Antigenically characterized h1n1 viruses. Medical search. Frequent questions

Virus neutralization tests with swine antiserum against swine IAVs of the H1N1, H1N2, and H3N2 subtypes showed an antigenic relationship between both newly discovered isolates and Eurasian avian-like H1N1 swine IAVs from 1998 and 2010, as well as the prototype influenza A(H1N1)pdm09 (pH1N1) A/California/04/2009 virus. (cdc.gov)
Influenza A (H3N2) viruses were the most frequently identified viruses. (cdc.gov)
Influenza A viruses were identified most frequently, with influenza A (H3N2) viruses predominating. (cdc.gov)
Among the 1,824 influenza A specimens subtyped, 95 (5.2%) were influenza A (H1N1)pdm09 and 1,729 (94.8%) were influenza A (H3N2). (cdc.gov)
A H3N2 viruses. (cdc.gov)
We had primarily an influenza A H3N2 virus dominated season. (cdc.gov)
Influenza A virus subtype H3N2 (A/H3N2) is a subtype of viruses that causes influenza (flu). (wikipedia.org)
H3N2 viruses can infect birds and mammals. (wikipedia.org)
Flu vaccines are based on predicting which "mutants" of H1N1, H3N2, H1N2, and influenza B will proliferate in the next season. (wikipedia.org)
In the past ten years, H3N2 has tended to dominate in prevalence over H1N1, H1N2, and influenza B. Measured resistance to the standard antiviral drugs amantadine and rimantadine in H3N2 has increased from 1% in 1994 to 12% in 2003 to 91% in 2005. (wikipedia.org)
An analysis of 13,000 samples of influenza A/H3N2 virus that were collected across six continents from 2002 to 2007 by the WHO's Global Influenza Surveillance Network showed the newly emerging strains of H3N2 appeared in East and Southeast Asian countries about six to nine months earlier than anywhere else. (wikipedia.org)
A 2007 study reported: "In swine, three influenza A virus subtypes (H1N1, H3N2, and H1N2) are circulating throughout the world. (wikipedia.org)
Since the protective ability of influenza vaccines depends primarily on the closeness of the match between the vaccine virus and the epidemic virus, the presence of nonreactive H3N2 SIV variants suggests current commercial vaccines might not effectively protect pigs from infection with a majority of H3N2 viruses. (wikipedia.org)
Avian influenza virus H3N2 is endemic in pigs in China, and has been detected in pigs in Vietnam, contributing to the emergence of new variant strains. (wikipedia.org)
The Hong Kong Flu was a flu pandemic caused by a strain of H3N2 descended from H2N2 by antigenic shift, in which genes from multiple subtypes reassorted to form a new virus. (wikipedia.org)
Both the H2N2 and H3N2 pandemic flu strains contained genes from avian influenza viruses. (wikipedia.org)
Results for A(H3N2) and B/Yamagata viruses suggested that circulating viruses of this subtype and lineage, respectively, had undergone antigenic and/or genetic changes, consistent with the decision by WHO to change recommended strains for the 2015 Southern Hemisphere vaccine. (health.gov.au)
Two types of influenza cause significant disease in humans: types A and B. Influenza A viruses are further classified into subtypes, based on their surface proteins, haemagglutinin (H) and neuraminidase (N). Thus, currently in circulation are subtypes A(H1N1)pdm09 and A(H3N2), although a number of subtypes have been known to infect humans and birds. (health.gov.au)
During 2014, results were reported by reference to the A/California/7/2009 (H1N1pdm09)-like, A/Victoria/361/2012 (H3N2)-like, B/Massachusetts/2/2012-like (Yamagata lineage), and B/Brisbane/60/2008-like (Victoria lineage) viruses that were recommended for the 2014 influenza vaccine. (health.gov.au)
However, H3N2 viruses have predominated in the southeastern region of the United States. (infectioncontroltoday.com)
Influenza A (H1N1)pdm09 (pH1N1), influenza A (H3N2), and influenza B viruses were detected worldwide and were identified sporadically in the United States. (cdc.gov)
Of the 1,728 influenza A viruses, 1,114 (64%) were subtyped: 45 (4%) were pH1N1 viruses, 1,067 (96%) were influenza A (H3N2) viruses, and two (0.2%) were H3N2v viruses. (cdc.gov)
two were associated with an influenza A (H3N2) virus, one was associated with an influenza A virus for which no subtyping was performed, and two were associated with an influenza B virus. (cdc.gov)
Although pH1N1 viruses were identified more frequently than influenza A (H3N2) viruses, the proportion of influenza A (H3N2) viruses reported in Australia increased during August to mid-September. (cdc.gov)
Influenza A (H3N2) viruses predominated in that country, but pH1N1 and influenza B viruses also were reported. (cdc.gov)
In Europe, Japan, and North America, influenza A(H3N2) viruses predominated, but influenza B viruses were more commonly isolated by the end of the season (1). (cdc.gov)
China, Iran, and Israel), influenza B viruses were isolated more frequently than influenza A(H3N2) viruses. (cdc.gov)
Since March 1997, influenza activity has increased in the Southern Hemisphere, and outbreaks and epidemic level activity have been associated with both influenza A(H3N2) and influenza B viruses. (cdc.gov)
Senegal reported isolation of several influenza A(H3N2) viruses during March and April. (cdc.gov)
Most isolations reported from sporadic cases in South Africa during June-August were influenza A(H3N2), but influenza A(H1N1) and influenza B viruses also were detected. (cdc.gov)
In Hong Kong, during April-July, influenza A(H3N2) viruses were more frequently isolated than influenza B viruses, which had predominated during January-March. (cdc.gov)
In Japan, at the end of a season predominated by influenza A(H3N2) viruses, the number of influenza B isolates increased and peaked during March. (cdc.gov)
Influenza B viruses continue to predominate in China, although isolation of influenza A(H3N2) was reported during April, and influenza A(H1N1) was reported during April and May. (cdc.gov)
Germany also reported postseason isolation of influenza A(H3N2) viruses. (cdc.gov)
Influenza A(H3N2) viruses were isolated from sporadic cases in the United States during March and April. (cdc.gov)
As in Europe, influenza B viruses were isolated more frequently than influenza A(H3N2) viruses after mid-February. (cdc.gov)
Based on the results of outpatient and hospital surveillance, influenza A(H1N1)pdm09 and A(H3N2) viruses continued to co-circulate in the Region, with very few influenza B detections having been reported during this season. (flutrackers.com)
Of the 1342 influenza A viruses that were subtyped during week 12/2014, 594 (44%) were A(H1N1)pdm09 and 748 (56%) A(H3N2) (Fig. 2a). (flutrackers.com)
Of the 25 143 influenza A viruses that have been subtyped, 14 835 (59%) were A(H1N1)pdm09 and 10 308 (41%) were A(H3N2). (flutrackers.com)
During Week 9, of the 615 viruses reported by public health laboratories, 437 (71.1%) were influenza A and 178 (28.9%) were influenza B. Of the 286 influenza A viruses subtyped during Week 9, 164 (57.3%) were influenza A(H1N1) and 122 (42.7%) were A(H3N2). (cdc.gov)
In 2006, 657 influenza isolates from Australia were antigenically analysed: 402 were A(H3N2), 24 were A(H1N1) and 231 were influenza B viruses. (health.gov.au)
Continued antigenic drift was seen with the A(H3N2) viruses from the previous reference strains (A/California/7/2004 and A/New York/55/2004) and drift was also noted in some of the A(H1N1) strains from the reference/vaccine strain A/New Caledonia/20/99, although very few A(H1N1) viruses were isolated in Australia in 2006. (health.gov.au)
While it is too early to assess vaccine effectiveness for this season, the good news is that of 1,915 samples referred to the WHOCC in the year-to-date, 97.4% of influenza A(H1N1) isolates, 82.8% of influenza A(H3N2) isolates, and 99.0% of influenza B/Victoria isolates characterised were antigenically similar to the corresponding vaccine components. (thephn.com.au)
samples positive for influenza A are then subtyped as H1N1, H3N2, H5N1, or H7N9. (flutrackers.com)
Antigenic characterization of an H3N2 swine influenza virus isolated from pigs with proliferative and necrotizing pneumonia in Quebec. (microbiologyresearch.org)
We examined the M splicing of human H1N1 and H3N2 viruses by comparing three H1N1 and H3N2 strains, respectively, through reverse transcriptase-polymerase chain reaction (RT-PCR) analyses. (biomedcentral.com)
We randomly selected M sequences of human H1N1, H2N2, and H3N2 viruses isolated from 1933 to 2020 and examined their phylogenetic relationships. (biomedcentral.com)
To confirm the importance of M2 splicing in the replication of H1N1 and H3N2, we treated infected cells with splicing inhibitor herboxidiene and analyzed the viral growth using plaque assay. (biomedcentral.com)
Consequently, herboxidiene treatment dramatically decreased both the H1N1 and H3N2 virus titers. (biomedcentral.com)
This attenuated phenotype was restored by M replacement of H3N2 M in a chimeric H1N1 virus, despite low M2 levels. (biomedcentral.com)

