting and additional information on the West Virginia case can found in the related MMWR article.

CDC is required to report all cases of human infection with novel influenza viruses to the World Health Organization (WHO) as part of the International Health Regulations (IHR). Domestically, CDC reports these cases in this report and on its website. Early identification and investigation of human infections with novel influenza A viruses is critical to evaluate the extent of the outbreak and possible human-to-human transmission. Additional information on human infections with novel influenza viruses can be found at Information on Variant Influenza A Viruses.

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http://www.cdc.gov/mmwr/preview/mmwrhtm ... 0e1223a1_w

Update: Influenza A (H3N2)v Transmission and Guidelines — Five States, 2011
Early Release
December 23, 2011 / 60(Early Release);1-4


From August 17 to December 23, 2011, CDC received reports of 12 human infections with influenza A (H3N2)v viruses that have the matrix (M) gene from the influenza A (H1N1)pdm09 virus (formerly called swine-origin influenza A [H3N2] and pandemic influenza A [H1N1] 2009 viruses, respectively [Box]). The 12 cases occurred in five states (Indiana, Iowa, Maine, Pennsylvania, and West Virginia), and 11 were in children (1,2). Six of the 12 patients had no identified recent exposure to swine. Three of the 12 patients were hospitalized, and all have recovered fully.

A case in an adult male in Indiana with occupational exposure to swine was among the 12, and two children in West Virginia who regularly attended the same day care accounted for the latest cases. This report describes those cases and swine influenza virus (SIV) surveillance being conducted by the U.S. Department of Agriculture (USDA).

Case Reports
Indiana. On October 28, 2011, CDC was notified by the Indiana Department of Health of a suspected case of A(H3N2)v virus infection in an adult male. The patient experienced onset of fever, cough, shortness of breath, nausea, vomiting, and body aches on October 20, and was hospitalized for 4 days. He did not receive treatment with influenza antiviral medications and recovered fully.

On October 22, a respiratory specimen from the patient was positive for influenza at the hospital. On October 28, the virus was identified by real-time, reverse transcription–polymerase chain reaction (rRT-PCR) testing at the Indiana State Public Health Laboratory as an inconclusive influenza A virus, consistent with results seen with other recent A(H3N2)v infections. On October 31, genome sequencing at CDC confirmed the virus as A(H3N2)v with the M gene from the A(H1N1)pdm09 virus, similar to the viruses identified in the other cases of human infection in the United States since August 2011.

The patient reported direct contact with swine during his work in the week before illness onset. He said he did not wear any personal protective equipment (PPE) because the swine did not exhibit signs of illness. No illness was reported among the patient's household members or other close contacts.

West Virginia. On November 19, a child aged <5 years developed acute onset of fever after 1 week of cough and congestion. The child had been hospitalized for an unrelated condition 2 days before the onset of fever. On November 21, a respiratory specimen was collected. Rapid diagnostic tests conducted by the hospital were negative for influenza and respiratory syncytial virus, but influenza A was identified by an alternative rRT-PCR at the hospital. The specimen was forwarded to the West Virginia Office of Laboratory Services, where it was identified as a suspected influenza A (H3N2)v virus. Subsequent genome sequencing conducted at CDC confirmed the virus as A(H3N2)v with the M gene from the A(H1N1)pdm09 virus. The child, who had no recent travel or exposure to swine, was discharged on November 21, and has since recovered from the influenza illness.

An investigation was conducted to ascertain respiratory illnesses among contacts of the child that occurred during November 9–December 19. Multiple contacts, including children who regularly attended day care with the child, were found to have had respiratory illness during this period. On November 29, a second child aged <5 years who attended day care regularly with the first child and who had no recent travel or swine exposure became ill with fever, cough, diarrhea, and rhinorrhea. The second child did not seek medical care and recovered fully from the illness. A respiratory specimen obtained from the second child on December 7 was inconclusive by rRT-PCR at the West Virginia Office of Laboratory Services; however, the specimen was confirmed as influenza A (H3N2)v with the M gene from the A(H1N1)pdm09 virus via genome sequencing at CDC.

