Study Examines Persistent Powassan Disease in Mice

mBio (Scroggs, S., et al.) 2.21.23, published “Of MurinesPersistent Powassan Disease and Humans: Modeling Persistent Powassan Disease in C57BL/6 Mice.” The purpose of the study was to better understand how Powassan virus lineage I (POWV) and lineage II (known as deer tick virus [DTV]) cause long-term symptoms in addition to examining the potential role of viral persistence for the purpose of therapy development.

Six-week-old C57BL/6 mice were inoculated and assayed for infectious virus, viral RNA, and inflammation. While most of the mice were viremic, only 21% were symptomatic and 83% recovered. Infectious virus was detected only in brain samples that were taken during acute infection. Magnitude of viral RNA was detected in the brain but decreased over time. Encephalitis and meningitis were visible in acute mice as well as from mice sampled at 21 dpi. Low level inflammation was noted until 56 dpi in the brain and 84 dpi in the spinal cord.

Results of the study suggest that the long-term neurological symptoms that have been linked with Powassan disease are most likely caused by remaining viral RNA and chronic central nervous system inflammation as opposed to a persistent, active viral infection.  

For more information:

Read the study in mBio.

Read more about Powassan virus.