Of the viruses successfully analysed 52% were A(H1N1)pdm09 viruses. (health.gov.au)
A small number of A(H1N1)pdm09 and B/Victoria viruses had highly reduced inhibition to the neuraminidase inhibitors oseltamivir and zanamivir. (health.gov.au)
Since Week 40, influenza A(H1N1)pdm09 has been the predominant virus circulating in all regions. (cdc.gov)
Influenza A(H1N1)pdm09 occurred actively 3 weeks thereafter, and then co-circulated highly with influenza B through the end of March 2020. (health.mil)
Starting at surveillance week 45 (3-9 Nov. 2019), influenza B was the predominant influenza type, followed by high activity of influenza A(H1N1)pdm09 three weeks thereafter. (health.mil)
Both influenza B and influenza A(H1N1)pdm09 were then highly co-circulated through surveillance week 13 (22-28 March 2020). (health.mil)
R1a-B6-Fc fusions of both isotypes gave complete protection against lethal challenge with both pandemic A/California/07/2009 (H1N1)pdm09 and avian influenza A/Vietnam/1194/2004 (H5N1). (frontiersin.org)
Treatment of mice infected with a lethal inoculum of pandemic A/CA/07/2009 (H1N1)pdm09 (pdmCa09) with 4'-FlU alleviated pneumonia. (bvsalud.org)

