Powassan virus is a tickborne flavivirus that was first discovered in Powassan Ontario in 1958 when the virus was isolated from the brain tissue of a fatal pediatric encephalitis case. Though Powassan virus was first discovered in Ontario there has been limited surveillance in Canada to determine the prevalence of this virus in Canadian ticks. The symptoms of Powassan virus infection can include fever, headache, vomiting, weakness, seizures, encephalitis and meningitis, with approximately 10% of cases of encephalitis being fatal (CDC). To date there is no standardized testing or treatments for humans infected with Powassan virus, although many require hospital stays. Like with other flaviviruses, children, the elderly and immune compromised individuals are more at risk.

In North America there are two known strains of Powassan virus vectored by ticks, Powassan virus lineage 1 and Powassan virus lineage 2 (deer tick virus). Powassan virus lineage 1 has been found mainly in Ixodes cookei (groundhog ticks), Ixodes marxi (squirrel ticks), and Ixodes scapularis (blacklegged ticks), whereas deer tick virus is largely vectored by Ixodes scapularis (Emerg Microbes Infect). Though rare, Powassan virus has also been detected in Dermacentor andersoni (Rocky Mountain wood tick) (Emerg Microbes Infect). All of these tick species are established in Canada and represent almost 85% of the ticks submitted to Geneticks each year (Geneticks). This provides a unique opportunity for Powassan virus surveillance at Geneticks going forward.

Though data on Powassan virus in Canada is limited, surveillance data was recently published for our neighbors in New York state. Between 2007-2019 the New York State Department of Health collected and tested for Powassan virus in approximately 61, 900 Ixodes scapularis ticks collected from public land across New York State. A total of 181 pools tested positive for Powassan virus lineage 2 (deer tick virus) and two pools tested positive for Powassan virus lineage 1 (for research purposes ticks are often pooled for testing instead of individual testing) (Emerg Microbes Infect). Their testing demonstrated the importance of testing Ixodes scapularis ticks for deer tick virus (Powassan lineage 2).

The Geneticks team has worked hard to develop testing for both Powassan virus lineage 1 and 2 so that we can offer this testing to our customers. Due to the lack of human testing for Powassan virus we understand how important it is to be able to identify if the tick that bite you or your loved one was a carrier of this virus.

Sources

(CDC) Center for Disease Control and Prevention: Powassan Virus: Symptoms, Diagnosis, and Treatment.

(Emerg Microbes Infect) Emerg Microbes Infect. 2023; 12(1): Identification and characterization of novel lineage 1 Powassan virus strains in New York State. Lange RE, Dupuis Ii AP, Prusinski MA, Maffei JG, Koetzner CA, Ngo K, Backenson B, Oliver J, Vogels CBF, Grubaugh ND, Kramer LD, Ciota AT.

(Geneticks) Geneticks Statistics Center: Canada 2018-2022 data, Tick Species Composition: 2018-2022