Genomic nucleotide-based distance analysis for delimiting old world monkey derived herpes simplex virus species

Area of Science:

• Virology
• Genomics
• Phylogenetics

Background:

• Old World Monkey (OWM) alphaherpesviruses include Macacine alphaherpesvirus 1 (herpes B), Cercopithecine alphaherpesvirus 2 (SA8), and Papiine alphaherpesvirus 2 (herpes papio).
• Herpes B is a significant biosafety concern, while SA8 and herpes papio are considered less virulent in humans.
• Recent advances in next-generation sequencing (NGS) facilitate comprehensive phylogenetic studies of OWM herpes simplex viruses.

Purpose of the Study:

• To investigate the species status of OWM herpes simplex viruses using phylogenetic networks and genetic distance cutoff methods.
• To analyze 27 OWM herpes simplex isolates based on their genomic data.

Main Methods:

• Phylogenetic networks were employed to analyze genetic relationships among OWM herpes simplex virus isolates.
• A genome-based genetic distance cutoff method was established to differentiate viral species.
• Genetic distances were calculated between various OWM herpes simplex virus strains, including lion and pig-tailed isolates versus herpes B core strains.

Main Results:

• Genetic distances between lion and pig-tailed simplex viruses and herpes B core strains exceeded those between SA8 and herpes papio.
• A species distance cutoff of 8.94% was determined.
• The analysis confirmed separate species status for SA8 and herpes papio and indicated that lion and pig-tailed simplex viruses are distinct from herpes B core strains, surpassing the species cutoff.

Conclusions:

• Lion and pig-tailed simplex viruses should be designated as separate viral species.
• This classification may represent the first identification of viral cryptic species.
• The findings contribute to a refined understanding of OWM alphaherpesvirus taxonomy and evolution.