History of Powassan virus in Timeline

By Popular Timelines Editorial Team · Updated: August 6, 2025

Powassan virus (POWV) is a flavivirus transmitted by ticks, primarily found in North America and the Russian Far East. Named after Powassan, Ontario, where it was first identified, POWV can cause encephalitis, a dangerous inflammation of the brain. Currently, there are no approved vaccines or antiviral drugs specifically for Powassan virus. The primary method of prevention is avoiding tick bites. The virus belongs to the Orthoflavivirus genus.

1958: Discovery of Powassan Virus

In 1958, Powassan virus was identified in Powassan, Ontario, Canada, in a five-year-old boy named Lincoln Byers who died from encephalitis.

1970: First U.S. Human Case

In 1970, the first human case of Powassan virus in the United States was discovered in New Jersey.

1978: First Russian Case

In 1978, the first case of Powassan virus was discovered in Russia.

2001: Powassan Virus Cases in the U.S.

From 2001 to 2010, there were 33 confirmed cases of Powassan virus infection in the United States.

2002: POWV Listed as Notifiable Disease

In 2002, POWV was included in the list of nationally notifiable diseases to the U.S. Centers for Disease Control and Prevention (CDC).

2005: Increase in POWV Incidence Rate

The incidence rate of POWV in the U.S. was one case per year from 1958 to 2005, and has risen to 10 cases per year since then.

2009: POWV Cases Reported to CDC

Between 2009 and 2018, 133 cases of neuroinvasive POWV and 12 cases of non-neuroinvasive POWV were reported to the CDC.

2010: Powassan Virus Cases in the U.S.

From 2001 to 2010, there were 33 confirmed cases of Powassan virus infection in the United States.

2016: Kay Hagan contracts Powassan virus

In 2016, former U.S. Senator Kay Hagan contracted the Powassan virus.

2017: Connecticut Infant Case

In 2017, a rare case of a five-month-old Connecticut infant boy contracting Powassan virus infection was published. He survived with normal motor and verbal development on follow-up at the age of 10 months.

2018: POWV Cases Reported to CDC

Between 2009 and 2018, 133 cases of neuroinvasive POWV and 12 cases of non-neuroinvasive POWV were reported to the CDC.

October 28, 2019: Death of Kay Hagan

On October 28, 2019, former U.S. Senator Kay Hagan died at the age of 66 after contracting the Powassan virus in 2016.

2021: MaryAnn Harris contracts Powassan virus

In 2021, artist, author, and musician MaryAnn Harris contracted the Powassan virus and was subsequently paralyzed.

2022: Connecticut Case

In 2022, the Connecticut Department of Public Health confirmed that a man aged in his 50s contracted the Powassan virus in the state during March and was hospitalized with severe neurological symptoms. He was discharged to recover at home.

2023: Maine Death

In 2023, the Maine Center for Disease Control and Prevention reported that a 58-year-old man from Sagadahoc County died from Powassan virus.

June 3, 2024: Death of MaryAnn Harris

On June 3, 2024, artist, author, and musician MaryAnn Harris, spouse and longtime collaborator of Charles de Lint, died at age 71 after a long struggle with Powassan virus, which she contracted in 2021.