Sentence examples for major antigenic shift from inspiring English sources
The last major antigenic shift event was in 1968 and it generated the H3N2 (Hong Kong 'flu) strain that has been in circulation since.
A major antigenic shift resulting in a pandemic potential influenza virus is anticipated to cause a major threat to public health.
Major antigenic shift associated with genetic reassortment has led to devastating pandemics in 1918, 1957 and 1968, when pathogenic viruses with efficient human-to-human transmission entered the human population with no pre-existing immunity.
Influenza viruses are constantly changing either through the collection of minor point mutations or through major antigenic shifts.
Influenza A virus experiences two major antigenic changes, antigenic shift (gene reassortment) and antigenic drift (point mutation), whereas influenza B and C viruses undergo antigenic drift only.
Because vaccines have to be manufactured before the actual epidemic strains are known, a failure to anticipate emergence of a strain with major antigenic drift or shift relative to the vaccine will result in a substantial reduction or abrogation of vaccine-mediated protection.
Recombination involving major outer membrane antigen genes — "antigenic shift" has been linked to increased incidence of meningococcal disease (Harrison et al., 2006).
In addition, antigenically novel strains or subtypes of influenza A virus can emerge and spread rapidly due to a major antigenic change known as antigenic shift, causing global pandemics such as the ones that occurred in the last century or the recent H1N1 pandemic (pdmH1N1) in 2009 [ 13– 13].
The influenza virus is continually evolving and under immune pressure; it may either evolve through small gradual changes in the virus (antigenic drift) or through abrupt major changes in the virus (antigenic shift) most frequently by genetic reassortments [ 3].
Although the major antigenic variation results from the shift of expression from one opa gene to the next, antigenic differences between the Opa proteins can also arise through a variety of genetic events, for example point mutation, deletion, translocation and import from other members of the Neisseriaceae.
Ongoing, comprehensive surveillance is vital to addressing influenza because influenza A viruses have the capacity to undergo abrupt shifts in the major antigenic determinants of their surface proteins (4 ); these shifts can give rise to novel influenza viruses capable of producing catastrophic pandemics (5 ).
