A Novel Human Acute Encephalitis Caused by Pseudorabies Virus Variant Strain

Area of Science:

• Virology
• Infectious Diseases
• Public Health

Background:

• Pseudorabies virus (PRV) is a significant pathogen in swine populations.
• Human infections with PRV are exceptionally rare, with no prior isolation from human cases.

Purpose of the Study:

• To investigate and confirm PRV as the causative agent in human encephalitis cases.
• To isolate and characterize the PRV strain from human patients.
• To assess the genetic relationship and pathogenicity of the human-derived PRV strain.

Main Methods:

• Clinical diagnosis and metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF).
• Virus isolation and identification using transmission electron microscopy.
• Serological detection of PRV antibodies (gB, gE, neutralizing antibodies).
• Phylogenetic analysis and etiological characterization of the isolated strain.

Main Results:

• Four human encephalitis cases were confirmed as PRV infections.
• PRV-specific sequences were detected in CSF samples via mNGS.
• A novel PRV strain, hSD-1/2019, was successfully isolated from human CSF, exhibiting typical swine PRV morphology.
• Phylogenetic analysis revealed hSD-1/2019 is closely related to circulating Chinese swine PRV variant strains.
• The isolated strain demonstrated high pathogenicity in pigs, causing acute neurological symptoms.

Conclusions:

• This study reports the first isolation of PRV from human encephalitis.
• The findings indicate a close genetic and etiological relationship between the human isolate and Chinese swine PRV variants.
• The successful isolation underscores the significant risk of PRV zoonotic transmission from pigs to humans.