No additional A(H3N2)v cases have been identified among the other ill day care attendees or contacts of either patient. Enhanced surveillance for influenza-like illness and increased diagnostic testing of respiratory specimens is being conducted in West Virginia and adjacent counties in Maryland as part of the ongoing investigation of these cases. Currently, no evidence of additional human-to-human transmission in the community has been identified.

Influenza Surveillance of U.S. Swine
Surveillance for SIV in the United States is overseen by USDA, largely in swine that display influenza-like illness. In July 2009, USDA's Animal and Plant Health Inspection Service and the swine industry implemented a SIV surveillance program* to characterize the distribution of SIV in U.S. swine herds. To date, approximately 150 SIV isolates have undergone sequencing of three genes (hemagglutinin, matrix, and neuraminidase gene segments) and sequences have been submitted to GenBank.† Thirty isolates have been identified as A(H3N2) viruses and eight of those 30 have the M gene from the influenza A (H1N1)pdm09 virus as determined by an informal analysis of GenBank submission data by the USDA Agricultural Research Service. Further characterization and analysis are ongoing, and new submissions are added as diagnostic work is completed.

Reported by
Shawn Richards, Mark Glazier, Katie Masterson, Michael Denton, Indiana State Dept of Health; Cheryl Miller, DVM, Indiana Board of Animal Health. Carl Liebig, MD, Andrew J. Root, Cynthia Whitt, Mineral County Health Dept, Julie Freshwater, PhD, Sherif Ibrahim, MD, Danae Bixler, MD, Christi Clark, Loretta Haddy, PhD, West Virginia Dept of Public Health. Swine Influenza Virus Team, U.S. Dept of Agriculture. Douglas Jordan, MA, Matthew Biggerstaff, MPH, Scott Epperson, MPH, Lynnette Brammer, MPH, Lyn Finelli, DrPH, Susan Trock, DVM, Michael Jhung, MD, Joseph Bresee, MD, Stephen Lindstrom, PhD, Alexander Klimov, PhD, Daniel Jernigan, MD, Nancy Cox, PhD, Influenza Div, National Center for Immunization and Respiratory Diseases. Rachel Radcliffe, DVM, Career Epidemiology Field Officer Program, Office of Public Health Preparedness and Response; Tegwin Taylor, DVM, EIS officer, CDC. Corresponding contributor: Douglas Jordan, dejordan@cdc.gov, 404-639-3747.

Editorial Note
Human infections with the influenza viruses currently circulating among swine are rare. Since 2005, only 35 cases have been reported in the United States, but the frequency with which they have been detected increased in 2011. When different influenza viruses simultaneously infect a single host (e.g., a human or swine), exchange of genetic material can occur, resulting in a new influenza virus. Depending on the antigenic distance between the new virus and recently circulating seasonal viruses, little or no immunity might exist in the human population. Influenza A (H3N2)v viruses resulted from reassortment of influenza A (H1N1)pdm09 viruses with swine influenza A (H3N2) viruses. A diagram depicting this reassortment is available online from CDC's Public Health Image Library.§ Because these viruses carry a newly identified combination of genes, little information is available regarding transmission efficiency in swine, in humans, or between swine and humans. However, the recent human cases involving swine exposure and results of SIV surveillance indicate that these viruses also currently are circulating in swine herds.

The case of influenza A (H3N2)v infection after occupational contact with swine in Indiana and the apparent limited human-to-human transmission of A(H3N2)v virus that occurred in a day care setting in West Virginia represent two different possible scenarios for transmission of this virus. Work exposure highlights the risk for interspecies influenza transmission in occupational settings where humans are exposed to swine, an association that has been described previously (3–7). To minimize the risk for interspecies influenza transmission in occupational settings, CDC and the Occupational Safety and Health Administration (OSHA) encourage swine workers to 1) get vaccinated against human seasonal influenza, 2) wear appropriate PPE, and 3) practice good hygiene, such as washing hands thoroughly with soap and water, when in contact with swine, especially swine that show signs of illness. The National Pork Board also recommends producers work with their veterinarian to develop appropriate prevention and control measures for influenza in swine, which can include vaccinating swine against swine influenza. Similar to humans, swine infected with influenza viruses do not always exhibit signs of infection (8). Persons with swine exposure in the week before onset of an illness with symptoms of influenza requiring medical care should notify their health-care provider of their swine exposures. Persons who develop symptoms of influenza after close contact with swine are recommended to stay home until well to minimize contact with persons and swine as much as possible.

