"Antigenic and genetic characteristics of H5N1 viruses and candidate H5N1 vaccine viruses developed for potential use as pre-pandemic vaccines" (PDF). The NS1 gene of the highly pathogenic avian H5N1 viruses circulating in poultry and waterfowl in Southeast Asia is believed to be responsible for an enhanced proinflammatory cytokine response (especially TNFa) induced by these viruses in human macrophages. and/or as an "WikiHow" type article referenced wherever relevant within Wikipedia. | [38] Few persons over 50 years of age seem to have become infected by H5N1, and very few have died after suffering an H5N1 attack. Report of a WHO working group The testing and reporting necessary for mass serology studies to determine the incidence of overlooked cases for each existing clade and strain of H5N1 worldwide would be prohibitively costly. MAJOR ARTICLE Rather than die-offs of large numbers of waterfowl during winter when they congregate, small numbers (mainly singleton birds) were affected late in winter, just before spring migration. In most cases, this testing failed to turn up any overlooked mild cases, though in at least one study mild overlooked cases were identified. If over 20% of the unreported 70% of cases are persons who did NOT die, then the overall Indonesian lethality rate is lower than the reported 80% for the reported cases. A strain of influenza becomes a pandemic because the population is naive to it and lacks immunity. In 2005, when a markedly less-lethal strain in Northern Vietnam was responsible for most of the cases reported worldwide, only 42 of 97 people confirmed by the WHO to be infected with H5N1 died — a 43% fatality rate. There "is evidence of at least three independent virulence factors connected with three different genes. They were developed based on N2 and N9. [14] This strain was "highly pathogenic" (deadly to birds) but caused neither illness nor death in humans. The change was nonetheless interpreted by some as indicating that the virus itself was becoming more deadly over time. As shown below, the mechanisms by which a "Z" pandemic would have to evolve may be the slower processes of recombination or mutation, rather than the quicker reassortment. Recent studies have shown that in the immuno-naive group -- young children -- FluMist was markedly more effective at reducing influenza infection. [67] One such report stated that "over half a million Americans could die and over 2.3 million could be hospitalized if a moderately severe strain of a pandemic flu virus hits the U.S.". google_ad_width = 728;
While the real H5N1 CF rate (what it would be if we had perfect knowledge) could be lower (one study suggests that the real H5N1 CF rate is closer to 14–33%); it is unlikely that, if it becomes a pandemic, it will go to the 0.1–0.4% level currently embraced by many pandemic plans. Another factor that grows potentially more important with the passage of time is human preparation. They were developed based on N2 and N9. "Are the conclusions of this one study enough to warrant rethinking the current bird-flu paradigm and considering this threat similar to that posed by the similar "Asian Flu," as opposed to the deadly "Spanish Flu" pandemic? "HHS has enough H5N1 vaccine for 4 million people". Ensimmäinen tapaus, jossa H5N1:n todettiin tarttuneen EU:n alueella siipikarjaan, raportoitiin 23. helmikuuta 2006 itäranskalaisesta kalkkunatarhasta, jonka alueella oli aiemmin todettu kahdessa kuolleessa sorsassa H5N1-virusta.Tapauksen johdosta Japani on kieltänyt siipikarjan lihan tuonnin Japaniin ja on uhannut laajentaa kieltoaan myös hollantilaisiin tuotteisiin. The PB1-F2 protein probably contributes to viral pathogenicity and might have an important role in determining the severity of pandemic influenza. | On May 30, Maria Cheng, a WHO spokeswoman, said there were "probably about half a dozen," but that no one "has got a solid number. [2]. Conservative estimates suggest that up to 350 million people could die and many more would be affected, causing disruption to health-care systems, society, and the world's economy. There is no basis for assuming that an H5N1 pandemic will emerge with only the far lower 1-2% lethality rate of the Spanish Flu, once assumed to be a worst case scenario. Avian influenza virus (H5N1): a threat to human health. Scientists are very concerned about what we do know about H5N1; but even more concerned about the vast amount of important data that we don't know about H5N1 and its future mutations. . The fatality ratio for H5N1 infections would then be calculated as the same number of deaths, but divided by a doubled number for total cases, resulting in a hypothetical death ratio of half the currently reported fatality ratio. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website. It is more probable that evolutionary adaptation of the haemagglutinin of H5N1 viruses to the human-type receptor will happen without any simultaneous change in those other genetic properties that now are important for explaining the exceptionally high virulence of certain strains of avian-adapted H5N1 influenza virus. Either way it's a big number. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. Unconfirmed cases have a potentially huge impact on the case fatality ratio. Human mortality from avian influenza to date is around 60%. Examination of the reconstructed lethal Spanish Flu virus shows it was a predominantly avian virus that had made only the relatively few molecular changes necessary to infect humans, analogous to the changes that the H5N1 virus now appears to be undergoing. For example, no influenza vaccine specific to H5N1 could be produced when it emerged in Hong Kong in 1997, because it was lethal to eggs. Likewise, annual flu vaccination includes inoculation against a type-A human H1N1 flu, leading to the possibility that the annual flu shot or Flumist inoculation might confer some immunity against H5N1 bird flu infection, and indeed testing the blood of volunteers to look for immune response to H5N1 found that some blood samples showed immunity, but more of the blood samples of persons who had received the flu shot showed an immune response.[40]. On May 30, Maria Cheng, a WHO spokeswoman, said there were "probably about half a dozen," but that no one "has got a solid number. H5N1 flu is a concern due to the global spread of H5N1 that constitutes a pandemic threat. Recently, some 75% of H5N1 human virus isolates identified in Vietnam had a mutation consisting of Lysine at residue 627 in the PB2 protein; a change believed associated with high levels of virulence. If a human pandemic does not emerge in the next few years, its eventual emergence may become almost a non-event if a very-effective pre-pandemic vaccine has prepared the population with sufficient herd immunity to blunt its lethality. [15] In 1997, in Hong Kong, 18 humans were infected and 6 died in the first known case of H5N1 infecting humans. ), detailed shape and gene code analysis of each of the RNA strands for as many flu virus strains as possible and making them available on a database for study, testing humans for asymptomatic H5N1 infection. [19]-- or 69%. With an accout for my.bionity.com you can always see everything at a glance – and you can configure your own website and individual newsletter. Sexual Content
The H5N1 virus can cause severe flu with a high mortality rate. Since Indonesia stopped sending samples to the WHO in February, 2007, and the WHO stopped including Indonesian cases in its case and fatality reports, the majority of cases have been from Egypt, where a much milder form of bird flu seems to be circulating, infecting many but killing only a minority. An additional factor which may be active is that H1N1 was the predominate human flu circulating until about 1957 or 1958. Virus surveillance in both countries includes both active cloacal swabbing of free-ranging wild birds and passive collection of tracheal swabs from bird carcasses. Whether the H5N1 genes coding for lethality in humans are included in a reassortment or not is almost a matter of indifference to the emergence of the original pandemic strain. Scientific advances may attenuate probable lethality. Although the actual rate of mortality during a pandemic is unknowable in advance, it is pressing to predict the possible ranges for that lethality responsibly in advance. It suggests time to transmissibility may be higher than with reassortment, but the result may be deadlier. Jennings LC, Monto AS, Chan PK, Szucs TD, Nicholson KG (October 2008). [3] No pandemic strain of H5N1 has yet been found.