A dramatic increase in the frequency of the H275Y mutation in the neuraminidase (NA), conferring resistance to oseltamivir, has been detected in human seasonal influenza A/H1N1 viruses since the influenza season of 2007-2008. The resistant viruses emerged in the ratio of 14.3% and quickly reached 100% in Taiwan from September to December 2008. To explore the mechanisms responsible for emergence...

An avian influenza virus strain, A/domestic green-winged teal/Hunan/3450/2006(H5N1) (DGW-T3450), was isolated from domestic green-winged teals. Genome analysis demonstrated that DGW-T3450 is a novel reassortant strain. The hemagglutinin (HA) and neuraminidase (NA) genes of this strain originated from H5N1 viruses circulating in poultry, while its remaining genes are derived from multiple ancest...

During two winter seasons between 1999 and 2001, seven strains of influenza virus were isolated from healthy pigs in Saitama Prefecture, Japan. All isolates were identified as A (H1N2) reassortant viruses. Genetic and phylogenetic analyses indicated that they had classical swine-like hemagglutinin (HA) and internal genes, and relatively early human-like neuraminidase (NA) gene. The HA and NA ge...

In 2007, an H3N2 influenza A virus was isolated from Canadian mink. This virus was found to be phylogenetically related to a triple reassortant influenza virus which emerged in Canadian swine in 2005, but it is antigenically distinct. The transmission of the virus from swine to mink seems to have occurred following the feeding of animals with a ration composed of uncooked meat by-products of sw...

The objective of this study was to characterize the off-seasonal influenza virus A subtype H3N2, which caused an outbreak in an elderly hospital in Niigata, Japan. Virus isolates were subtyped by the hemagglutination-inhibition test and screened for antiviral drug sensitivity by real-time PCR using cycling probe technology the and 50% inhibitory concentration (IC(50)) method. Whole genome seque...

Aedes triseriatus mosquitoes were orally infected with two different California serogroup bunyaviruses (La Crosse and snowshoe hare viruses) and high frequency reassortment occurred in these mosquitoes. Increased viral replication and subsequent gene segment reassortment was noted in the ovaries of mosquitoes that had ingested multiple blood-meals. To determine whether newly generated reassorta...

Co-infection with seasonal influenza A (H1N1) and pandemic (H1N1) 2009 could result in reassortant viruses that may acquire new characteristics of transmission, virulence, and oseltamivir susceptibility. Results from oseltamivir-sensitivity testing on viral culture suggested the possibility of co-infections with oseltamivir-resistant (seasonal A [H1N1]) and -susceptible (pandemic [H1N1] 2009) v...

H3 subtype avian influenza virus (AIV) poses a great threat to public health, and so investigating its epidemiology is of great importance. A novel reassortant H3N2 AIV strain was isolated from a live poultry market in eastern China. The strain's genes originated from H1N1, H3, and H7 AIVs. Thus, the genome information of the H3N2 isolate will help to investigate further the epidemiology of H3 ...