Dec 09, 2011 in response to recent human infections with novel influenza viruses, cdc would like to convey the following information. The structure of the influenza virus neuraminidases, the spatial organization of their active site, the mechanism of carbohydrate chains desialylation by neuraminidase, and its role in the. The categories refer to molecular characteristics of a virus and the virus ability to cause disease and mortality in chickens in a laboratory setting cdc pdf 2. Eine virusausscheidung vor symptombeginn ist moglich. Collecting, preserving and shipping specimens for the.
There is no evidence to suggest that the consumption. Avian influenza virus detection and quantitation by real. The laboratory diagnosis of influenza uses a wide range of techniques including rapid immunoassays, immunofluorescence techniques, virus culture methods, and increasingly sophisticated molecular assays. The season came to a first, intense peak in the northern part of the country during the christmas holidays, followed by a second peak in the south in february. Cdc works to improve global control and prevention of seasonal and novel influenza, including avian influenza viruses, and works to improve influenza pandemic preparedness and response. Now we know that it is caused by an rna virus of the family orthomyxoviridae the influenza viruses. Although they emerged more than 90 years apart, the influenza viruses responsible for the pandemics of 1918 and 2009 share a structural detail that makes both susceptible to neutralization by the same antibodies. Influenza virus characterisation summary europe, july 2019. The influenza virus that wreaked worldwide havoc in 19181919 founded a viral dynasty that persists to this day, according to scientists from the national institute of allergy and infectious diseases niaid, part of the national institutes of health.
Right size influenza virologic surveillance roadmap i. The symposium brought together people from different disciplines working with the common objective of reducing the ravages of influenza and to expose them to the totality of the problem of influenza. The q26 and q39 viruses were both double reassortant avian influenza viruses h7 and h9 subtype, as was the early h7n9 virus figure. Influenza a virus, influenza b virus, and influenza c virus, respectively table 10. The genetic properties of seven coldadapted variants of influenza virus a were compared with those of nine lfluorouracil 5fuinduced ts mutants. Ecology and biochemical properties of avian influenza viruses history of the h5n1 avian influenza virus surveillance strategies for avian influenza references and information sources. It is an orthomyxovirus that contains the glycoproteins haemagglutinin and neuraminidase. Avian influenza a viruses are classified into the following two categories. This strain is often called swine flu by the public media. The influenza season of 20152016 was dominated by influenza ah1n1pdm09, with a small wave of influenza bvictoria towards the end of the season. Avian influenza viruses exhibit host adaptation to birds.
The latter are composed of key genes from the 1918 virus, updated by subsequentlyincorporated avian influenza genes that code for novel surface proteins, making the 1918 virus indeed the mother of all pandemics. The type with the greatest risk is highly pathogenic avian influenza hpai. H7n9 virus is a low pathogenic avian influenza a virus and does not cause identifiable illness or death in poultry. A pandemic occurs when an influenza virus which was not previously circulating. Influenza virus infection begins with attachment of the viral hemagglutinin ha protein to a cell surface receptor, followed by internalization of the virus into cells, facilitated by endocytosis marsh and helenius, 2006, matlin et al. A birdadapted strain of h5n1, called hpai ah5n1 for highly pathogenic avian influenza virus of type a of subtype h5n1, is the highly pathogenic causative agent of h5n1 flu, commonly known as avian influenza bird flu. Diese drei virustypen losen unterschiedlich schwere krankheitsbilder aus. Phylogenetic analysis demonstrated that the virus is a reassortant of h5n8 clade 2. Influenza virus entry via the olfactory nerve might occur more frequently since orns are located in the nasal cavity, which is the primary replication site for most influenza viruses. Avian influenza viruses normally spread between birds. Public health monitoring plan for usdaaphis responders to detections of avian influenza virus in poultry cdc pdf 325 kb, 17 pages external.
Bird flu is similar to swine flu, dog flu, horse flu and human flu as an illness caused by strains of influenza viruses that have adapted to a specific host. Surveillance of influenza and other respiratory viruses, including novel respiratory viruses, in the united kingdom. Avian influenza viruses can survive indefinitely when frozen. Overall, the season had high activity but slightly fewer laboratoryconfirmed cases compared to the previous, intense season.