Guidance materials for persons who work with swine have been published by OSHA.¶ In addition, the National Pork Board,** CDC, and the National Association of State Public Health Veterinarians have published guidance for persons exposed to swine in public settings (9). Clinicians should consider variant influenza virus infection in the differential diagnosis of patients with febrile respiratory illness who have been near swine whether at work or at an agricultural event, such as a fair or exhibit.

The A(H3N2)v cases in West Virginia involved two children who attended the same day care, but the first child was unlikely to have transmitted the virus to the second child, given the ≥10-day difference in their symptom onset dates. This represents a scenario of limited human-to-human transmission occurring in a day care setting. Therefore, clinicians also should consider the possibility of influenza A (H3N2)v infections in patients who have not had exposure to swine, particularly young children in those states where influenza A (H3N2)v cases have been reported. Clinicians who suspect variant influenza virus infection should obtain a nasopharyngeal swab, place the swab in viral transport medium, and contact their state or local health department to facilitate transport and timely diagnosis (10). Influenza A (H3N2)v viruses detected to date are susceptible to oseltamivir and zanamivir for the treatment of influenza. Clinicians who suspect variant influenza infection in a patient should consider treatment with these medications if clinically indicated (10). Because these viruses have the M gene from the influenza A (H1N1)pdm09 virus, they are resistant to amantadine and rimantadine. CDC requests that state public health laboratories notify CDC immediately of suspected variant influenza A specimens and send them to the CDC Influenza Division's Virus Surveillance and Diagnostics Branch Laboratory. Confirmed cases should be investigated thoroughly and expeditiously to ascertain whether swine-to-human or human-to-human transmission is ongoing and to limit further exposures between humans with others and swine. Such investigations require close collaboration among state, local, and federal public and animal health officials.

CDC is working with USDA and state public health and animal health experts in the locations where these cases have occurred to investigate each case fully and to enhance influenza surveillance to detect human cases of variant influenza virus infections. The CDC rRT-PCR assay that was approved by the Food and Drug Administration in September 2011 is able to identify these cases as presumptive influenza A (H3N2)v cases. These diagnostic test kits have been distributed to public health laboratories in the United States and National Influenza Centers designated by the World Health Organization in other countries. Additional rRT-PCR test enhancements to further improve detection of influenza A (H3N2)v viruses are under development.

Limited serologic studies conducted to date indicate that young children have little preexisting immunity to influenza A (H3N2)v viruses. Because the hemagglutinin genes of these viruses are related to human influenza A (H3N2) viruses that circulated in the 1990s, older children and adults might have limited immunity against these viruses. Certain persons, including young children, pregnant women, persons with chronic health conditions such as asthma, diabetes, or heart and lung disease, and persons aged ≥65 years, are likely to be at greater risk for serious influenza-related complications from variant influenza viruses such as influenza A (H3N2)v. The influenza A (H3N2)v virus is different enough from current human seasonal influenza viruses that the seasonal influenza vaccine is not expected to provide significant protection.

CDC will provide routine and timely communications regarding these influenza A (H3N2)v viruses and other variant influenza viruses with the public, partners, state and local health departments, and stakeholders. Updated information and guidance documents related to A(H3N2)v viruses are available online from CDC at http://www.cdc.gov/flu/swineflu/influen ... iruses.htm.

