Journal of Neuroinfectious Diseases
Open Access

Powassan virus (POWV) is an emerging tick-borne flavivirus that poses a growing concern in North America. First identified in Powassan, Ontario, in 1958, the virus is primarily transmitted by Ixodes ticks, the same species responsible for spreading Lyme disease. Although relatively rare, cases of Powassan virus have increased in recent decades, particularly in the northeastern and Great Lakes regions of the United States and parts of Canada. Unlike some other tick-borne illnesses, POWV infection can progress rapidly and may lead to severe neurological complications, including encephalitis and meningitis. With no specific treatment or vaccine available, the virus represents a significant public health challenge [1,2].

Discussion

Powassan virus infection occurs when an infected tick transmits the pathogen during a bite. Unlike Lyme disease, which typically requires hours of tick attachment for transmission, POWV can be transmitted within 15–30 minutes. This rapid transmission increases the risk of infection and complicates prevention efforts. The incubation period ranges from one week to one month, after which patients may develop fever, headache, vomiting, and weakness. In more severe cases, neurological involvement leads to encephalitis, confusion, memory loss, seizures, and even paralysis [3,4].

Although many infections remain asymptomatic or mild, severe disease outcomes are concerning. Approximately 10% of individuals with encephalitis caused by POWV die, and about half of survivors experience long-term neurological problems such as recurrent headaches, muscle weakness, or cognitive impairment. The relatively small number of reported cases—typically fewer than 50 annually in the U.S.—may underrepresent the true burden due to underdiagnosis and lack of awareness among healthcare providers [5-8].

Ecologically, the virus is maintained in nature through cycles involving ticks and small mammals such as woodchucks, squirrels, and white-footed mice. As human populations expand into wooded habitats and climate change influences tick distribution, the risk of exposure is increasing. The overlap of POWV with other tick-borne pathogens like Borrelia burgdorferi (Lyme disease) raises the possibility of co-infections, complicating diagnosis and clinical management.

Currently, there is no antiviral therapy or vaccine for Powassan virus. Treatment is supportive, focusing on reducing symptoms and managing complications. Prevention remains the most effective approach, emphasizing strategies to reduce tick exposure. These include using insect repellents containing DEET or permethrin, wearing long sleeves and pants in tick-prone areas, performing tick checks after outdoor activities, and modifying outdoor environments to reduce tick habitats. Public health initiatives also stress the importance of awareness campaigns, particularly in regions with high tick activity [9,10].

Conclusion

Powassan virus, though rare, is a potentially severe tick-borne disease with growing significance in North America. Its rapid transmission, neurological complications, and lack of specific treatments underscore the need for vigilance. With tick populations expanding and human exposure increasing, the threat posed by POWV is likely to rise. Strengthening preventive measures, enhancing diagnostic capacity, and supporting research into vaccines and therapies are critical steps in addressing this underrecognized public health issue. Ultimately, awareness and proactive prevention remain the best defenses against Powassan virus.

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