Powassan virus persistence after acute infection

Area of Science:

• Neuroscience
• Virology
• Infectious Diseases

Background:

• Survivors of Powassan encephalitis frequently experience long-term neurological deficits.
• Related flaviviruses like tick-borne encephalitis and West Nile Neuroinvasive Disease (WNND) also present with neurological sequelae.
• Existing models for WNND suggest prolonged presence of virus, RNA, and inflammation post-infection.

Purpose of the Study:

• To develop a mouse model that replicates key aspects of human Powassan encephalitis.
• To investigate the persistence of viral RNA and associated neuropathology in a Powassan encephalitis mouse model.
• To provide insights into the biological mechanisms underlying persistent neurological symptoms after Powassan encephalitis.

Main Methods:

• Development of a novel mouse model for studying Powassan encephalitis.
• Detection of viral RNA in the brain tissue of infected mice.
• Assessment of neuropathology, including myelitis, at extended time points post-infection.

Main Results:

• The established mouse model successfully replicated certain features of human Powassan encephalitis.
• Viral RNA was detected in the brain of mice more than two months after the initial acute infection.
• Evidence of myelitis was also observed in the mouse model at extended post-infection periods.

Conclusions:

• The developed mouse model is a valuable tool for studying persistent neurological disease after Powassan encephalitis.
• Findings suggest that Powassan virus can persist in the central nervous system, potentially contributing to long-term neurological damage.
• Further research, informed by studies on more prevalent flaviviral encephalitides, is needed to fully understand the basis of persistent symptoms.