There have been three influenza pandemics during the past century — in 1918, 1957, and 1968. Although the severity of the epidemics and the primary age groups affected varied, each was caused by a novel type A virus of avian origin. In 1957 and 1968, the new viruses had components of previous human viruses as well as avian viruses. The genome of the influenzavirus is made up of eight segments o...

Abstract Background Influenza viruses are a continuous threat to avian and mammalian species, causing epidemics pandemics. After the circulation of H5N1 in 2006, 2015, 2016 Iraq, an H5N8 influenza virus emerged domestic geese Sulaymaniyah Province, Iraq. This study analyzed genetic characteristics Iraqi viruses. Results An HPAI subtype was identified from backyard Kurdistan Region, north Phylog...

For viruses such as avian influenza, immunity within a host population can drive the emergence of new strains by selecting for viruses with novel antigens that avoid immune recognition. The accumulation of acquired immunity with age is hypothesized to affect how influenza viruses emerge and spread in species of different lifespans. Despite its importance for understanding the behaviour of avian...

Assessing influenza A virus strains circulating in animals and their potential to cross the species barrier and cause human infections is important to improve human influenza surveillance and preparedness. We reviewed studies describing serological evidence of human exposure to animal influenza viruses. Comparing serological data is difficult due to a lack of standardisation in study designs an...

backgrounds and objectives: classified as low pathogenic avian influenza (lpai) viruses, the h9n2 subtype causes severe respiratory disease in poultry farms and occasional respiratory disease in humans. in this study, the neuraminidase (na) gene of three avian influenza (ai) h9n2 strains isolated from poultry farms in iran during 2010-11, as well as other reported iranian h9n2 isolates, were ge...

Influenza viruses belong to the Orthomyxoviridae family, genus Orthomyxovirus, and are divided into three types – A, B, and C – based on the antigenic differences between their nucleoprotein and matrix proteins. Influenza A viruses are further subdivided into several subtypes. A most striking feature of influenza viruses is their ability to continually change their genetic structure – in partic...

During the last decade the number of reported outbreaks caused by highly pathogenic avian influenza (HPAI) in domestic poultry has drastically increased. At the same time, low pathogenic avian influenza (LPAI) strains, such as H9N2 in many parts of the Middle East and Asia and H6N2 in live bird markets in California, have become endemic. Each AI outbreak brings the concomitant possibility of po...

Since the mid-1970s, Hong Kong has functioned as an influenza sentinel post for southern China, a region identified as a hypothetical epicentre for the emergence of pandemic influenza viruses. Nineteen ninety-seven marked the coming-of-age of animal-influenza studies with the recognition in Hong Kong of an incipient pandemic situation brought about by the infection of chicken and humans with an...

Direct transmission of avian influenza viruses to mammals has become an increasingly investigated topic during the past decade; however, isolates that have been primarily investigated are typically ones originating from human or poultry outbreaks. Currently there is minimal comparative information on the behavior of the innumerable viruses that exist in the natural wild bird host. We have previ...

Reverse transcriptase PCR designed to amplify the N1 to N9 neuraminidase (NA) genes of avian influenza viruses detected 118 of the 119 NA genes tested (99.2%) in a subtype-specific manner. This technique successfully subtyped all 167 recent avian influenza viruses isolated from birds. Subtype specificity was confirmed by sequence analyses of all 285 PCR products.