• proteins
  • Tree balance will be affected by selection, most notably immune escape (see figure 3) The effect of directional selection on the shape of a viral phylogeny is exemplified by contrasting the trees of influenza virus and HIV's surface proteins. (wikipedia.org)
  • This attachment is required for efficient transfer of flu virus genes into cells, a process that can be blocked by antibodies that bind to the hemagglutinin proteins. (wikipedia.org)
  • Influenza type A viruses are categorized into subtypes based on the type of two proteins on the surface of the viral envelope: H = hemagglutinin, a protein that causes red blood cells to agglutinate. (wikipedia.org)
  • viral
  • H3N2 is a subtype of the viral genus Influenzavirus A, which is an important cause of human influenza. (wikipedia.org)
  • Although viruses can differ with respect to many phenotypes, phylodynamic studies have to date tended to focus on a limited number of viral phenotypes. (wikipedia.org)
  • The relative lengths of internal versus external branches will be affected by changes in viral population size over time (see figure 1) Rapid expansion of a virus in a population will be reflected by a "star-like" tree, in which external branches are long relative to internal branches. (wikipedia.org)
  • Compared to a phylogeny of an expanding virus, a phylogeny of a viral population that stays constant in size will have external branches that are shorter relative to branches on the interior of the tree. (wikipedia.org)
  • The phylogeny of hepatitis B virus (caricatured by figure 1B) instead reflects a viral population that has remained roughly constant in size. (wikipedia.org)
  • The clustering of taxa on a viral phylogeny will be affected by host population structure (see figure 2) Viruses within similar hosts, such as hosts that reside in the same geographic region, are expected to be more closely related genetically if transmission occurs more commonly between them. (wikipedia.org)
  • PB1-F2 likely contributes to viral pathogenicity and might have an important role in determining the severity of pandemic influenza. (wikipedia.org)
  • infection
  • At least 12 companies and 17 governments are developing prepandemic influenza vaccines in 28 different clinical trials that, if successful, could turn a deadly pandemic infection into a nondeadly one. (wikipedia.org)
  • Swine influenza is an infection caused by any one of several types of swine influenza viruses. (wikipedia.org)
  • Persons who cough or sneeze should cover their mouths People should avoid touching their eyes, nose, or mouth, as these are routes of germ transmission Influenza A virus subtype H3N2 infections have predominated in China, which since November has reported low levels of flu infection Europe reported low but increasing levels of flu infection in the first week of 2013. (wikipedia.org)
  • Influenza B virus is almost exclusively a human pathogen, and is less common than influenza A. The only other animal known to be susceptible to influenza B infection is the seal. (wikipedia.org)
  • When they identified FI6, they injected it into mice and ferrets and found that it protected the animals against infection by either a Group 1 or Group 2 influenza A virus. (wikipedia.org)
  • From one donor, they isolated four plasma cells that produced an identical antibody, which they called FI6.This antibody binds all 16 HA subtypes, neutralizes infection, and protects mice and ferrets from lethal infection. (wikipedia.org)
  • antiviral drugs
  • 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)
  • But, because the replication of the influenza virus is somewhat error-prone, the virus evolves as a quasispecies, and widespread use of antiviral drugs can lead to resistant strains. (wikipedia.org)
  • 1957
  • From October 2004 to February 2005, approximately 3,700 test kits of the 1957 H2N2 virus were accidentally spread around the world from the College of American Pathologists (CAP). (wikipedia.org)
  • private contractor Meridian Bioscience in Cincinnati, U.S., chose the 1957 strand instead of one of the less deadly avian influenza virus subtypes. (wikipedia.org)
  • The 1957 H2N2 virus is considered deadly and the U.S. government called for the vials containing the strain to be destroyed. (wikipedia.org)
  • Phylogenetic
  • In a phylogenetic-based taxonomy, the category "RNA virus" includes the category "negative-sense ssRNA virus", which includes the Order "Mononegavirales", and the Family "Orthomyxovirus" (among others). (wikipedia.org)
  • vaccines
  • 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)
  • Of the 97 recent H3N2 isolates examined, only 41 had strong serologic cross-reactions with antiserum to three commercial SIV vaccines. (wikipedia.org)