One reason is that the constantly evolving nature of influenza viruses requires continuous global monitoring and frequent reformulation of the vaccine strains. (who.int)
The information provided by GISN through its participating institutions has identified new influenza threats, substantially helped define the epidemiology of influenza and the molecular evolution of the viruses, and formed the basis for selecting new influenza vaccine strains and for updating diagnostic tests. (who.int)
To improve vaccine effectiveness (VE) against influenza viruses, the strains used in the influenza vaccine need to be updated regularly based on the surveillance findings. (health.mil)
Sensitivity test results, expressed as the concentration of amantadine required to inhibit by 50% the growth of virus (ED 50 ) in tissue culture vary greatly (from 0.1 mcg/mL to 25 mcg/mL) depending upon the assay protocol used, size of virus inoculum, isolates of influenza A virus strains tested, and the cell type used. (nih.gov)
However, due to antigenic drift in influenza viruses, vaccines need to be updated every year to protect against the circulating strains of the virus. (researchsquare.com)
Avian influenza is a viral disease caused by various strains of avian influenza viruses that can be classified as low pathogenic avian influenza (LPAI) or highly pathogenic avian influenza (HPAI). (usgs.gov)
AI strains are divided into two groups based on the pathogenicity of the virus, or the ability of the virus to produce disease. (usgs.gov)
It has been thought that Eurasian strains of avian influenza viruses enter the United States through the Pacific Flyway (Alaska to Baja California) and that this route is the most likely avenue for emerging Eurasian AIV strains to enter North America. (usgs.gov)
AI viruses from both continents, as well as recombinations of both strains, were isolated in Iceland, sometimes from within a single flock of birds, showing that this region is a hotspot of virus movement and genetic reassortment. (usgs.gov)
Its occurrence is unpredictable, the virus spreads rapidly in urban areas and through travel, and populations' lack of immunity to novel influenza strains can result in a rapid spread [ 8 ]. (biomedcentral.com)
Of the four pandemic strains of human influenza A virus observed this century, the 1977 virus strain was very similar in all genes to a 1950 isolate. (microbiologyresearch.org)

We have previously described R1a-B6, an alpaca-derived single domain antibody (nanobody), that is capable of potent cross-subtype neutralization in vitro of H1N1, H5N1, H2N2, and H9N2 influenza viruses, through binding to a highly conserved epitope in the influenza hemagglutinin stem region. (frontiersin.org)

Both viruses were antigenically and genetically characterized. (cdc.gov)
Most influenza viruses characterized during this period were genetically or antigenically similar to the reference viruses representing vaccine components recommended for production in the 2016-17 Northern Hemisphere influenza vaccines. (cdc.gov)
The majority of these were antigenically and genetically similar to the WHO recommended reference strain for the 2014 Southern Hemisphere influenza vaccine. (health.gov.au)
The mechanism by which latent viruses, such as genetically transmitted tumor viruses ( PROVIRUSES ) or PROPHAGES of lysogenic bacteria, are induced to replicate and then released as infectious viruses. (lookformedical.com)

The new subtypes arose in pigs coinfected with avian and human viruses and were soon transferred to humans. (wikipedia.org)
Influenza B viruses are not classified into subtypes. (health.gov.au)
Amantadine inhibits the replication of influenza A virus isolates from each of the subtypes, i.e. (nih.gov)
Two subtypes of nucleoproteins (NP) of influenza A viruses. (microbiologyresearch.org)