References
CDC. Swine-origin influenza A (H3N2) virus infection in two children—Indiana and Pennsylvania, July–August 2011. MMWR 2011;60:1213–5.
CDC. Limited human-to-human transmission of novel influenza A (H3N2) virus—Iowa, November 2011. MMWR 2011;60:1615–7.
Myers KP, Olsen CW, Gray GC. Cases of swine influenza in humans: a review of the literature. Clin Infect Dis 2007;44:1084–8.
Wells DL, Hopfensperger DJ, Arden NH, et al. Swine influenza virus infections. Transmission from ill pigs to humans at a Wisconsin agricultural fair and subsequent probable person-to-person transmission. JAMA 1991;265:478–81.
Olsen CW, Brammer L, Easterday BC, et al. Serologic evidence of H1 swine influenza virus infection in swine farm residents and employees. Emerg Infect Dis 2002;8:814–9.
Forgie SE, Keenliside J, Wilkinson C, et al. Swine outbreak of pandemic influenza A virus on a Canadian research farm supports human-to-swine transmission. Clin Infec Dis 2011;52:10–8.
Ramirez A, Capuano AW, Wellman DA, et al. Preventing zoonotic influenza virus infection. Emerg Infec Dis 2006;12:997–1000.
Terebuh P, Olsen CW, Wright J, et al. Transmission of influenza A viruses between pigs and people, Iowa, 2002–2004. Influenza Other Respi Viruses 2010;4:387–96.
CDC, National Association of State Public Health Veterinarians, Inc. Compendium of measures to prevent disease associated with animals in public settings, 2011. MMWR 2011;60(No. RR-4).
CDC. Antiviral agents for the treatment and chemoprophylaxis of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 2011;60(No. RR-1).


* Additional information is available at http://www.aphis.usda.gov/animal_health ... nual.shtml.

† Available at http://www.ncbi.nlm.nih.gov/genbank.

§ Available at http://phil.cdc.gov/phil/details.asp (image ID: 13469).

¶ Available at http://www.osha.gov/publications/influe ... tsheet.pdf .

** Additional information is available at http://pork.org/filelibrary/factsheets/ ... a04726.pdf .



What is already known on this topic?

During August–December 2011, a total of 12 human infections with influenza A (H3N2)v viruses were identified in the United States (two from Indiana, three from Iowa, two from Maine, three from Pennsylvania, and two from West Virginia).

What is added by this report?

This report provides the new nomenclature for the virus and describes three cases, one in an adult with occupational exposure and two in children involving limited human-to-human transmission in a day care setting. It also provides an overview of the U.S. Department of Agriculture's swine influenza virus (SIV) surveillance program along with data on influenza A (H3N2) viruses in swine. Out of approximately 150 SIV isolates that have undergone sequencing of three genes (hemagglutinin, matrix, and neuraminidase gene segments), 30 have been identified as A(H3N2) viruses; eight of those 30 have the M gene from the influenza A (H1N1)pdm09 virus.

What are the implications for public health practice?

Nonhuman influenza virus infections rarely result in human-to-human transmission, but the implications of sustained ongoing transmission between humans is potentially severe; therefore, prompt and thorough identification and investigation of sporadic human infections with novel influenza viruses are needed to reduce the risk for sustained transmission.



BOX. Changes in nomenclature for the swine-origin influenza A (H3N2) and pandemic influenza A (H1N1) 2009 viruses

After discussions among the World Health Organization (WHO), the World Organization for Animal Health, the Food and Agriculture Organization, CDC, and other U.S. federal agencies, swine-origin influenza viruses identified in humans will now be referred to as "variant" viruses and denoted with a "v." Influenza viruses identified in swine populations will continue to be referred to as "swine influenza" viruses.

This change in nomenclature follows announcement by WHO of a decision to standardize nomenclature for the pandemic influenza A (H1N1) 2009 virus (which has had diverse names) as influenza A (H1N1)pdm09 (1).

Since August 2011, CDC has identified 12 human infections in five states with swine-origin influenza A (H3N2) viruses. Per the new naming convention, these H3N2 viruses will now be referred to as "influenza A (H3N2) variant viruses with genes from avian, swine and human viruses," and will be abbreviated as "A(H3N2)v" for scientific use and "H3N2v" for general public use. These 12 A(H3N2)v viruses also have the M gene from the A(H1N1)pdm09 virus.

Reference
1. World Health Organization. Standardization of terminology of the pandemic A(H1N1) 2009 virus. Wkly Epidemiol Rec 2011;86:480.

