Alexander I. Karasin

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Since 2003, three novel genotypes of H1 influenza viruses have been recovered from Canadian pigs, including a wholly human H1N2 virus and human-swine reassortants. These isolates demonstrate that human-lineage H1N2 viruses are infectious for pigs and that viruses with a human PB1/swine PA/swine PB2 polymerase complex can replicate in pigs.
Since 1998, H3N2 viruses have caused epizootics of respiratory disease in pigs throughout the major swine production regions of the U.S. These outbreaks are remarkable because swine influenza in North America had previously been caused almost exclusively by H1N1 viruses. We sequenced the full-length protein coding regions of all eight RNA segments from four(More)
Since January 2005, H3N2 influenza viruses have been isolated from pigs and turkeys throughout Canada and from a swine farmer and pigs on the same farm in Ontario. These are human/classical swine/avian reassortants similar to viruses that emerged in US pigs in 1998 but with a distinct human-lineage neuraminidase gene.
In October 1999, H4N6 influenza A viruses were isolated from pigs with pneumonia on a commercial swine farm in Canada. Phylogenetic analyses of the sequences of all eight viral RNA segments demonstrated that these are wholly avian influenza viruses of the North American lineage. To our knowledge, this is the first report of interspecies transmission of an(More)
An H1N2 influenza A virus was isolated from a pig in the United States for the first time in 1999 (A. I. Karasin, G. A. Anderson, and C. W. Olsen, J. Clin. Microbiol. 38:2453-2456, 2000). H1N2 viruses have been isolated subsequently from pigs in many states. Phylogenetic analyses of eight such viruses isolated from pigs in Indiana, Illinois, Minnesota,(More)
Avian lineage H4N6 influenza viruses previously isolated from pigs differ at hemagglutinin amino acids 226 and 228 from H4 subtype viruses isolated from birds. Using a parental H4N6 swine isolate and hemagglutinin mutant viruses (at residues 226 and/or 228), we determined that viruses which contain L226 had a higher affinity for sialic acid alpha2,6(More)
An H1N2 influenza virus was isolated from a pig during an outbreak of respiratory disease and abortion on an Indiana farm in November 1999. Results of phylogenetic analyses indicate that this virus is a reassortant between a recent classical H1 swine virus and the reassortant H3N2 viruses that have emerged among American pigs since 1998.
Influenza is a common respiratory disease in pigs, and since swine influenza viruses are zoonotic pathogens, they also pose human health risks. Pigs infected with influenza virus mount an effective immune response and are protected from subsequent challenge, whereas the currently available, inactivated-virus vaccine does not consistently confer complete(More)
 Influenza virus infection in pigs is both an animal health problem and a public health concern. As such, surveillance and characterization of influenza viruses in swine is important to the veterinary community and should be a part of human pandemic preparedness planning. Studies in 1976/1977 and 1988/1989 demonstrated that pigs in the U.S. were commonly(More)
To study the receptor specificities of H1 and H3 influenza viruses isolated recently from pigs, we employed the analogues of natural receptors, namely sialyloligosaccharides conjugated with polyacrylamide in biotinylated and label free forms. All Madin-Darby canine kidney (MDCK) cell-propagated viruses with human H3 or classical swine H1 hemagglutinins(More)