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, ...

H1N1 influenza A viruses isolated from pigs in Europe since 1981 were examined both antigenically and genetically and compared with H1N1 viruses from other sources. H1N1 viruses from pigs and birds could be divided into three groups: avian, classical swine and 'avian-like' swine viruses. Low or no reactivity of 'avian-like' swine viruses in HI tests with monoclonal antibodies raised against cla...

Seropositivity to avian influenza (AI) via low-level antibody titers has been reported in the general population and poultry-exposed individuals, raising the question whether these findings reflect true infection with AI or cross-reactivity. Here we investigated serological profiles against human and avian influenza viruses in the general population using a protein microarray platform. We hypot...

BACKGROUND Wild waterfowl are considered as the natural reservoir for avian influenza (AI) viruses. Bangladesh has been experiencing highly pathogenic avian influenza (HPAI) outbreaks since 2007, mostly in chickens and occasionally in ducks. Ducks play an important role in the persistence and genetic recombination of AI viruses. This paper presents the results of serological and virological mon...

Following the initial and sporadic emergence into humans of highly pathogenic avian H5N1 influenza A viruses in Hong Kong in 1997, we have come to realize the potential for avian influenza A viruses to be transmitted directly from birds to humans. Understanding the basic viral and cellular mechanisms that contribute to infection of mammalian species with avian influenza viruses is essential for...

objectives the aim of this was to indentify the presence of a/h9n2 virus among different high risk occupational groups, in tehran and qazvin provinces in seasonal outbreak in iran. background in the last decade h9n2 avian influenza viruses had caused outbreaks in poultry in many parts of the world. this subtype could infect other animals such as human and pig. avian h9n2 virus has acquired rece...

Human influenza pandemics have historically been caused by reassortant influenza A viruses using genes from human and avian viruses. This genetic reassortment between human and avian viruses has been known to occur in swine during viral circulation, as swine are capable of circulating both avian and human viruses. Therefore, avian-to-swine transmission of viruses plays an important role in the ...

Reassortment among the RNA segments of Influenza A virus caused the two most recent human influenza pandemics; recently, reassortment has generated viral genotypes associated with outbreaks of avian H5N1 influenza in Asia and Europe. A statistical analysis has been developed for the systematic identification and characterization of reassortant viruses. The analysis was applied to the genes of t...

most highly pathogenic avian influenza viruses (aiv) emerge after field passage of non-pathogenic aivs in birds. the outbreak of low-pathogenic h7n1 avian influenza virus in italy during 1999-2000 followed by outbreak of highly pathogenic h7n1 avian influenza virus is one example in this regard. this experiment has been designed to investigate the effect of pre-infection of birds with lpai on s...

The transfer of six internal RNA segments from the avian influenza A/Mallard/New York/6750/78 (H2N2) virus reproducibly attenuates human influenza A viruses for squirrel monkeys and adult humans. To identify the avian influenza A virus genes that specify the attenuation and host range restriction of avian-human (ah) influenza A reassortant viruses (referred to as ah reassortants), we isolated s...