Pigs can carry human influenza viruses, which can combine (i.e. exchange homologous genome subunits by genetic reassortment) with H5N1, passing genes and mutating into a form which can pass easily among humans. (wikipedia.org)
This paper, and the accompanying Diagram, describe many aspects of the influenza vaccine process including important similarities and differences in how seasonal human influenza viruses and H5N1 viruses are handled. (who.int)
Before 2004, GISN primarily focused on seasonal influenza viruses for vaccine development but since 2004, has expanded its scope to include H5N1 viruses because this virus constitutes an unusually serious pandemic risk. (who.int)
Therefore, WHO now reviews the available antigenic and genetic data on animal and human H5N1 viruses in addition to the analyses of seasonal vaccine stains and has developed and made H5N1 candidate vaccine viruses available to vaccine producers so they can work on developing safe and effective human H5N1 vaccines for potential productioni. (who.int)
Some of these H5N1 candidate vaccine viruses have been used by manufacturers to produce human influenza H5N1 vaccines, some of which have been tested in clinical trials. (who.int)
Influenza A(H5N1), a strain of influenza virus that usually infects only birds, was isolated from a 3-year-old child in Hong Kong who died in May of multiple complications including Reye syndrome during an acute respiratory illness. (cdc.gov)
Currently, there is concern that the avian A(H5N1) virus that has infected and killed millions of poultry in many countries will undergo such changes or naturally mutate to make it easily transmissible in humans and hence trigger a pandemic. (health.gov.au)

Isolates were identified as antigenically similar to the reference strain if the test samples had a titre that was no more than 4-fold different from the titre of the homologous reference strain. (health.gov.au)
The B viruses isolated were predominately of the B/Victoria-lineage and similar to the reference/vaccine strain B/Malaysia/2506/2004. (health.gov.au)
However, AIV also frequently infects domestic poultry and wild ducks in Europe and Africa and migrating wild birds that use the east Atlantic flyway may also risk introducing Eurasian strain viruses to North America via this route. (usgs.gov)
The mutation detected in the nuclear M protein, responsible for the resistance to amantadine compounds, similar to that found in the AH5N1 Hong Kong virus from 1997, caused concern due to the high lethality seen with this kind of strain, and because of the high infectivity of this new virus [ 8 ]. (biomedcentral.com)
The influenza virus constantly mutates, limiting the impact of protection by vaccination, and immunity conferred in one pandemic influenza period will not reliably prevent new infections by an antigenically drifted strain [ 9 ]. (biomedcentral.com)
The 2009 H1N1 pandemic strain is a reassortant of avian, human, and swine influenza viruses. (virology.ws)
To explore the physiological role of the various levels of M2 protein in pathogenicity, we challenged C57BL/6 mice with the H1N1 WSN wild-type strain, mutant H1N1 (55T), and chimeric viruses including H1N1 + H3wt and H1N1 + H3mut. (biomedcentral.com)

In addition, Hong Kong reported sporadic isolation of influenza A(H1N1) virus during June-August. (cdc.gov)
I. Serological evidence of infection in swine in Great Britain with an influenza A virus antigenically like human Hong Kong/68 virus. (microbiologyresearch.org)

We report a zoonotic infection of a pig farmer in the Netherlands with a Eurasian avian-like swine influenza A(H1N1) virus that was also detected in the farmed pigs. (cdc.gov)
In this study, we report an infection with a Eurasian avian-like H1N1 swine IAV in a pig farmer and his pigs in a herd in the Netherlands. (cdc.gov)
One human infection with a novel influenza A virus was reported. (cdc.gov)
Targeted surveillance for influenza A(H7N9) identified 21 cases of infection with this virus in Guangzhou, China, during April 1, 2013?March 7, 2014. (flutrackers.com)
During February?May 2013, the initial outbreak of human infection with avian influenza A(H7N9) virus in China resulted in 133 cases ( 1 ). (flutrackers.com)
Influenza A(H7N9) virus reemerged in southern China in October 2013 and had caused 85 laboratory-confirmed cases of infection in Guangdong Province as of March 7, 2014. (flutrackers.com)
Vaccination is the primary intervention used to curb influenza virus infection, and the WHO recommends immunization for at-risk individuals to mitigate disease. (mdpi.com)
Seasonal influenza vaccination is considered the main strategy to protect against influenza viruses, combat influenza infection, and reduce disease severity. (health.mil)
Vaccine-induced antibody and T cell responses correlated with protection against lethal influenza virus infection. (researchsquare.com)
Moreover, antibody responses induced by influenza virus vaccines are usually short-lived and less cross-reactive against antigenically drifted virus variants than those induced by a natural influenza virus infection 1 . (researchsquare.com)
However, RIDTs have limited sensitivity to detect influenza virus infection and negative test results should be interpreted with caution given the potential for false negative results. (cdc.gov)
Some RIDTs distinguish between influenza A or B virus infection while others do not. (cdc.gov)
However, due to th e limited sensitivities and predictive values of RIDTs, negative results of RIDTs do not exclude influenza virus infection in patients with signs and symptoms suggestive of influenza. (cdc.gov)
RIDTs can be useful to identify influenza virus infection as a cause of respiratory outbreaks in any setting, but especially in institutions (i.e., nursing homes, chronic care facilities, and hospitals), cruise ships, summer camps, schools, etc. (cdc.gov)
However, negative RIDT results do not exclude influenza virus infection as a cause of a respiratory outbreak because of the limited sensitivity of these tests. (cdc.gov)
Testing respiratory specimens from several persons with suspected influenza will increase the likelihood of detecting influenza virus infection if influenza virus is the cause of the outbreak. (cdc.gov)
Clinical signs and symptoms consistent with influenza o Having clinical signs and symptoms consistent with influenza increases the pre-test probability of influenza virus infection, which increases the reliability of a positive RIDT result. (cdc.gov)
The ability of a pathogenic virus to lie dormant within a cell (latent infection). (lookformedical.com)
Once-daily oral treatment of ferrets with 2 mg/kg 4'-FlU initiated 12 hours after infection rapidly stopped virus shedding and prevented transmission to untreated sentinels. (bvsalud.org)
With a global decline in the COVID-19 control, the infection rate of influenza virus is gradually increasing. (bvsalud.org)

