Identification of an additional N-glycosylation site and thermostable mutations within the hemagglutinin-neuraminidase gene of the Newcastle disease virus belonging to the VII.1.1 sub-genotype

Newcastle disease virus (NDV) is considered one of the most devastating avian viral patho-gens affecting the avian population, and it causes a significant economic burden on the poultry industry worldwide. The study aimed to gain deeper understanding of the molecular and phylogenetic analyses of the complete hemagglutinin-neuraminidase (HN) coding region among NDV isolates. The samples were obtained from different parts of Iran from July 2017 to February 2020, were used for phylogenic analysis in this study. The results confirmed the predominance of sub-genotype VII.1.1, previously known as sub-genotype VIIL, which is circulating in commercial broiler farms of Iran. Identification of (a) an additional N-glycosylation site (NIS) at position 144; (b) mutations S315P and I369V which are related to increasing the viral thermostability; (C) cysteine residues at positions 123; (d) amino acid substitutions in the HN antigenic sites, especially the mutations I514V and E347Q, as well as the other mutant within HN binding sites of the VII.1.1 sub-genotype, suggests the idea that this new sub-genotype of NDV may possess a high level of pathogenicity and virulence compared to other NDV sub-genotypes. In conclusion, the results indicate the presence of an additional NIS at position 144, which may alter the virulence of the isolates. Furthermore, the presence of the thermostable mutations (S315P and I369V) and the other amino acid substitutions among the VII.1.1 sub-genotype isolates may have an impact on the vaccine immunity against this new NDV sub-genotype.

Molecular characterization and phylogenetic study of the hemagglutinin-neuraminidase gene of newcastle disease virus isolated from peacock (Pavo cristatus) and Turkey (Meleagris) and its comparison with broiler isolates

Newcastle disease has been endemic within the Iranian poultry industry for decades. However, the genetic nature of the circulating Hemagglutinin-Neuraminidase (HN) gene among Iranian domesticated bird populations is broadly unexplored. The presented study was carried out to gain insights into the biological and molecular characterization of four complete HN genes isolated from turkey, peacock, and broiler isolates in Iran between 2018 and 2020. The phylogenetic analysis revealed that the isolates belong to the Newcastle disease virus (NDV) subgenotype VII.1.1, previously known as VIIL. Further analysis demonstrated the thermostable substitutions S315P and I369V within the isolates. Finding the N-glycosylation site (NIS) at positions 144-146 and the cysteine residue 123 might influence the fusogenicity abilities of the isolates, while identification of multiple amino acid substitutions in both antigenic sites, especially I514V and E347Q, and the binding sites of the HN protein, raised concern about the pathogenicity of the isolates. In addition, the annual rate of change based on the HN gene of Iranian NDV was calculated at about 1.8088E-3 between 2011 and 2020. In conclusion, a new NDV variant with multiple site mutagenesis is circulating not only among chickens but also in turkey and captive birds such as peafowls, and failure of routine vaccination programs could be attributed to the differences between circulating NDV strains and those used in vaccine manufacturing. Therefore, future legislation aimed at providing vaster vaccination cover and biosecurity plans will be needed to control the spread of circulating NDV strains.

Vaccine development for zoonotic viral diseases caused by positive‑sense single‑stranded RNA viruses belonging to the Coronaviridae and Togaviridae families (Review)

Outbreaks of zoonotic viral diseases pose a severe threat to public health and economies worldwide, with this currently being more prominent than it previously was human history. These emergency zoonotic diseases that originated and transmitted from vertebrates to humans have been estimated to account for approximately one billion cases of illness and have caused millions of deaths worldwide annually. The recent emergence of severe acute respiratory syndrome coronavirus-2 (coronavirus disease 2019) is an excellent example of the unpredictable public health threat causing a pandemic. The present review summarizes the literature data regarding the main vaccine developments in human clinical phase I, II and III trials against the zoonotic positive-sense single-stranded RNA viruses belonging to the Coronavirus and Alphavirus genera, including severe acute respiratory syndrome, Middle east respiratory syndrome, Venezuelan equine encephalitis virus, Semliki Forest virus, Ross River virus, Chikungunya virus and O'nyong-nyong virus. That there are neither vaccines nor effective antiviral drugs available against most of these viruses is undeniable. Therefore, new explosive outbreaks of these zoonotic viruses may surely be expected. The present comprehensive review provides an update on the status of vaccine development in different clinical trials against these viruses, as well as an overview of the present results of these trials.