Amino acid substitutions within or near the active site of the viral neuraminidase (NA) may affect influenza virus fitness. In influenza A(H3N2) and B viruses circulating in Thailand between 2010 and 2015, we identified several NA substitutions that were previously reported to be associated with reduced inhibition by NA inhibitors (NAIs). To study the effect of these substitutions on the enzyma...

Among the many kinds of respiratory infectious diseases caused by viruses, influenza is thought to be one of the most important factors affecting human social life. Since 1980, we have continued surveillance on influenza epidemiology among children in part of a thickly inhabited area of Tokyo Metropolis, around Kamata in Ota Ward. Influenza epidemics occurred every winter in this surveillance p...

The influenza virus hemagglutinin molecule possesses a globular head domain that mediates receptor binding and a stalk domain at the membrane-proximal region. We generated functional influenza viruses expressing chimeric hemagglutinins encompassing a variety of globular head and stalk combinations, not only from different hemagglutinin subtypes but also from different hemagglutinin phylogenetic...

Background and Aims: Influenza A virus of Orthomyxoviridae family is able to create pandemic influenza. Vaccination is the most effective way to prevent influenza virus infection. Matrix protein 2 (M2) is a homotetramer ion channel with 97 amino acids length and highly conserved among influenza viruses and is considered for development of a universal influenza vaccine. Materials and Methods: We...

BACKGROUND Although influenza virus resistance to the neuraminidase inhibitor zanamivir is reported less frequently than is resistance to the neuraminidase inhibitor oseltamivir in clinical settings, it is unknown whether this difference is due to the limited use of zanamivir or to an inherent property of the drug. We therefore compared the prevalence of drug-resistant viruses and virus sheddin...

Background and Aims: Influenza virus is a major pathogen involved in respiratory illnesses during winter seasons. A variety of diagnostic methods have been developed to identify influenza viruses in clinical specimen. Methods: Nasal and pharyngeal samples taken from patients were inoculated into Madin-Darby canine kidney (MOCK) cells and embryonated chicken eggs (ECEs). The culture media was a...

BACKGROUND The 2009 influenza A(H1N1) pandemic called attention to the limited influenza treatment options available, especially in individuals at high risk of severe disease. Neuraminidase inhibitor-resistant seasonal H1N1 viruses have demonstrated the ability to transmit well despite early data indicating that resistance reduces viral fitness. 2009 H1N1 pandemic viruses have sporadically appe...

The influenza virus PB1-F2 protein is a novel protein previously shown to be involved in induction of cell death. Here we characterize the expression and the function of the protein within the context of influenza viral infection in tissue culture and a mouse model. We show that the C-terminal region of the protein can be expressed from a downstream initiation codon and is capable of interactio...

Human influenza viruses attach to sialic acid with an alpha2,6linkage (SAalpha2,6Gal) on the airway epithelial cells, and the entry of the viruses into the cells and uncoating of the viruses require low pH of endosomes. Bafilomycin A(1), a macrolide antibiotic and a specific inhibitor of vacuolar H(+)-ATPase, inhibits growth of type A and type B human influenza viruses in Madin-Darby canine kid...

Avian influenza A viruses of the H7 subtype have resulted in more than 100 cases of human infection since 2002. Highly pathogenic avian influenza (HPAI) H7 viruses have the capacity to cause severe respiratory disease and even death; however, the induction of the human innate immune response to H7 virus infection has not been well characterized. To better understand H7 virus pathogenesis in the...