Dating the emergence of pandemic influenza
TY - JOURT1 - Dating the emergence of pandemic influenza viruses AU - Smith, Gavin J. AU - Bahl, Justin AU - Vijaykrishna, Dhanasekaran AU - Zhang, Jinxia AU - Poon, Leo L. Despite global concern regarding a new pandemic influenza, the emergence pathway of pandemic strains remains unknown.
Furthermore, seasonal and classic swine H1N1 viruses were not derived directly from BM/1918, but their precursors co-circulated during the pandemic.
Mean estimates of the time of most recent common ancestor also suggest that the H2N2 and H3N2 pandemic strains may have been generated through reassortment events in unknown mammalian hosts and involved multiple avian viruses preceding pandemic recognition.
The possible generation of pandemic strains through a series of reassortment events in mammals over a period of years before pandemic recognition suggests that appropriate surveillance strategies for detection of precursor viruses may abort future pandemics.
Phylogenetic relationships suggest that the A/Brevig Mission/1/1918 virus (BM/1918) was generated by reassortment between mammalian viruses and a previously circulating human strain, either in swine or, possibly, in humans.
Furthermore, seasonal and classic swine H1N1 viruses were not derived directly from BM/1918, but their precursors co-circulated during the pandemic. Malik AU - Guan, Yi PY - 2009/7/14Y1 - 2009/7/14N2 - Pandemic influenza viruses cause significant mortality in humans.
Three worldwide (pandemic) influenza outbreaks occurred in the last century.
Each differed from the others with respect to etiologic agents, epidemiology, and disease severity. In the case of the 2 that occurred within the era of modern virology (19), the hemagglutinin (HA) antigen of the causative viruses showed major changes from the corresponding antigens of immediately antecedent strains.
Our results indicate that genetic components of the 1918 H1N1 pandemic virus circulated in mammalian hosts, i.e., swine and humans, as early as 1911 and was not likely to be a recently introduced avian virus.Again, please keep their identity a secret Click on the "Continue" button search with your zip/postal code.Three worldwide (pandemic) outbreaks of influenza occurred in the 20th century: in 1918, 1957, and 1968.These pandemics were initiated by the introduction and successful adaptation of a novel hemagglutinin subtype to humans from an animal source, resulting in antigenic shift.Despite global concern regarding a new pandemic influenza, the emergence pathway of pandemic strains remains unknown.
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Major influenza epidemics show no predictable periodicity or pattern, and all differ from one another.