The influenza virus has had a good track record for crossing from birds to humans (avian flu) and from pigs to humans (swine flu) the influenza virus has eight different components to its makeup, which allows for many different combinations of viruses that include swine, avian, and human flu. There are three influenza viruses groups, a, b and c, which are portion of the orthomyxoviridae household of ( - ) strand rna viruses these viruses are segmented incorporating 8 separate cistron sections within a nucleocapsid protein ( neumann, g et al 2009 ). What is the biology of influenza virus antigenic drift and occasional antigenic shift section a antigenic variation in influenza virus: i i antigenic drift.
Antigenic shift causes sudden, unexplained changes to the virus antigenic drift causes minor point mutations, with small change to the virus the virus enters the host by evading the immune system. Antigenic shift from reassortment can produce major changes in the influenza virus and represents a significant way for viruses to evolve and create a new pandemic strain influenza's genome is made up of eight loosely linked segments, each of which harbors at least one important gene. Antigenic shift is contrasted with antigenic drift, which is the natural mutation over time of known strains of influenza (or other things, in a more general sense) which may lead to a loss of immunity, or in vaccine mismatch antigenic drift occurs in all types of influenza including influenza a, b and c antigenic shift, however, occurs only.
Antigenic shift is contrasted with antigenic drift, which is the natural mutation over time of known strains of influenza (or other things, in a more general sense) which may lead to a loss of immunity, or in vaccine mismatch. A gradual minor point mutation in the genes responsible for encoding ha and na proteins on the surface of the influenza virus, called antigenic drift, may occur antigenic shift may occur as well. Differences between antigenic shift and antigenic drift june 23, 2018 october 13, 2015 by sagar aryal influenza virus are remarkable because of the frequent antigenic change that occurs in ha (hemagglutinin) or na (neuraminidase.
This hands-on activity is a powerful tool in teaching the concepts of antigenic drift and shift an good understanding these concepts is vital to enable students to understand variation due to natural selection. This lecture explains about the mechanism of the antigenic shift and drift to produce influenza virus with antigenic variation antigenic drift is a small change in gene sequence but antigenic. Define antigenic shift and antigenic drift and explain their importance in causing epidemics or pandemics of influenza one is called antigenic drift these are small changes in the virus that happen continually over time. Analysis of the influenza virus biology essay influenza is an infective diseases caused by influenza virus that cause seasonal epidemics of respiratory infection this infection sometimes can be life endangering.
However, such protection is not effective against newly emerging influenza viruses that contain antigenic variations known as antigenic drift and shift antigenic drift refers to a minor change (such as amino acid substitution in ha and/or na) resulting in antigenic site change. Mutations-antigenic shift and drift in influenza a viruses influenza viruses evolve and mutate according to two mechanisms: mutations (antigenic or antigen slides) or antigenic reassortment. Evolution of influenza where changes cause mild and limited epidemics ii because these changes are small (usually arise from point mutations) there will still be come cross-reaction with antibodies and t cells produced to the previous variant- provides some level of protection. Influenza a is a highly contagious virus, which can cause dramatic illness, periodic pandemics and outbreaks globally every year the major source of these onsets per annum is the emergence of an antigenically novel virus which the human population lack protective immunity against.
Non-human influenza viruses belong to type a whereas human influenza viruses belong to type a, b and c non-human viruses do not infect man but play an important role in the emergence of pandemic influenza by genetic re-assortment with human viruses. Antigenic drift refers to small, gradual changes that occur through point mutations in the two genes that contain the genetic material to produce the main surface proteins of the influenza virus, hemagglutinin (h), and neuraminidase (n), (how influenza viruses change, 2005. Barr ig, et al who recommendations for the viruses used in the 2013-2014 northern hemisphere influenza vaccine: epidemiology, antigenic and genetic characteristics of influenza a(h1n1)pdm09, a(h3n2) and b influenza viruses collected from october 2012 to january 2013.