The fluview interactive novel flu a tool reflects the most current case counts for variant virus infections reported in the united states since 2010. Pandemic influenza preparedness and mitigation in refugee and displaced populations pdf. Above all else, bird flu, better named avian influenza, is an animal health problem. Seroprevalence of highly pathogenic avian influenza h5n1. Heinrich pette institute, leibniz institute for experimental virology, hamburg, germany i. Dec 15, 2002 protein phenotypic variant type name substitution present comments citation. Development and distribution of candidate vaccine viruses for avian influenza ah7n9 pdf, 103kb 2 may 20. Bird flu avian influenza is a disease caused by strains of influenza virus that primarily affects birds. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Genetic variation among influenza viruses 1st edition. The 5fu mu tants had previously been placed into seven complementationrecombination groups.
Selfobservation instructions for demobilizing bird flu. Who provisional recommendation on influenza ah7n9 vaccine virus as of 31 may 20 pdf, 87kb 31 may 20. Avian influenza, known informally as avian flu or bird flu, is a variety of influenza caused by viruses adapted to birds. Jan 04, 20 the 201220 influenza season in norway is emerging and above the epidemic threshold. Influenza a is caused by specified viruses that are. A virus is defined as hpai or lpai by its ability to cause severe disease in intravenously inoculated young chickens in the laboratory, or by its. Introduction of val473leu and pro598leu substitutions in the recombinant virus acambodia.
Who candidate vaccine viruses for avian influenza ah7n9. Type b and c influenza viruses are not known to infect poultry or do not cause disease in poultry. Influenza strain details for awsn1933h1n1 strain information. Genetic variation among influenza viruses documents the proceedings of icnucla symposium held in salt lake city, utah, 8 march 1981. Instructions for the classification of influenza viruses and candidate. Shedding and transmission of novel influenza virus ah1n1. Of all viruses in the vast avian influenza pool, h5n1 is of particular concern for human health for two reasons. Influenza in sweden 20162017 season folkhalsomyndigheten. Epidemiology of human infections with avian influenza a. Continuing progress towards a unified nomenclature system for the highly pathogenic h5n1 avian influenza viruses march 2009. The three different influenza viruses that are circulating.
Influenza virus as an enveloped virus is relatively vulnerable to damaging. Influenza virushost interactome screen as a platform for. Information for specific groups avian influenza flu. Highly pathogenic avian influenza hpai caused by the ah5n1 influenza subtype in animal populations, particularly wild waterfowl and domestic poultry such as chickens and ducks, poses a continuing global human public health risk. Shinya k1, ebina m, yamada s, ono m, kasai n, kawaoka y. The avian virus is inactivated more quickly in manure, but can survive for up to 2 weeks in feces on cages. Avian influenza viruses are most frequently detected from ducks anseriformes, particularly from dabbling ducks, such as mallards anas platyrhynchos. Novel reassortant highly pathogenic avian influenza ah5n2. A case of human infection with a novel influenza a virus confirmed by cdcs influenza laboratory. Avian influenza virus infections in humans are of public health concern, not only because of the illness they may cause, but because of their pandemic potential. New influenza virus affects cattle, pigs sciencedaily. Due to the constantly changing com position of influenza viruses in circulation.
The incursion of influenza ah1n1pdm09 virus was detected by norways active serosurveillance of its pig population in 2009. When avian influenza infects humans, symptoms may range from mild upper respiratory infection fever and cough to severe pneumonia, acute respiratory distress syndrome difficulty breathing, shock and even death. Winter 2012 4 executive summary although influenza activity in the uk rose to only low levels in the 2012 season, activity was prolonged and reached levels higher than those seen in 201112. Summary of status of development and availability of avian influenza ah7n9 candidate vaccine. As the new influenza virus consists of components of different influenza viruses e. Ambient influenza and avian influenza virus during dust. Among cases for which data are available, 82% occurred in patients who had exposure to live animals such as poultry or swine, including during visits to live. Influenza research database strain amallardsweden982002. Structural characterization of the 1918 influenza virus h1n1. Realtime rtpcr rrtpcr is a relatively new technology that has been used for avian influenza ai virus detection since the early 2000s for routine surveillance, during outbreaks, and for. Surveillance of influenza and other respiratory viruses. Avian influenza virus an overview sciencedirect topics.
At that time, only a few laboratories were capable of characterizing the. The genome of a virus may be either dna or rna it is rna in influenza and it contains the instructions for making new viruses. The norwegian national influenza pandemic preparedness plan. On average, the authors detected viral rna copies for 6. Cdc interim guidance for landfill workers in the united states disposing of poultry carcasses during outbreaks of highly pathogenic avian influenza cdc pdf 408 kb, 4 pages external.
