{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T19:50:49Z","timestamp":1792525849759,"version":"4.5.0"},"reference-count":63,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2023,11,26]],"date-time":"2023-11-26T00:00:00Z","timestamp":1700956800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["TropicalMed"],"abstract":"<jats:p>Background: Powassan virus is an emerging neurotropic arbovirus transmitted by the tick Ixodes scapularis. This systematic review was conducted to aggregate data on its clinical manifestations, diagnostic findings, and complications. Methods: PubMed was searched until August 2023 using the term \u201cPowassan\u201d, to identify all published cases of Powassan virus infections, as per PRISMA guidelines. Results: Among the 380 abstracts identified, 45 studies describing 84 cases (70 adult, 14 pediatric) were included. Cases were reported from the USA and Canada. Complications included paralysis in 44.1% of adult and 42.6% of pediatric cases, cognitive deficits in 33.3% of adult and 25% of pediatric cases, while the mortality rate was 19.1% and 7.1% in the adult and pediatric populations, respectively. Correlation analysis revealed an association between mortality and age (r = 0.264, p = 0.029), development of paralysis (r = 0.252, p = 0.041), or respiratory distress or failure (r = 0.328, p = 0.006). Factors associated with persistent neurological deficits were development of ataxia (r = 0.383, p = 0.006), paralysis (r = 0.278, p = 0.048), speech disorder (r = 0.319, p = 0.022), and cranial nerve involvement (r = 0.322, p = 0.017). Other significant correlations included those between speech disorders and ataxia (r = 0.526, p &lt; 0.001), and between paralysis and respiratory distress or failure (r = 0.349, p = 0.003). Conclusion: Powassan virus infections have significant morbidity and mortality and should be suspected in cases of encephalitis and possible tick exposure. PROSPERO registration number: CRD42023395991.<\/jats:p>","DOI":"10.3390\/tropicalmed8120508","type":"journal-article","created":{"date-parts":[[2023,11,27]],"date-time":"2023-11-27T03:35:06Z","timestamp":1701056106000},"page":"508","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":25,"title":["Powassan Virus Infections: A Systematic Review of Published Cases"],"prefix":"10.3390","volume":"8","author":[{"given":"Loukas","family":"Kakoullis","sequence":"first","affiliation":[{"name":"Department of Medicine, Mount Auburn Hospital, Cambridge, MA 02138, USA"},{"name":"Harvard Medical School, Boston, MA 02115, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Victor Renault","family":"Vaz","sequence":"additional","affiliation":[{"name":"Department of Medicine, Mount Auburn Hospital, Cambridge, MA 02138, USA"},{"name":"Harvard Medical School, Boston, MA 02115, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Divmehar","family":"Kaur","sequence":"additional","affiliation":[{"name":"Department of Medicine, Mount Auburn Hospital, Cambridge, MA 02138, USA"},{"name":"Harvard Medical School, Boston, MA 02115, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sonia","family":"Kakoulli","sequence":"additional","affiliation":[{"name":"Medical School, University of Groningen, 9712 Groningen, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"George","family":"Panos","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Medicine, School of Health Sciences, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lin H.","family":"Chen","sequence":"additional","affiliation":[{"name":"Harvard Medical School, Boston, MA 02115, USA"},{"name":"Division of Infectious Diseases and Travel Medicine, Department of Medicine, Mount Auburn Hospital, Cambridge, MA 02138, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irmgard","family":"Behlau","sequence":"additional","affiliation":[{"name":"Harvard Medical School, Boston, MA 02115, USA"},{"name":"Division of Infectious Diseases and Travel Medicine, Department of Medicine, Mount Auburn Hospital, Cambridge, MA 02138, USA"},{"name":"Molecular Biology and Microbiology and Ophthalmology, Tufts Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,11,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"453","DOI":"10.1089\/vbz.2017.2110","article-title":"Powassan Virus: An Emerging Arbovirus of Public Health Concern in North America","volume":"17","author":"Hermance","year":"2017","journal-title":"Vector Borne Zoonotic Dis."},{"key":"ref_2","first-page":"1","article-title":"Tick-Borne Encephalitis Vaccine: Recommendations of the Advisory Committee on Immunization Practices, United States, 2023","volume":"72","author":"Hills","year":"2023","journal-title":"Morb. 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