Among these, 2,103 were positive for influenza ( Figure 2 ), including 1,930 (91.8%) that were positive for influenza A viruses and 173 (8.2%) that were positive for influenza B viruses. (cdc.gov)
The most frequently identified influenza virus type reported by public health laboratories during week 46 was influenza A. The percentage of respiratory specimens testing positive for influenza in clinical laboratories is increasing. (cdc.gov)
WHO and NREVSS collaborating laboratories, which include both public health and clinical laboratories located in all 50 states, Puerto Rico, and the District of Columbia, report to CDC the total number of respiratory specimens tested for influenza and the number positive for influenza by virus type. (cdc.gov)
Of the 9,154 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 2,866 (31.3%) were positive for influenza. (cdc.gov)
Of the 3,209 specimens positive for influenza during the summer months of 2014, a total of 1,728 (54%) were influenza A viruses, and 1,481 (46%) were influenza B viruses. (cdc.gov)
Data from clinical laboratories (the percentage of specimens tested that are positive for influenza virus) are used to monitor whether influenza activity is increasing or decreasing. (cdc.gov)

In certain cases, amantadine is also known to prevent virus assembly during virus replication. (nih.gov)
This was possible in the lab because the molecular biology of replication is well characterised and that measles virus is polyploid allowing the engineering of a tri-segmented genome that can replicate and be packaged into virions. (virology.ws)
However, a lower M2 expression only attenuated H1N1 virus replication and in vivo pathogenicity. (biomedcentral.com)

The assay has been used to claim that these common sequences were antigenically indistinguishable from the current H1N1 vaccine target, A/California/7/2009, which was used to justify the decision to keep the vaccine target unchanged. (proboards.com)

Among the 97 influenza B viruses for which lineage was determined, 39 (40.2%) belonged to the B/Yamagata lineage and 58 (59.8%) belonged to the B/Victoria lineage. (cdc.gov)
In addition, the lineage of 169 influenza B viruses has been determined: 155 (92%) belonged to the B/Yamagata lineage (the lineage of the B virus recommended by WHO for inclusion in trivalent seasonal influenza vaccines) and 14 (8%) to the B/Victoria lineage. (flutrackers.com)

The human H1N1v isolate was named A/Netherlands/Gent-193/2019, and the swine H1N1 isolate was named A/swine/Netherlands/Gent-193/2019. (cdc.gov)
The estimated VE (46%) indicated that the influenza vaccine during the 2019-2020 influenza season was moderately effective against these influenza viruses. (health.mil)
Influenza surveillance conducted by DODGRS during the 2019-2020 influenza season identified circulating influenza virus (sub)types, provided timely data on the genetic characteristics of the circulating viruses, and estimated influenza VE. (health.mil)
The influenza vaccine was moderately effective against influenza viruses during the 2019-2020 influenza season. (health.mil)

An example of the evolutionary importance of reassortment is the exchange of RNA segments between mammalian and avian influenza viruses that give rise to pandemic influenza. (virology.ws)
This study defines the mechanistic foundation for high sensitivity of influenza viruses to 4'-FlU and supports 4'-FlU as developmental candidate for the treatment of seasonal and pandemic influenza. (bvsalud.org)

Zoonotic infections with such viruses, which are then termed H1N1 variant (H1N1v) viruses, occur sporadically. (cdc.gov)
six of which operate year-round: 1) U.S. World Health Organization (WHO) collaborating laboratories, 2) the National Respiratory and Enteric Virus Surveillance System, 3) reports of human infections with novel influenza A viruses, 4) the U.S. Outpatient Influenza-Like Illness Surveillance Network, 5) the 122 Cities Mortality Reporting System, and 6) the Influenza-Associated Pediatric Mortality Reporting System. (cdc.gov)
During May 18–September 20, two human infections with H3N2v viruses were reported by Ohio. (cdc.gov)
One reason people may not perceive the flu as being serious is that cases of the "stomach flu" are mistaken for influenza virus infections. (flutalk.net)
Next generation antivirals are needed to treat seasonal infections and prepare against zoonotic spillover of avian influenza viruses with pandemic potential. (bvsalud.org)
Nine definite enteric E. coli pathotypes have been well characterized, causing diseases ranging from various gastrointestinal disorders to urinary tract infections. (preprints.org)

