The term avian osteopetrosis is used to describe alterations to the skeletal elements of several species of domestic bird, most typically the chicken, Gallus gallus domesticus (L. 1758). Such lesions are routinely identified in animal bones from archaeological sites due to their distinctive appearance, which is characterised by proliferative diaphyseal thickening. These lesions are relatively u...

BACKGROUND Avian influenza viruses have caused human infection and posed the pandemic potential. Live poultry markets are considered as a source of human infection with avian influenza viruses. Avian influenza routine surveillance of live poultry markets is taken annually in China. We isolated the 2 H11N9 influenza virus from the surveillance program. To better understand the risk caused by the...

Avian influenza A viruses generally do not replicate efficiently in human cells, but substitution of glutamic acid (Glu, E) for lysine (Lys, K) at residue 627 of avian influenza virus polymerase basic protein 2 (PB2) can serve to overcome host restriction and facilitate human infectivity. Although PB2 residue 627 is regarded as a species-specific signature of influenza A viruses, host restricti...

BACKGROUND Highly pathogenic avian H5N1 influenza viruses preferentially infect alveolar type II pneumocytes in human lung. However, it is unknown whether this cellular tropism contributes to high viral virulence because the primary target cells of other influenza viruses have not been systematically studied. METHODS We provide the first comparison of the replication, tropism, and cytokine in...

The rapid outbreak of the highly pathogenic A/H5N1 avian influenza virus among domestic birds and its transmission to humans have induced world-wide fears of a new influenza pandemic. If a human-trophic strain of A/H5N1 is replicated in domestic animals, it might have high transmissivity and pathogenicity to humans. If the misassembling of both avian and swine influenza viruses occur in the sam...

Three pandemic influenza strains occurred in the 20 century, in 1918, 1957 and 1968. Influenza pandemic strains are the result of an emerging virus spreading in people which have little or non immunity. At least two of these pandemics strains, in 1957 and in 1968, were the result of reassortments between human and avian viruses. In 1957 three segments, PB1, HA and NA, and in 1968 two segments, ...

The segmented structure of the influenza virus genome plays a pivotal role in its adaptation to new hosts and the emergence of pandemics. Despite concerns about the pandemic threat posed by highly pathogenic avian influenza H5N1 viruses, little is known about the biological properties of H5N1 viruses that may emerge following reassortment with contemporary human influenza viruses. In this study...

H2N2 influenza A viruses were the cause of the 1957-1958 pandemic. Historical evidence demonstrates they arose from avian virus ancestors, and while the H2N2 subtype has disappeared from humans, it persists in wild and domestic birds. Reemergence of H2N2 in humans is a significant threat due to the absence of humoral immunity in individuals under the age of 50. Thus, examination of these viruse...

Avian influenza A viruses (IAVs) and human 1918, 1957, and 1968 pandemic IAVs all have neuraminidases (NAs) that are stable at low pH sialidase activity, yet most human epidemic IAVs do not. We examined the pH stability of H5N1 highly pathogenic avian IAV (HPAI) NAs and identified amino acids responsible for conferring stability at low pH. We found that, unlike other avian viruses, most H5N1 IA...

We isolated an avian influenza virus H9N2 strain from a wild bird in the Guangxi Province of southern China in 2013 named A/turtledove/Guangxi/49B6/2013(H9N2) (GX49B6). We aimed to understand the genetic characters of the GX49B6 strain by analyzing the complete genome sequence. The results showed that our isolated strain has features of low pathogenic avian influenza viruses and viruses that in...