BACKGROUND Avian influenza A (H7N9) virus has emerged recently and continues to cause severe disease with a high mortality rate in humans prompting the development of candidate vaccine viruses. Live attenuated influenza vaccines (LAIV) are 6:2 reassortant viruses containing the HA and NA gene segments from wild type influenza viruses to induce protective immune responses and the six internal ge...

In the United States there are currently two influenza vaccine platforms approved for use in humans-conventional inactivated virus and live-attenuated influenza virus (LAIV). One of the major challenges for influenza A virus (IAV) vaccination is designing a platform that provides protection across strains. Pandemic H1N1 (pH1N1) IAV swept the globe in 2009 and crossed the species barrier, infect...

Title of Document: MOLECULAR MARKERS OF INTERSPECIES TRANSMISSION OF H2N2 AND H9N2 INFLUENZA A VIRUSES Erin Maureen Sorrell, Ph.D., 2008 Directed By: Associate Professor, Daniel R. Perez, Department of Veterinary Medicine Most avian influenza viruses do not replicate or transmit efficiently in mammals. The events that lead to interspecies transmission and host adaptation are unknown. Part one o...

The hemagglutinin (HA) genes of the influenza A H3N2 subtype viruses isolated from 1968 to 2010 have evolved substantially but their neuraminidase (NA) genes have been relatively less divergent. The H3N2 viruses isolated since 1995 were found to replicate in the lower respiratory tract of ferrets less efficiently than the earlier isolates. To evaluate whether the HA or/and NA or the internal pr...

Influenza A virus (IAV) can infect avian and mammalian species, including humans. The genome nature of IAVs may contribute to viral adaptation in different animal hosts, resulting in gene reassortment and the reproduction of variants with optimal fitness. As seen again in the 2009 swine-origin influenza A H1N1 pandemic, pigs are known to be susceptible to swine, avian, and human IAVs and can se...

In addition to influenza A subtypes, two distinct lineages of influenza B virus also cause seasonal epidemics to humans. Recently, Dudas et al. have done evolutionary analyses of reassortment patterns of the virus and suggested genetic lineage relationship between PB1, PB2, and HA genes. Using genetic plasmids and reassortant viruses, we here demonstrate that a homologous lineage PB1-PB2 pair e...

On 31 March 2013, Chinese authorities announced the identification of a novel reassortant A(H7N9) influenza virus isolated from three unlinked cases of severe respiratory disease in eastern China; two in Shanghai and one in Anhui province. The type A influenza viruses initially isolated from the three cases could not be subtyped and had therefore been sent to the WHO Collaborating Centre for Re...

Reassortment between different species or strains plays a key role in the evolution of multipartite plant viruses and can have important epidemiological implications. Identifying geographic locations where reassortant lineages are most likely to emerge could be a valuable strategy for informing disease management and surveillance efforts. We developed a predictive framework to identify potentia...

Bovine rotavirus NCDV and simian rotavirus SA-11 exhibited markedly different patterns of gastrointestinal tract disease when inoculated orally into newborn mice. A genetic approach was used to define the molecular basis of these differences. The SA-11 strain of rotavirus was more virulent than the NCDV strain when inoculated orally into newborn mice; the dose of SA-11 required to cause diarrhe...

Here, we report the complete genomic sequence of a novel reassortant H4N2 influenza virus isolated from domestic ducks in the Jiangsu province of China in 2011. Phylogenetic analysis showed that all the viral genes except for hemagglutinin (HA) were highly homologous to the clade 2.3.4 H5N2 viruses. The data suggest that genetic reassortment occurred between H4 and H5N2 avian influenza viruses,...