Continued surveillance of swine influenza A viruses is needed for risk assessment in humans and swine. (cdc.gov)
U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) laboratories include both clinical and public health laboratories throughout the United States that carry out virologic surveillance for influenza. (cdc.gov)
In addition, each year some cases of influenza C are isolated from humans, but as these viruses tend not to cause severe disease, they are not a focus of surveillance. (health.gov.au)
METHODS AND FINDINGS: We aggregated published data from a systematic review and unpublished data from surveillance platforms to generate global meta-analytic estimates for the proportion of acute respiratory hospitalizations associated with influenza viruses among adults. (bvsalud.org)
Influenza surveillance in Australia is based on laboratory isolation of influenza viruses, sentinel general practitioner reports of influenza-like illness, and absenteeism data from a major national employer. (health.gov.au)
In response to the influenza A(H7N9) outbreak, PUE surveillance was enhanced in April 2013 by implementing laboratory testing specific for influenza A(H7N9) virus ( 3 ). (flutrackers.com)
Because of the changing nature of these viruses, it is crucial to conduct annual surveillance to determine the circulating viruses and to detect changes in the viruses during the influenza season. (health.mil)
The USGS National Wildlife Health Center (NWHC) in collaboration with multiple partners conducts research into the ecology of avian influenza virus and surveillance for highly pathogenic avian influenza (HPAI) viruses leading to several significant findings towards early detection and response to HPAI. (usgs.gov)
The USGS National Wildlife Health Center, in collaboration with the National Institutes of Health Centers of Excellence for Influenza Research and Surveillance (CEIRS), the University of Iceland, and other partners, has explored the ecology and movement of AI viruses in the North Atlantic region since 2010. (usgs.gov)

All influenza viruses tested to date have been sensitive to the antiviral drugs oseltamivir, zanamivir, and peramivir. (cdc.gov)
and describe antiviral treatment recommendations for patients with suspected or confirmed influenza for the 2022-2023 season, including during community co circulation of influenza viruses and SARS-CoV-2. (cdc.gov)
Viruses were characterised by their antigenic, genetic and antiviral drug resistance properties. (health.gov.au)
The GISRS network, established in 1952, monitors changes in influenza viruses with the aim of reducing the impact of influenza through the use of vaccines and antiviral medications. (health.gov.au)
Although antiviral drugs such as Oseltamivir are available to control the spread of the virus their effectiveness is limited in treating patients with influenza ( 5 , 6 ). (frontiersin.org)
Our findings provide insights into virus adaptation processes in humans and highlights splicing regulation as a potential antiviral target. (biomedcentral.com)

A quantitative relationship between the in vitro susceptibility of influenza A virus to amantadine and the clinical response to therapy has not been established in man. (nih.gov)
Influenza viruses with reduced in vitro sensitivity have been shown to be transmissible and to cause typical influenza illness. (nih.gov)
The Yanagi group in Japan managed to segment the naturally nonsegmented measles virus into three segments and the recovered viruses were viable in vitro. (virology.ws)

In addition, public health laboratories also report the influenza A subtype (H1 or H3) and influenza B lineage information of the viruses they test and the age or age group of the persons from whom the specimens were collected. (cdc.gov)
All virus isolates received at the Centre were re-passaged in cell culture (Madin-Darby Canine Kidney [MDCK] cells) and virus isolation was also attempted on a selection of original clinical specimens received. (health.gov.au)
Together, this network processes an estimated 150,000 to 200,000 respiratory specimens per year with approximately 5000 viruses voluntarily shared by the NICs undergoing extensive antigenic and genetic characterization among the WHO CCs. (who.int)

These sequences from vaccine breakthrough patients provide additional data indicating the current vaccine no longer offers significant protection from the H1N1 currently in circulation. (proboards.com)

There are various ways to achieve genetic variation and gene expression, and viruses explore all aspects of this space. (virology.ws)
Since mammalian influenza A viruses change annually by genetic drift, this reappearance could only be attributed at that time to conservation of the virus in a frozen state. (microbiologyresearch.org)
Genetic reassortment between avian and human influenza A viruses in Italian pigs. (microbiologyresearch.org)
Deoxyribonucleic acid that makes up the genetic material of viruses. (lookformedical.com)
Viruses whose genetic material is RNA. (lookformedical.com)

The predominant virus has varied by week, region, and even between states within the same region. (cdc.gov)

The EuroFlu bulletin describes and comments on influenza activity in the 53 Member States in the WHO European Region to provide information to public health specialists, clinicians and the public on the timing of the influenza season, the spread of influenza, the prevalence and characteristics of circulating viruses (type, subtype and lineage) and severity. (flutrackers.com)
Prevalence of antibodies to swine influenza virus, porcine adenovirus type 4 and Haemophilus pleuropneumoniae in Quebec pig farms with respiratory problems. (microbiologyresearch.org)