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CDC acknowledges that cluster is significantly larger than the two confirmed cases.

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CDC Confirms Detection of A Different Influenza A Variant Virus


December 23, 2011 -- An influenza A (H1N1) virus that is known to circulate in U.S. swine but not humans has been detected in an adult in the state of Wisconsin. The patient reported occupational contact with swine prior to illness onset. No human-to-human transmission with this virus has been identified. CDC laboratory testing has confirmed that this is a new reassortant influenza A H1N1 virus as it has acquired the matrix [M] gene from the 2009 H1N1 pandemic virus. Laboratory testing shows that the virus is susceptible to the influenza antiviral medications, oseltamivir and zanamivir. Surveillance for additional human cases in the area has been enhanced. Providers are being asked to collect specimens for influenza virus testing from any patient presenting with influenza-like illness.

The virus identified in Wisconsin has genes from avian, swine and human influenza viruses, making it a so-called “triple reassortant” (tr) virus. Triple reassortant viruses have been circulating in U.S. swine since the 1990s. However the virus detected in Wisconsin is different from earlier triple reassortant influenza A H1N1 viruses in swine (tr-H1N1) in that it has acquired the matrix [M] gene) from the 2009 influenza A (H1N1) virus. A review of publicly posted influenza genome sequence web sites indicates this reassortment (the tr-H1N1 virus common in swine with the 2009 H1N1 M gene) has been found in U.S. swine since 2010. However, this is the first time this genetic sequence has been detected in a human. Gene sequences of the virus detected in Wisconsin have been posted to publicly available web sites.

A recently adopted naming convention for viruses that commonly circulate in swine uses a “v” (for “variant”) when these viruses infect humans, regardless of whether the virus contains the 2009 H1N1 M gene. Following this convention, the Wisconsin virus will be called H1N1v.
This genetic change (acquisition of the 2009 H1N1 virus matrix [M] gene) has been seen in triple reassortant H3N2 viruses that have infected 12 people since August 2011. (These cases occurred in West Virginia (2), Indiana (2), Pennsylvania (3), Maine (2), and Iowa (3).) These variant H3N2 viruses are being called “H3N2v.”

The 2009 H1N1 virus was likely transmitted to swine from humans during and after the 2009-2010 pandemic and now is commonly spreading in both humans and in swine. Given that, and the ability of influenza viruses to change, it is not surprising to see influenza viruses that normally circulate in swine acquire gene segments from the 2009 H1N1 virus. In fact, monitoring of influenza viruses circulating in swine has indicated that the 2009 influenza A (H1N1) virus has reassorted (swapped genes) with other swine influenza A viruses as well.

The M gene plays a role in influenza virus infection, assembly and replication, but the significance of the acquisition of the 2009 H1N1 M gene in influenza viruses that normally circulate in swine is unknown at this time. CDC is continuing to investigate the implications of this genetic change; however, limited data from one animal model (in guinea pigs) indicate that acquisition of this M gene may make influenza viruses more readily transmissible among guinea pigs. Whether the same would be true among swine or humans is not known.

Although the majority of human infections with animal influenza viruses do not result in human-to-human transmission, each case should be investigated fully to determine if these viruses are transmitted among humans and to limit further exposure of humans to infected animals, if infected animals are suspected. Such investigations require close collaboration among state, local, and federal public and animal health officials. While human-to-human transmission of the virus in Wisconsin has not been detected, human-to-human transmission of H3N2v has been reported, previously in Iowa and most recently in West Virginia.

CDC recommends an annual seasonal flu vaccine to protect against seasonal influenza viruses; however, a seasonal flu vaccine is unlikely to protect people against variant flu viruses that are very different from circulating human viruses. Two FDA–cleared drugs – oseltamivir and zanamivir - are expected to be effective in treating illness associated with H1N1v, as well as H3N2v viruses. (For more information about influenza antiviral medications, please see www.cdc.gov/flu/antivirals/whatyoushould.htm ).

