REVIEW | doi:10.20944/preprints201906.0085.v1
Subject: Life Sciences, Virology Keywords: H9N2; avian influenza viruses; zoonotic; pandemic potential; poultry
Online: 11 June 2019 (07:44:44 CEST)
H9N2 avian influenza viruses have become globally widespread in poultry over the last two decades and represent a genuine threat both to the global poultry industry but also humans through their high rates of zoonotic infection and pandemic potential. H9N2 viruses are generally hyperendemic in effected countries and have been found in poultry in many new regions in recent years. In this review we examine the current global spread of H9N2 avian influenza viruses as well as their host range, tropism, transmission routes and the risk posed by these viruses to human health.
REVIEW | doi:10.20944/preprints201905.0273.v1
Subject: Biology, Animal Sciences & Zoology Keywords: influenza virus; vaccines; passive immunization; immunotherapeutics
Online: 22 May 2019 (11:31:15 CEST)
Influenza is a disease that poses a significant health burden worldwide. Vaccination is the best way to prevent influenza virus infections. However, conventional vaccines are only effective for a short period of time due to the propensity of influenza viruses to undergo antigenic drift and antigenic shift. The efficacy of these vaccines is uncertain from year-to-year due to potential mismatching between the circulating viruses and vaccine strains, mutations arising due to egg adaptation, and potential contamination of the vaccine virus stock. Subsequently, the inability to store these vaccines long-term and vaccine shortages are challenges that need to be overcome. Conventional vaccines are also less effective for certain populations, including the young, old, and immunocompromised. This warrants for diverse efficacious vaccine developmental approaches, involving both active and passive immunization. As opposed to active immunization platforms (requiring the use of whole or portions of pathogens as vaccines), the rapidly developing passive immunization involves administration of either pathogen-specific or broadly acting antibodies against a kind or class of pathogens as a prophylactic treatment to corresponding acute infection. Several antibodies with broadly acting capacities have been discovered that may serve as means to suppress influenza viral infection and allow the process of natural immunity to engage opsonized pathogens whilst boosting immune system by antibody-dependent mechanisms that bridge the innate and adaptive arms. By that, passive immunotherapeutics approach assumes a robust tool that could aid control of influenza viruses. In this review, we comment on some improvements in influenza management and promising vaccine development platforms, with emphasis on the capacity of passive immunotherapeutics especially when coupled with the use of antivirals in the management of influenza infection.
ARTICLE | doi:10.20944/preprints202208.0338.v1
Subject: Life Sciences, Virology Keywords: migratory birds; Newcastle disease virus-GVII; poultry; phylogenetics; sequence-independent; sin-gle-primer amplification (SISPA); velogenic; whole genome sequencing (WGS)
Online: 18 August 2022 (10:40:10 CEST)
Newcastle disease virus (NDV) genotype VII is a highly pathogenic Orthoavulavirus that has caused multiple outbreaks among poultry in Egypt since 2011. This study aimed to investigate the genetic diversity of NDV prevailing in domestic and wild birds in Egyptian governorates. A total of 37 oropharyngeal swabs from wild birds and 101 swabs from domestic bird flocks including chickens, ducks, turkeys, and swans were collected from different geographic regions within 13 governorates during 2019-2020. Virus isolation and propagation via embryonated eggs revealed 91 swab samples produced allantoic fluid containing hemagglutination activity, suggestive of virus presence. The use of RT-PCR targeted to F gene successfully detected NDV in 85 samples. The geographical prevalence of NDV spread to 12 governorates in domestic birds, migratory and non-migratory wild birds. Following whole genome sequencing, we assembled six NDV genome sequences (70 - 99% of genome coverage), including five full F gene sequences. All NDV strains carried high virulence, based on the presence of polybasic amino acids (RRQRF) at the F gene cleavage site. Phylogenetic analysis revealed that the NDV strains belonged to class II within genotype VII.1.1. The presence of genetically similar virulent NDV in wild birds further highlights their role in the dissemination of NDV in poultry populations across Egypt. Continued genomic surveillance in both wild birds and poultry would be necessary for monitoring NDV incursions and genetic diversification.