Summary
- A 60-year-old male in Manitoba, Canada, was diagnosed with Powassan virus after being bitten by a black-legged tick.
- The patient experienced symptoms such as fever, weight loss, confusion, and neurological issues after the tick bite.
- Laboratory tests confirmed the presence of Powassan virus in the patient’s system.
- Powassan virus is transmitted by black-legged ticks and can lead to neuroinvasive disease with potentially fatal outcomes.
- Prevention strategies for Powassan virus include avoiding tick bites, using insect repellent, and frequent tick checks.
A 60-year-old outdoor photographer from southern Manitoba, Canada, developed severe symptoms two weeks after being bitten by a black-legged tick. Initially concerned about Lyme disease, he was prescribed doxycycline. However, his condition worsened, and by November 1, he was hospitalized with a high fever, significant weight loss, confusion, and severe weakness. Despite a thorough evaluation, including tests for various viral and bacterial infections, all results came back negative.
The turning point came when doctors tested for Powassan virus (POWV), a rare but serious tick-borne illness. The patient tested positive for POWV, which led to a diagnosis of Powassan encephalitis, a potentially life-threatening brain infection. Powassan virus is primarily spread by black-legged ticks, the same species that transmits Lyme disease. Unlike other tick-borne diseases, which usually require the tick to be attached for at least 24 hours, POWV can be transmitted in as little as 15 minutes.
The virus, although rare, has been reported in regions of Canada, the United States, and Russia. In the U.S., most cases occur in the northeastern states, particularly Wisconsin and Minnesota, with over 200 cases reported. Canada has reported significantly fewer cases, but the actual prevalence of POWV remains uncertain due to limited awareness and lack of reporting.
The patient in this case exhibited symptoms typical of POWV infection, including high fever, neurological impairments like confusion and ataxia, and radicular pain. His brain imaging showed subtle abnormalities, and tests of his cerebrospinal fluid confirmed the diagnosis. Although the patient improved after a week of supportive care, he continued to experience lingering effects such as ataxia for months after discharge.
Powassan virus is an emerging concern due to the expanding range of its tick vectors, which are moving further north each year. The virus’s high neuroinvasive potential and significant mortality rate make it a critical topic for healthcare providers, particularly in regions where black-legged ticks are prevalent. As no specific antiviral treatment exists for POWV, management focuses on supportive care, including measures to protect the airway and reduce brain swelling, as well as pain management.
The case highlights the need for increased awareness of POWV, especially in regions where ticks are common. Prevention strategies are vital, including avoiding tick habitats, using insect repellents, and treating clothing with permethrin. Frequent tick checks are also essential for those living or working in areas where ticks are active.
This case serves as a reminder to healthcare professionals to consider POWV in patients presenting with encephalitis symptoms, especially when other common tick-borne diseases have been ruled out. Continued research and public health efforts are needed to better understand and mitigate the risks associated with this emerging virus.
Infectious Diseases, Emergency Medicine, Neurology