CDC is recommending that clinicians who suspect influenza virus infection in humans with recent exposure to swine obtain a nasopharyngeal swab from the patient for timely diagnosis at a state public health laboratory and consider empiric neuraminidase inhibitor antiviral treatment.
At this time, CDC recommends the following:

People who experience flu symptoms following direct or close contact with swine and who require medical attention (see below) should mention this exposure to their doctor or health care provider. (A list of flu symptoms is available at www.cdc.gov/flu/about/disease/symptoms.htm.)
For people who have NOT had exposure to swine and develop ILI, CDC’s recommendations for seeking treatment are the same as they are for seasonal influenza.
If you have symptoms of flu and are very sick or worried about your illness contact your health care provider.
Certain people are at greater risk of serious flu-related complications (including young children, elderly persons, pregnant women and people with certain long-term medical conditions) and this is true both for seasonal flu and variant flu virus infections. (For a full list of people at higher risk of flu-related complications, see www.cdc.gov/flu/about/disease/high_risk.htm.)
If these people develop ILI, it’s best for them to contact their doctor. (The majority of recent variant influenza A cases have been in children.)
Your doctor may prescribe antiviral drugs that can treat the flu. These drugs work better for treatment the sooner they are started.
Influenza has not been shown to be transmissible to people through eating properly handled and prepared pork (pig meat) or other products derived from pigs. For more information about the proper handling and preparation of pork, visit the USDA website fact sheet “Fresh Pork From Farm to Table.”

More information about swine influenza and links to all previous reports related to cases of variant influenza A infections are available on the CDC swine influenza website at www.cdc.gov/flu/swineflu/index.htm.

http://www.cdc.gov/media/haveyouheard/s ... riant.html

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Only one of the eight (from New York) matches the first 10 human cases. These seqeunces have been at Genbank since Nov 1.

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The US Centers for Disease Control and Prevention (CDC) today confirmed two more novel flu infections, one an H3N2 variant that has been identified in 11 other patients this year and one an H1N1 variant that has never been reported in humans before.

The CDC described the latest novel H3N2 case in an early-release article in Morbidity and Mortality Weekly Report (MMWR). The case, in a West Virginia child, involves a swine-origin H3N2 reassortant strain that includes the M gene from the 2009 H1N1 pandemic virus.

The CDC detailed the detection of the novel H1N1 virus in a "Have You Heard?" statement. The virus, also a triple-reassortant that has acquired the M gene of the 2009 H1N1 virus, sickened an adult in Wisconsin who had occupational contact with swine and has recovered.

The West Virginia child is a daycare contact of another child from West Virginia whose novel H3N2 infection was reported on Dec 9, the CDC said. The latest case turned up during an investigation to find out if any other children in the daycare were sick with the same virus. The second child, who is younger than age 5, got sick on Nov 29 with symptoms that included fever, cough, diarrhea, and rhinorrhea.

Like the first case-patient, the second child had no history of recent travel or swine exposure. The child did not seek medical care and has recovered fully, the CDC said.

A respiratory specimen obtained from the child on Dec 7 underwent rRT-PCR testing at the West Virginia Office of Laboratory Services, but the results were inconclusive. Genome sequencing at the CDC confirmed the virus as a novel H3N2 strain containing the M gene from the 2009 H1N1 virus.

The CDC said no other cases have been detected at the daycare or among the two children's contacts. West Virginia health officials and adjacent counties in Maryland are increasing their surveillance for flu-like illnesses, it added.

Though the two infections in West Virginia occurred in children who attended the same daycare, the CDC said the first child probably didn't transmit the virus to the second child, because their symptom onset dates were more than 10 days apart. However, it said the situation suggests limited human-to-human transmission in a daycare setting.

In late November, Iowa health officials reported two infections with the same H3N2 variant in two children who attended the same daycare.

The daycare setting is one of two scenarios that have been involved in the recent novel H3N2 cases, the CDC said. Though 11 of the 12 cases have occurred in children, one of the sick patients was an adult who had occupational exposure to swine.

