The receptor specificity and cleavability of the hemagglutinin (HA) protein have been shown to regulate influenza A virus transmissibility and pathogenicity, but little is known about how its pH of activation contributes to these important biological properties. To identify amino acid residues that regulate the acid stability of the HA protein of H5N1 influenza viruses, we performed a mutationa...

BACKGROUND Identifying risk factors for zoonotic influenza transmission may aid public health officials in pandemic influenza planning. OBJECTIVES We sought to evaluate rural Iowan agriculture workers exposed to poultry for previous evidence of avian influenza virus infection. METHODS In 2004 we enrolled 803 rural adult Iowans in a 2-year prospective study of zoonotic influenza transmission...

With the exception of the live attenuated influenza vaccine there have been no substantial changes in influenza vaccine strategies since the 1940's. Here we report an alternative vaccine approach that uses Adenovirus-vectored centralized hemagglutinin (HA) genes as vaccine antigens. Consensus H1-Con, H3-Con and H5-Con HA genes were computationally derived. Mice were immunized with Ad vaccines e...

Infection of poultry with highly pathogenic avian influenza virus (AIV) can be devastating in terms of flock morbidity and mortality, economic loss, and social disruption. The causative agent is confined to certain isolates of influenza A virus subtypes H5 and H7. Due to the potential of direct transfer of avian influenza to humans, continued research into rapid diagnostic tests for influenza i...

Highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 not only cause a devastating disease in domestic chickens and turkeys but also pose a continuous threat to public health. In some countries, H5N1 viruses continue to circulate and evolve into new clades and subclades. The rapid evolution of these viruses represents a problem for virus diagnosis and control. In this work, recombin...

Abstract H5N1 vaccines adjuvanted in the oil-in-water emulsion MF59 are maintained Strategic National Stockpile for pre-pandemic preparedness. The US population currently naïve to H5 and a prime/boost regimen will likely be needed engender protective response. Ideally, rapid response pandemic influenza would benefit from being able induce protection single dose of vaccine. Here, we have used sy...

Recently, three novel avian-origin swine influenza viruses (SIVs) were first isolated from pigs in Guangdong Province, southern China, yet little is known about the seroprevalence of avian influenza viruses among pigs in southern China. Here, we report for the first time the seroprevalence of avian H3, H4, and H6 influenza viruses in swine populations and the lack of seroepidemiological evidenc...

The emergence of highly pathogenic (HP) H5 influenza A viruses in Asia and the increase of HP H7 viruses in Europe and the Americas focused greater attention on the ecology of influenza in wild birds. Influenza virus surveillance studies in wild bird populations in the Americas, Europe, and Asia confirmed that wild aquatic birds are the reservoir for all known influenza A viruses. Phylogenetic ...

The first documented outbreak of human respiratory disease caused by avian influenza A (H5N1) viruses occurred in Hong Kong in 1997. The kinetics of the antibody response to the avian virus in H5N1-infected persons was similar to that of a primary response to human influenza A viruses; serum neutralizing antibody was detected, in general, >/=14 days after symptom onset. Cohort studies were cond...

Here, we report the diversity of amantadine-resistant mutants among avian influenza A viruses with pandemic potential (H5, H6, H7, and H9 hemagglutinin subtypes). Drug-resistant variants were not detected among 1979--83 isolates, whereas 31.1% of H5 and 10.6% of H9 strains from Southeast Asia isolated in 2000-04 carried mutations in M2 protein. In North America, resistant variants occurred amon...