Eurasian avian-like swine influenza A(H1N1) viruses (IAVs) are entirely derived from a precursor virus of avian origin ( 1 ) and have been enzootic in the swine population in Europe since 1979 and in Asia since 1993. (cdc.gov)
Since 1986, several human cases of Eurasian avian-like H1N1 swine IAV have been reported in Europe ( 2 - 4 ) and China ( 3 , 5 ). (cdc.gov)
These events reflect the possibility of Eurasian avian-like H1N1 swine IAV transmission from swine to humans. (cdc.gov)
Initial analyses by multiplex real-time reverse transcription PCRs ( 6 ) and whole-genome next-generation sequencing ( 7 ) of both isolates confirmed that all genome segments were closely related to those of Eurasian avian-like H1N1 swine IAVs. (cdc.gov)
A BLAST homology search ( http://www.fludb.org ) with both whole genomes showed highest nucleotide identities (96%) for hemagglutinin (HA) and neuraminidase with clade 1C.2.2 Eurasian avian-like H1N1 swine IAVs isolated in Germany and the Netherlands during 2011-2012. (cdc.gov)

Avian influenza viruses (AIV) are classified by a combination of two groups of proteins found on the surface of the virus: hemagglutinin proteins (H), of which there are 18 (H1-H18), and neuraminidase proteins (N), of which there are 11 (N1-N11). (usgs.gov)
The surface glycoproteins hemagglutinin (HA) and neuraminidase (NA) involved in receptor binding and virus release are used to classify IAVs. (biomedcentral.com)

The vaccine breakthrough sequences are consistent with the UK data which showed that the H1N1 vaccine only protected 50% of recipients in the first half of the 2011/2012 season. (proboards.com)

Present vaccination strategies for swine influenza virus (SIV) control and prevention in swine farms typically include the use of one of several bivalent SIV vaccines commercially available in the United States. (wikipedia.org)
The results of that data examination in turn allow these experts to select candidate vaccine viruses that might be included -- if they pass additional testing -- in the following season's vaccines. (who.int)
This review will focus on current and future efforts in developing universal vaccines targeting different viruses at the genus and/or family levels, with a special focus on henipaviruses, influenza viruses, and coronaviruses. (bvsalud.org)
It is evident that strategies for developing broad-spectrum vaccines will be virus-genus or family specific, and it is almost impossible to adopt a universal approach for different viruses. (bvsalud.org)

The sows of this herd (n = 420) were vaccinated against swine IAVs with Respiporc FLU3 vaccine (Ceva, https://www.ceva.com ), but the farmer and animal caretaker were not recently vaccinated against human seasonal influenza viruses. (cdc.gov)
Influenza A viruses (IAVs) of the Orthomyxoviridae family infect various species, including mammals and birds. (biomedcentral.com)

In Madagascar, increased activity during May was associated with influenza B viruses. (cdc.gov)
Initially, preseason isolates and outbreaks in June among school-aged children were associated with influenza B viruses. (cdc.gov)

CDC received isolates of influenza B virus from sporadic cases each month from March to June. (cdc.gov)
Mexico reported isolates of influenza B virus in March. (cdc.gov)

Influenza A has remained the dominant virus type in circulation across the Region since the start of weekly monitoring in week 40/2013. (flutrackers.com)

Having previously identified oral efficacy of the nucleoside analog 4'-Fluorouridine (4'-FlU, EIDD-2749) against SARS-CoV-2 and respiratory syncytial virus (RSV), we explored activity of the compound against seasonal and highly pathogenic influenza (HPAI) viruses in cell culture, human airway epithelium (HAE) models, and/or two animal models, ferrets and mice, that assess IAV transmission and lethal viral pneumonia, respectively. (bvsalud.org)

Next, we determined the effects of single nucleotide variations on M splicing by generating mutant viruses harboring the 55C/T variant through reverse genetics. (biomedcentral.com)

Data from public health laboratories are used to monitor the proportion of circulating influenza viruses that belong to each influenza subtype/lineage. (cdc.gov)

During April, the Czech Republic reported outbreaks of influenza A(H1N1) virus among schoolchildren. (cdc.gov)
Seasonal influenza is defined as predictable outbreaks of respiratory disease caused by various influenza viruses that spread from person to person. (csis.org)
With the on-going European outbreaks of HPAI there is a risk of moving these viruses to North America as well. (usgs.gov)

Seasonal influenza viruses flow out of overlapping epidemics in East Asia and Southeast Asia, then trickle around the globe before dying off. (wikipedia.org)
Another reason is that the rapid spread of these viruses during seasonal epidemics, as well as the occasional pandemic, means that each step in the vaccine process must be completed within very tight time frames if vaccine is to be manufactured and delivered in time. (who.int)
Influenza virus continues to be a major public health concern, causing both annual epidemics and occasional pandemics ( 1 ). (frontiersin.org)
Influenza A virus is a main cause of winter epidemics that results in increments in respiratory morbidity. (biomedcentral.com)
Influenza viruses are highly contagious and can cause seasonal epidemics, manifesting as an acute febrile illness with variable degrees of severity, ranging from mild fatigue to respiratory failure and death. (medscape.com)