H14, h6 and h816 are not defined as avian influenza and are not notifiable. We detected a novel reassortant highly pathogenic avian influenza ah5n2 virus in 3 poultry farms in egypt. Currently only two classes of antiviral drugs have been approved for the treatment and prevention of influenza. Cns invasion and associated disease caused by influenza viruses might thus not only be a complication of a severe lower respiratory tract infection. Influenza a virus subtype h5n1 ah5n1 is a subtype of the influenza a virus which can cause illness in humans and many other animal species. The first was an influenza b virus that contained a previously unreported na mutation d197e 4244, while the other was a seasonal ah1n1 virus with an h275y na mutation that was resistant to oseltamivir approximately 900fold higher ic 50 compared to a sensitive wildtype virus but retained sensitivity to zanamivir. Avian influenza virus aiv h9n2 have widely circulated in the world since its first detection from turkeys in 1966. In december 2005, at the request of the senate majority leader, the congressional budget office cbo prepared an assessment of the possible macroeconomic effects of an avian flu pandemic. An influenza pandemic requires a special plan, in view of the special challenges the national health service and authorities will be facing both when a pandemic threatens and when the population is attacked by the disease. Reported infections with variant influenza viruses in the. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Environmental protection agency eparegistered disinfectants that may be used against avian influenza virus in.
Influenza a viruses with high pathogenicity in birds other than poultry, including wild birds, are also notifiable. A case meeting the clinical criteria and epidemiologically linked to a confirmed case, but for which no confirmatory laboratory testing for novel influenza virus infection has been performed. Aug 20, 2008 influenza virus is highly contagious and can cause severe respiratory illness and death. Some avian influenza viruses have been associated with greater numbers of human infections and more serious illnesses in people and therefore may pose a greater known public health risk.
These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Influenza on the increase in norway medical xpress. Occurrence and spread of influenza ah1n1pdm09 virus. Summary of status of development and availability of avian influenza ah7n9 candidate vaccine viruses pdf, 128kb 23 may 20. Weekly number of the different influenza viruses is displayed as stacked bars, and influenza virus positivity rates of sentinel specimens and all lab testing, respectively, are shown as line graphs. Most human cases have originated from infection with eurasian h5 hpai virus agooseguangdong lineage, and, most recently, h7n9 lpai virus chinese lineage. Low pathogenicity nonh5 and nonh7 influenza a viruses i. Of the three types of influenza virus, type a infects a wide range of avian and mammalian species and can be further classified into subtypes according to the serological reactivity of its surface glycoprotein antigens, hemagglutinin ha and neuraminidase na. Background although the effective transmission of the h5n1 virus from human to human has yet to be further observed, humans are at increased risk of a pandemic caused by h5n1.
Surveillance for influenza viruses was formally established through the world health organization who in the 1940s. The virus carried genome segments of a pigeon h9n2 influenza virus detected in 2014, a nucleoprotein segment of contemporary chicken h9n2 viruses from egypt, and hemagglutinin derived from the 2. Avian influenza viruses are inactivated by heat and drying and also these viruses are very sensitive to most disinfectants and detergents. Avian influenza ai is an infectious disease of birds caused by type a strain of the influenza virus. A novel highly pathogenic avian influenza ah5n6 virus affecting wild birds and commercial poultry was detected in the netherlands in december 2017. The area to be disinfected must be clear of organic material, which greatly increases the resistance of avian influenza virus resistance to disinfection. General provisions 1 for the purposes of the terrestrial code, avian influenza is defined as an infection of poultry caused by any influenza a virus of the h5 or h7 subtypes or by any influenza a virus with an intravenous pathogenicity index. Dangerous beauty influenza virus ah1n1 the new influenza is a respiratory tract disease caused by influenza viruses of type ah1n1.
First, h5n1, though strictly an avian pathogen, has a documented ability to pass directly from birds to humans. Influenza in sweden 20162017 season this report describes the 20162017 influenza season, which was dominated by influenza ah3n2. For the purposes of transport, influenza virus isolates or influenza positive. Most infections with variant viruses have occurred in children persons 18 or younger and most cases have reported direct or indirect exposure to swine prior to onset of illness. Avian influenza is an economically important, highly contagious and fatal infectious disease of birds caused by type a strains of the influenza virus of orthomyxoviridae family. Its rapid spread to central asia, europe, the middle east, and africa in 2005 and 2006 caused legitimate concern throughout the entire world. Avian influenza viruses are classified as either low pathogenic also called low pathogenicity avian influenza viruses or highly pathogenic high pathogenicity avian influenza viruses. Avian influenza a virus h7n7 associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome. Information on avian influenza avian influenza flu.
