Receptor characterization and susceptibility of cotton rats to avian and 2009 pandemic influenza virus strains.

Animal influenza viruses (AIVs) are a major threat to human health and the source of pandemic influenza. A reliable small-mammal model to study the pathogenesis of infection and for testing vaccines and therapeutics against multiple strains of influenza virus is highly desirable. We show that cotton rats (Sigmodon hispidus) are susceptible to avian and swine influenza viruses.

Fitness of Pandemic H1N1 and Seasonal influenza A viruses during Co-infection: Evidence of competitive advantage of pandemic H1N1 influenza versus seasonal influenza.

On June 11, 2009 the World Health Organization (WHO) declared a new H1N1 influenza pandemic. This pandemic strain is as transmissible as seasonal H1N1 and H3N2 influenza A viruses. Major concerns facing this pandemic are whether the new virus will replace, co-circulate and/or reassort with seasonal H1N1 and/or H3N2 human strains.

Partial direct contact transmission in ferrets of a mallard H7N3 influenza virus with typical avian-like receptor specificity.

Background: Avian influenza viruses of the H7 subtype have caused multiple outbreaks in domestic poultry and represent a significant threat to public health due to their propensity to occasionally transmit directly from birds to humans. In order to better understand the cross species transmission potential of H7 viruses in nature, we performed biological and molecular characterizations of an H7N3 virus isolated from mallards in Canada in 2001.

Results: Sequence analysis that the HA gene of the mallard H7N3 virus shares 97% identity with the highly pathogenic avian influenza (HPAI) H7N3 virus isolated from a human case in British Columbia, Canada in 2004.

Minimal molecular constraints for respiratory droplet transmission of an avian-human H9N2 influenza A virus.

Pandemic influenza requires interspecies transmission of an influenza virus with a novel hemagglutinin (HA) subtytpe that can adapt to its new host through either reassortment or point mutations and transmit by aerosolized respiratory droplets. Two previous pandemics of 1957 and 1968 resulted from the reassortment of low pathogenic avian viruses and human subtypes of that period; however, conditions leading to a pandemic virus are still poorly understood. Given the endemic situation of avian H9N2 influenza with human-like receptor specificity in Eurasia and its occasional transmission to humans and pigs, we wanted to determine whether an avian-human H9N2 reassortant could gain respiratory transmission in a mammalian animal model, the ferret.

An avian live attenuated master backbone for potential use in epidemic and pandemic influenza vaccines.

The unprecedented emergence in Asia of multiple avian influenza virus (AIV) subtypes with a broad host range poses a major challenge in the design of vaccination strategies that are both effective and available in a timely manner. The present study focused on the protective effects of a genetically modified AIV as a source for the preparation of vaccines for epidemic and pandemic influenza. It has previously been demonstrated that a live attenuated AIV based on the internal backbone of influenza A/Guinea fowl/Hong Kong/WF10/99 (H9N2), called WF10att, is effective at protecting poultry species against low- and high-pathogenicity influenza strains.