Powassan Virus Hit a Record High in 2025 — And New England Is Still Counting Cases

CDC data cited in recent reporting shows that 2025 was the worst year on record for Powassan virus in the United States, with 76 confirmed cases nationally — more than triple the 24 cases reported just four years earlier, and well above the roughly 7 to 8 cases per year the country had typically logged before this recent climb. Powassan remains genuinely rare compared to tick-borne illnesses like Lyme disease, but it's drawing increasing attention from state health departments because of how serious it can be once someone is infected, and because, unlike Lyme, there's no vaccine and no specific treatment available.

What makes Powassan different from more familiar tick-borne illnesses

Lyme disease is caused by bacteria, which means it generally responds to antibiotics. Powassan is viral, and treatment for it is limited to managing symptoms rather than clearing the infection directly. The virus is carried mainly by deer ticks (the same species responsible for most Lyme disease transmission) and woodchuck ticks. Reporting on the virus commonly cites that Powassan can transmit in as little as 15 minutes after a tick attaches, compared to the 16-to-24-hour window typically needed for Lyme bacteria to transmit — a commonly repeated figure rather than one directly published by the CDC, but one that underscores why quick tick checks after outdoor exposure matter even for a short walk through grass or brush.

How serious an infection can get

Early symptoms include fever, headache, vomiting, and weakness — nonspecific enough that many cases likely go unrecognized or unreported, which experts say means the real case count is probably higher than official figures show. In more severe cases, the virus can cause encephalitis (brain inflammation) or meningitis. Of the 476 Powassan cases the CDC recorded nationally between 2004 and 2025, 63 were fatal — and among cases that progress to neuroinvasive disease (affecting the brain or spinal cord), roughly 1 in 10 are fatal, a meaningfully higher fatality rate than most other tick-borne illnesses in the US.

New England's 2026 season, case by case

Rhode Island's Department of Health confirmed its third Powassan case of 2026 on September 21, involving a man in his 60s from Washington County who began experiencing symptoms in late August. That brought Rhode Island's total to 11 confirmed cases since the state first identified Powassan in 2016 — a meaningful share of the state's decade-long total landing in a single year. Earlier 2026 Rhode Island cases involved a Providence County man in his 60s (reported in June) and a Newport County man in his 70s (symptoms beginning in late July). Maine, meanwhile, reported its fourth Powassan case of 2026 by late August, this one from Penobscot County, according to the state's Weekly Arboviral Surveillance Report. A University of Wisconsin entomologist, commenting on the broader 2026 tick season, noted that early reports suggested 2026 could turn out to be a heavy tick year generally, a pattern consistent with the case activity New England has reported so far.

What public health guidance actually recommends

Because there's no vaccine or targeted treatment, Rhode Island health officials' guidance after the September case centered entirely on prevention: use an EPA-approved insect repellent, avoid walking through brush and tall grass where ticks wait to attach to a passing host, and check yourself, children, and pets for ticks after any time spent outdoors. That's broadly consistent with standard tick-bite prevention guidance used for other tick-borne diseases as well, but the emphasis carries more weight with Powassan specifically, given both its faster transmission window and the absence of any treatment once someone is infected.

• CDC data shows 2025 was a record year for Powassan virus nationally, with 76 cases — more than triple the count from four years earlier.
• Powassan is viral (unlike bacterial Lyme disease), with no vaccine and no specific treatment; care is limited to managing symptoms.
• The virus is carried mainly by deer ticks and woodchuck ticks, and is commonly described as transmitting faster than Lyme bacteria.
• Of 476 US cases recorded 2004-2025, 63 were fatal; roughly 10% of neuroinvasive cases are fatal.
• Rhode Island confirmed its third 2026 case on September 21 (Washington County), bringing its total to 11 cases since 2016; Maine reported its fourth 2026 case by late August (Penobscot County).
• With no treatment available, official guidance focuses entirely on prevention: EPA-approved repellent, avoiding brush and tall grass, and prompt tick checks after outdoor exposure.

Powassan's rarity means most tick bites won't involve it, but the lack of any treatment once infected is exactly why reducing tick exposure around a home matters year-round, not just during an active case cluster. A free Sevacorp inspection can help identify conditions on a property — overgrown vegetation, leaf litter, brush piles — that tend to support tick activity close to where people spend time outdoors.

• Sources:
• Rhode Island Department of Health — "RIDOH Confirms Case of Rare Tick-Borne Viral Infection, Powassan" — https://health.ri.gov/press-releases/ridoh-confirms-case-rare-tick-borne-viral-infection-powassan-1
• WAGM-TV — "Maine reports third Powassan virus case of 2026; health experts encourage tick precautions" — https://www.wagmtv.com/2026/07/28/maine-reports-third-powassan-virus-case-2026-health-experts-encourage-tick-precautions/
• Healio — "CDC reports rise in rare, deadly tickborne illness" — https://www.healio.com/news/infectious-disease/20260702/cdc-reports-rise-in-rare-deadly-tickborne-illness
• Fox News — "Rare tick-borne virus turns deadly fast as US cases reach record high, experts warn" — https://www.foxnews.com/health/rare-tick-borne-virus-turns-deadly-fast-us-cases-reach-record-high-experts-warn
• Rhode Island Current — "Second Powassan case of 2026 confirmed; RI health officials urge precautions to reduce tick exposure" — https://rhodeislandcurrent.com/?p=32800