scholarly journals Molecular Characterization of Hemorrhagic Enteritis Virus (HEV) Obtained from Clinical Samples in Western Canada 2017–2018

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 941
Author(s):  
Victor Palomino-Tapia ◽  
Darko Mitevski ◽  
Tom Inglis ◽  
Frank van der Meer ◽  
Mohamed Faizal Abdul-Careem
Keyword(s):  
Bacterial Infections ◽  
Point Mutations ◽  
Clinical Samples ◽  
Western Canada ◽  
Viral Genomes ◽  
Field Type ◽  
Hemorrhagic Enteritis ◽  
Enteritis Virus ◽  
Hemorrhagic Enteritis Virus

Hemorrhagic enteritis virus (HEV) is an immunosuppressive adenovirus that causes an acute clinical disease characterized by hemorrhagic gastroenteritis in 4-week-old turkeys and older. Recurrent incidence of secondary infections (e.g., systemic bacterial infections, cellulitis, and elevated mortality), may be associated with the presence of field-type HEV in Canadian turkey farms. We speculate that field-type HEV and vaccine/vaccine-like strains can be differentiated through analysis of the viral genomes, hexon genes, and the specific virulence factors (e.g., ORF1, E3, and fib knob domain). Nine out of sixteen spleens obtained from cases suspected of immunosuppression by HEV were analyzed. The limited data obtained showed that: (1) field-type HEV circulates in many non-vaccinated western Canadian flocks; (2) field-type HEV circulates in vaccinated flocks with increased recurrent bacterial infections; and (3) the existence of novel point mutations in hexon, ORF1, E3, and specially fib knob domains. This is the first publication showing the circulation of wild-type HEV in HEV-vaccinated flocks in Western Canada, and the usefulness of a novel procedure that allows whole genome sequencing of HEV directly from spleens, without passaging in cell culture or passaging in vivo. Further studies focusing more samples are required to confirm our observations and investigate possible vaccination failure.

scholarly journals Extending the Coding Potential of Viral Genomes with Overlapping Antisense ORFs: A Case for the De Novo Creation of the Gene Encoding the Antisense Protein ASP of HIV-1

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 146
Author(s):  
Angelo Pavesi ◽  
Fabio Romerio
Keyword(s):  
De Novo ◽  
Point Mutations ◽  
Selective Advantage ◽  
Genomic Region ◽  
Fine Tuning ◽  
Sequence Evolution ◽  
Viral Genomes ◽  
Stop Codons ◽  
Hiv 1

Gene overprinting occurs when point mutations within a genomic region with an existing coding sequence create a new one in another reading frame. This process is quite frequent in viral genomes either to maximize the amount of information that they encode or in response to strong selective pressure. The most frequent scenario involves two different reading frames in the same DNA strand (sense overlap). Much less frequent are cases of overlapping genes that are encoded on opposite DNA strands (antisense overlap). One such example is the antisense ORF, asp in the minus strand of the HIV-1 genome overlapping the env gene. The asp gene is highly conserved in pandemic HIV-1 strains of group M, and it is absent in non-pandemic HIV-1 groups, HIV-2, and lentiviruses infecting non-human primates, suggesting that the ~190-amino acid protein that is expressed from this gene (ASP) may play a role in virus spread. While the function of ASP in the virus life cycle remains to be elucidated, mounting evidence from several research groups indicates that ASP is expressed in vivo. There are two alternative hypotheses that could be envisioned to explain the origin of the asp ORF. On one hand, asp may have originally been present in the ancestor of contemporary lentiviruses, and subsequently lost in all descendants except for most HIV-1 strains of group M due to selective advantage. Alternatively, the asp ORF may have originated very recently with the emergence of group M HIV-1 strains from SIVcpz. Here, we used a combination of computational and statistical approaches to study the genomic region of env in primate lentiviruses to shed light on the origin, structure, and sequence evolution of the asp ORF. The results emerging from our studies support the hypothesis of a recent de novo addition of the antisense ORF to the HIV-1 genome through a process that entailed progressive removal of existing internal stop codons from SIV strains to HIV-1 strains of group M, and fine tuning of the codon sequence in env that reduced the chances of new stop codons occurring in asp. Altogether, the study supports the notion that the HIV-1 asp gene encodes an accessory protein, providing a selective advantage to the virus.

Propagation of an Avirulent Turkey Hemorrhagic Enteritis Virus Isolate in Chickens

2018 ◽  
Vol 62 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Priscilla F. Gerber ◽  
Mohammad F. Hossain ◽  
Paul Reynolds ◽  
Phuong Hoang ◽  
Susan K. Burgess ◽  
...  
Keyword(s):  
Virus Isolate ◽  
Hemorrhagic Enteritis ◽  
Enteritis Virus ◽  
Hemorrhagic Enteritis Virus

Persistent Infection of Turkeys with an Avirulent Strain of Turkey Hemorrhagic Enteritis Virus

2009 ◽  
Vol 53 (3) ◽  
pp. 370-375 ◽  
Author(s):  
Nathan M. Beach ◽  
R. B. Duncan ◽  
C. T. Larsen ◽  
X. J. Meng ◽  
N. Sriranganathan ◽  
...  
Keyword(s):  
Persistent Infection ◽  
Avirulent Strain ◽  
Hemorrhagic Enteritis ◽  
Enteritis Virus ◽  
Hemorrhagic Enteritis Virus
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