The CDC said surveillance suggests the novel H3N2 virus is also circulating in swine herds. Of 150 swine influenza viruses that have been sequenced so far, 30 were H3N2 viruses, including 8 that had the M gene from the 2009 H1N1 virus. Further analysis is ongoing and new submissions to GenBank are being added as diagnostic work is completed, the agency said.

Regarding the novel H1N1 virus, the CDC said triple-reassortant viruses—ones that contain genes from avian, swine, and human flu viruses—have been circulating in US swine since the 1990s, and a review of genome sequencing databases suggests the variant that contains the M gene from the 2009 H1N1 virus has been found in US swine since 2010. But this case marks the first detection of such a strain in humans.

Testing shows that the virus is susceptible to the antiviral drugs oseltamivir (Tamiflu) and zanamivir (Relenza), the CDC said.

Given that the 2009 H1N1 virus is commonly circulating in swine and humans, the agency said, it isn't surprising to see viruses that typically transmit among pigs acquire gene segments from the 2009 H1N1 virus. CDC researchers are investigating the implications of the M gene in viruses that normally circulate in swine. So far, experiments suggest it makes flu more transmissible in guinea pigs, but it's not known if the same is true for pigs and humans.

In another development today, a working group from three health groups including the World Health Organization (WHO) recommended standardizing the terminology for the variant influenza viruses to help avoid confusion when referring to seasonal and other flu strains. For the novel H3N2 virus circulating in the United States, the group recommended using influenza A (H3N2)v, with the "v" standing for "variant."

The nomenclature working group also included members from the World Organization for Animal Health (OIE) and the United Nations Food and Agriculture Organization (FAO). The group said the novel H3N2 virus reported in the United States has not been detected anywhere else in the world.

The CDC said that, in line with the naming convention, it is calling the novel H1N1 virus H1N1v and the novel H3N2 virus H3N2v.

In seasonal flu news, the CDC said today that flu activity in the US was still at low levels last week. Doctor's visits for flu-like illness were still below baseline in all regions of the country, and the percentage of respiratory specimens testing positive for flu increased slightly from 1.9% to 2.1%, according to the weekly CDC surveillance report.

Deaths from pneumonia and flu dropped by a small amount and are at a level expected for this time of year, the CDC said, adding that no pediatric flu deaths were reported.

Meanwhile, the flu season in Europe doesn't appear to have started yet, with no sign of sustained transmission in any European Union countries so far, according to an update yesterday from the European Centre for Disease Prevention and Control (ECDC). It said all countries are reporting low flu activity, with 3.6% of respiratory specimens testing positive for flu. Most (88%) of the viruses that have been subtyped so far are seasonal H3N2, the ECDC said.

See also:

Dec 23 CDC weekly flu update

Dec 23 MMWR report

Dec 23 CDC "Have You Heard?" statement

Dec 23 joint statement on nomenclature

Dec 22 ECDC influenza update

http://www.cidrap.umn.edu/cidrap/conten ... lu-br.html

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http://www.cidrap.umn.edu/cidrap/conten ... lu-br.html

CDC reports two more novel flu infections
Lisa Schnirring Staff Writer


Dec 23, 2011 (CIDRAP News) – The US Centers for Disease Control and Prevention (CDC) today confirmed two more novel flu infections, one an H3N2 variant that has been identified in 11 other patients this year and one an H1N1 variant that has never been reported in humans before.

The CDC described the latest novel H3N2 case in an early-release article in Morbidity and Mortality Weekly Report (MMWR). The case, in a West Virginia child, involves a swine-origin H3N2 reassortant strain that includes the M gene from the 2009 H1N1 pandemic virus.

The CDC detailed the detection of the novel H1N1 virus in a "Have You Heard?" statement. The virus, also a triple-reassortant that has acquired the M gene of the 2009 H1N1 virus, sickened an adult in Wisconsin who had occupational contact with swine and has recovered.

The West Virginia child is a daycare contact of another child from West Virginia whose novel H3N2 infection was reported on Dec 9, the CDC said. The latest case turned up during an investigation to find out if any other children in the daycare were sick with the same virus. The second child, who is younger than age 5, got sick on Nov 29 with symptoms that included fever, cough, diarrhea, and rhinorrhea.