In domestic birds, however, some AI viruses can be more pathogenic and mutation or recombination of a virus acquired from wild birds can increase disease potential. (usgs.gov)
Highly pathogenic AI viruses have been frequently found in wild and domestic European birds, significantly in 2006, and annually since then. (usgs.gov)

Splicing of PB2 generates PB2-S1, which was only identified in pre-2009 human H1N1, and may inhibit the retinoic acid-inducible gene I signaling pathway [ 4 ]. (biomedcentral.com)

However, other hosts appear capable of similar coinfection (e.g., many poultry species), and direct transmission of avian viruses to humans is possible. (wikipedia.org)
The ancestral hosts for influenza A viruses are aquatic birds, however, it has also been established in some mammals, such as humans and pigs. (health.gov.au)
Despite several vaccine candidates available on the market, influenza virus is responsible for severe illness in humans, with a substantial global death toll every year (https://gis.cdc.gov/grasp/fluview/flu_by_age_virus.html). (researchsquare.com)
Influenza viruses cause epidemic disease (influenza virus types A and B) and sporadic disease (type C) in humans. (medscape.com)

1 In HI assays, viruses were tested for their ability to agglutinate red blood cells in the presence of ferret antisera previously raised against reference viruses. (health.gov.au)

Influenza-virus-mediated disease can be associated with high levels of morbidity and mortality, particularly in younger children and older adults. (mdpi.com)
AIM OF THE STUDY: Influenza is an acute infectious respiratory disease caused by the influenza virus, which has high annual morbidity and mortality worldwide. (bvsalud.org)
Influenza viruses cause a broad array of respiratory illnesses responsible for significant morbidity and mortality in children. (medscape.com)

The Centre also undertook primary isolation of vaccine candidate viruses directly into eggs. (health.gov.au)
Other countries reporting isolation of influenza A(H1N1) from sporadic cases include Germany, Norway, and the United Kingdom. (cdc.gov)
We report here the isolation of swine influenza A viruses with haemagglutinin and nucleoprotein genes which are virtually identical to those of the human virus that circulated in 1975. (microbiologyresearch.org)

Therefore, there is an urgent need for a better cost-effective influenza vaccine which can induce antigenically broader and long-lasting immune response. (researchsquare.com)
Once injected into our arms, the pieces of dead virus stimulate our bodys immune response to produce antibodies, which act as a defence that can rapidly swing into action when a live flu virus infects our nose and throat. (flutalk.net)

This report summarizes worldwide influenza activity during March-August 1997, as reported through WHO, the WHO international network of collaborating laboratories, and U.S. state and local health departments, and characterizes influenza isolates collected during March-July. (cdc.gov)

In a pandemic, a new influenza virus emerges and infects the human population which has little or no pre-existing immunity ( 2 , 3 ). (frontiersin.org)

However, the current vaccine has limited efficacy against the H1N1 currently circulating in western Pennsylvania and throughout the northern hemisphere. (proboards.com)

Protective anti-influenza immunity often correlates with antibody responses to influenza surface glycoproteins, particularly hemagglutinin (HA), the main antigenic determinant on the surface of both influenza virus and infected cells. (researchsquare.com)
Although FF possesses a prominent clinical therapeutic effect, seldom pharmacological studies have been reported on its anti-influenza B virus (IBV) activity. (bvsalud.org)

This research has demonstrated the importance of the migratory bird flyways in this region to the intercontinental movement of viruses between Europe and North America. (usgs.gov)

Anatomy12

Organisms124

Diseases24

Chemicals and Drugs35

Analytical, Diagnostic and Therapeutic Techniques and Equipment21

Phenomena and Processes44

Disciplines and Occupations1

Information Science3

Health Care3

H3N250

Pdm098

Strains11

H2N21

Genetically4

Subtypes4

H5N17

Strain7

Hong Kong2

Infection20

Positive for influenza6

Replication3

California1

Victoria2

20194

Pandemic influenza2

Infections6

Surveillance9

Antiviral6

Vitro3

Specimens3

Currently in circulation1

Genetic5

Predominant virus1

Prevalence2

Eurasian5

Neuraminidase2

Sequences1

Vaccines4

IAVs2

Associated with influenza2

Isolates of influenza B vir2

Circulation1

Pneumonia1

Variant1

Lineage1

Outbreaks3

Epidemics5

Pathogenic2

Inhibit1

Humans4

Reference viruses1

Morbidity and morta3

Isolation3

Immune response2

Influenza activity1

Infects1

Efficacy1

Anti-influenza2

North America1