Powassan virus (POWV) is classified into the genus Flavivirus and is transmitted through ticks. The virus was found in North America and the Far East of Russia. POWV is an RNA virus that can be divided into two lineages, and Lineage II has the greatest genetic variability. The conservation of viral envelope proteins in the flaviviruses results in cross-neutralization reactions between different viruses. There are currently no vaccines or therapeutic drugs for POWV.