Like the first case-patient, the second child had no history of recent travel or swine exposure. The child did not seek medical care and has recovered fully, the CDC said.

A respiratory specimen obtained from the child on Dec 7 underwent rRT-PCR testing at the West Virginia Office of Laboratory Services, but the results were inconclusive. Genome sequencing at the CDC confirmed the virus as a novel H3N2 strain containing the M gene from the 2009 H1N1 virus.

The CDC said no other cases have been detected at the daycare or among the two children's contacts. West Virginia health officials and adjacent counties in Maryland are increasing their surveillance for flu-like illnesses, it added.

Though the two infections in West Virginia occurred in children who attended the same daycare, the CDC said the first child probably didn't transmit the virus to the second child, because their symptom onset dates were more than 10 days apart. However, it said the situation suggests limited human-to-human transmission in a daycare setting.

In late November, Iowa health officials reported two infections with the same H3N2 variant in two children who attended the same daycare.

The daycare setting is one of two scenarios that have been involved in the recent novel H3N2 cases, the CDC said. Though 11 of the 12 cases have occurred in children, one of the sick patients was an adult who had occupational exposure to swine.

The CDC said surveillance suggests the novel H3N2 virus is also circulating in swine herds. Of 150 swine influenza viruses that have been sequenced so far, 30 were H3N2 viruses, including 8 that had the M gene from the 2009 H1N1 virus. Further analysis is ongoing and new submissions to GenBank are being added as diagnostic work is completed, the agency said.

Regarding the novel H1N1 virus, the CDC said triple-reassortant viruses—ones that contain genes from avian, swine, and human flu viruses—have been circulating in US swine since the 1990s, and a review of genome sequencing databases suggests the variant that contains the M gene from the 2009 H1N1 virus has been found in US swine since 2010. But this case marks the first detection of such a strain in humans.

Testing shows that the virus is susceptible to the antiviral drugs oseltamivir (Tamiflu) and zanamivir (Relenza), the CDC said.

Given that the 2009 H1N1 virus is commonly circulating in swine and humans, the agency said, it isn't surprising to see viruses that typically transmit among pigs acquire gene segments from the 2009 H1N1 virus. CDC researchers are investigating the implications of the M gene in viruses that normally circulate in swine. So far, experiments suggest it makes flu more transmissible in guinea pigs, but it's not known if the same is true for pigs and humans.

In another development today, a working group from three health groups including the World Health Organization (WHO) recommended standardizing the terminology for the variant influenza viruses to help avoid confusion when referring to seasonal and other flu strains. For the novel H3N2 virus circulating in the United States, the group recommended using influenza A (H3N2)v, with the "v" standing for "variant."

The nomenclature working group also included members from the World Organization for Animal Health (OIE) and the United Nations Food and Agriculture Organization (FAO). The group said the novel H3N2 virus reported in the United States has not been detected anywhere else in the world.

The CDC said that, in line with the naming convention, it is calling the novel H1N1 virus H1N1v and the novel H3N2 virus H3N2v.

In seasonal flu news, the CDC said today that flu activity in the US was still at low levels last week. Doctor's visits for flu-like illness were still below baseline in all regions of the country, and the percentage of respiratory specimens testing positive for flu increased slightly from 1.9% to 2.1%, according to the weekly CDC surveillance report.

Deaths from pneumonia and flu dropped by a small amount and are at a level expected for this time of year, the CDC said, adding that no pediatric flu deaths were reported.

Meanwhile, the flu season in Europe doesn't appear to have started yet, with no sign of sustained transmission in any European Union countries so far, according to an update yesterday from the European Centre for Disease Prevention and Control (ECDC). It said all countries are reporting low flu activity, with 3.6% of respiratory specimens testing positive for flu. Most (88%) of the viruses that have been subtyped so far are seasonal H3N2, the ECDC said.

See also:

Dec 23 CDC weekly flu update

Dec 23 MMWR report

Dec 23 CDC "Have You Heard?" statement

Dec 23 joint statement on nomenclature

Dec 22 ECDC influenza update

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