The adaptive evolution of the hemagglutinin (HA) segment of the human influenza H1N1 and H3N2 viruses is not well understood due to antigenic mutations under selection pressures. This paper identified significant antigenic selection sites and discussed the structural relevance of these mutations. We discovered four positively selected sites for H1N1 (position 206 for the 1A lineage - 2009 swine...

Avian influenza virus (H5N1) can be transmitted to humans, resulting in a severe or fatal disease. The aim of this study was to evaluate the immune cross-reactivity between human and avian influenza (H5N1) strains in healthy donors vaccinated for seasonal influenza A (H1N1)/(H3N2). A small frequency of CD4 T cells specific for subtype H5N1 was detected in several persons at baseline, and season...

Although raccoons (Procyon lotor) are susceptible to influenza viruses, highly pathogenic avian influenza virus (H5N1) infection in these animals has not been reported. We performed a serosurvey of apparently healthy feral raccoons in Japan and found specific antibodies to subtype H5N1 viruses. Feral raccoons may pose a risk to farms and public health.

A strain of swine influenza has been observed to change from a condition of full contagiousness, in which both H. influenzae suis and the swine influenza virus were transferred by pen contact, to one of only partial contagiousness, in which the virus alone was transferred, resulting in the mild filtrate disease instead of swine influenza in animals infected by contact. Swine that had been exper...

Avian influenza or "bird flu" is causing increasing concern across the world as experts prepare for the possible occurrence of the next human influenza pandemic. Only influenza A has ever been shown to have the capacity to cause pandemics. Currently A/H5N1, a highly pathogenic avian influenza virus, is of particular concern. Outbreaks of this disease in birds, especially domestic poultry, have ...

BACKGROUND In 2008, 800 rural Thai adults living within Kamphaeng Phet Province were enrolled in a prospective cohort study of zoonotic influenza transmission. Serological analyses of enrollment sera suggested this cohort had experienced subclinical avian influenza virus (AIV) infections with H9N2 and H5N1 viruses. METHODS After enrollment, participants were contacted weekly for 24 mos for ac...

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 as...

influenza is an acute respiratory disease caused by the influenza a or b virus. it often occurs in outbreaks and epidemics worldwide, mainly during the winter season. significant numbers of influenza virus particles are present in the respiratory secretions of infected persons, so infection can be transmitted by sneezing and coughing via large particle droplets. the mean duration of influenza v...