Avian influenza virus influenza a virus is an orthomyxovirus. Since then, surveillance data from 2010 to 2014 revealed that 54% of 5643 herd tests involving 1567 pig herds and 28% of 23 036 blood samples screened positive for antibodies against influenza a virus. Postexposure antiviral chemoprophylaxis of close contacts of a patient with confirmed h7n9 virus infection andor high risk poultryenvironmental exposures. Ai is a highly contagious disease and some strains can cause high mortality in poultry. Influenza virus characterisation, july 2019 ecdc europa eu. Novel highly pathogenic avian influenza ah5n6 virus in the. Novel influenza a virus infections 20 case definition. Type b and c influenza viruses are not known to infect poultry or do not cause disease in. Avian influenza refers to the disease caused by infection with avian bird influenza flu type a viruses. Influenza virologic surveillance right size roadmap. Cdc recommends an annual seasonal flu vaccine to protect against seasonal influenza viruses.
In the late 1990s, a new strain of bird flu arose that was remarkable for its ability to cause severe disease and death, especially in domesticated birds such as ducks, chickens, or turkeys. Evidence for influenza virus cns invasion along the olfactory. The situation is different with infections of humans with avian influenza virus of the. The pandemic h1n109 virus is a swine origin influenza a virus subtype h1n1 virus strain that was responsible for the 2009 flu pandemic.
Furthermore, the viral genome responsible for human pandemic in the last century, either partially or entirely was originated from avian influenza viruses. A new influenza virus, discovered in pigs and later found in cows, shares common ancestry with known influenza viruses, but is distinct enough that researchers have proposed calling it type d. For other names, see the nomenclature section below. Variations of influenza a h3n2 virus in hong kong in 2014 winter. Avian influenza ai is an infectious disease of birds caused by type a strains of the influenza virus. Avian influenza virus h9n2 infections in farmed minks. Novel influenza a virus infections 2010 case definition. The current episode originated in southeast asia at least as far back as 1997.
Timeline of major events 25 january 2012 early events date events in animals events in humans 1996 highly pathogenic h5n1 virus is isolated from a farmed goose in guangdong province, china. Influenza a virus subtype h1n1 ah1n1 is the subtype of influenza a virus that was the most common cause of human influenza flu in 2009, and is associated with the 1918 outbreak known as the spanish flu. Seasonal influenza viruses circulate and cause disease in humans every year. Highly pathogenic avian influenza ah5n1 virus among.
Human infections have occurred, usually as isolated, rare, individual cases. Second, once in humans, h5n1 causes severe disease with very high mortality. Influenza, commonly known as the flu, is an infectious disease of birds and mammals. In collaboration with domestic and global partners, cdcs influenza division pdf icon1. The strong evidences suggested that h9n2 viruses had broken through species barriers and become capable of infecting various mammals, including humans 24. Update of the development and availability of candidate vaccine viruses for avian influenza ah7n9 pdf, 81kb 20 may 20. Novel highly pathogenic avian influenza ah5n6 viruses in. Update of who biosafety risk assessment and guidelines for the production and quality control of human influenza vaccines against avian influenza ah7n9 virus pdf, 609kb 10 may 20 updated on 23 may 20 development and distribution of. Cdc confirms two human infections with novel influenza. Types of influenza viruses cdc centers for disease control.
However, this possibility combined with the increasing resistance of the h5n1 ai virus to currently available antiviral treatment and lack of complete vaccination effectiveness make this a critical human health risk. This novel virus is a reassortant of the hpai h5n8 subtype virus with polymerase basic 2 pb2 and neuraminidase. Novel highly pathogenic avian influenza ah5n6 virus in. Avian influenza 3 and that will spread readily from person to person is unknown. Weekly number of influenza virus detections, with previous season numbers shown for comparison. Seroprevalence of highly pathogenic avian influenza h5n1 virus infection among humans in mainland china. However, some viruses have been found to infect humans. Oct 09, 2012 remember that the purpose of a virus is to hijack a host cell and make lots of copies of itself see our viral life cycle animation for more information. Three genera exist with this family that pertain to influenza viruses, influenzavirus a, influenzavirus b, and influenzavirus c, each of which contain a single species, or type.