Health experts are sounding the alarm about a tick-borne virus that poses a serious threat to brain health, as the United States experiences its most severe tick bite season in ten years.
The Powassan virus, though traditionally rare, has seen a steady increase in cases over the past five years. This rise is attributed to the warmer and wetter weather conditions that extend the active period for ticks.
Once a tick carrying the virus bites a person, transmission can occur within just 15 minutes. The virus can then reach the brain, causing inflammation that may result in severe complications such as speech difficulties, seizures, and even paralysis.
Approximately 50% of individuals who exhibit symptoms endure long-term neurological issues, and the disease proves fatal for up to 20% of those affected.
Concerns have intensified following the recent hospitalization of John Reagan, a former pharmacist and enthusiastic outdoorsman from New Hampshire, who was diagnosed with the virus.
Just four months into his retirement, the 66-year-old was taken to the hospital feeling ‘worn down’ days after suffering what he thought was an innocuous tick bite.
By the next day, friends said he could no longer speak and was struggling to move his limbs.
His wife Sharon Reagan told a local publication: ‘It’s a scary, scary, scary thing. We want people to be aware — be vigilant about finding and removing ticks.’
Experts are raising the alarm over the Powassan virus, which is spread by ticks, after it was detected in the US for the first time this yearÂ
About 20 to 50 cases of Powassan virus are reported in the US every year, although this tally has been exceeded for the last two years.
In 2025, a total of 76 cases were detected, mostly in the Northeast. Other tick-borne diseases, such as Lyme disease, are also surging nationwide.
Powassan virus is easily spread from infected ticks to humans, taking about 15 minutes to transfer after a bite, compared to 24 to 36 hours for Lyme disease. There is no visual way to tell whether a tick is infected with the virus.
Many patients who are bitten do not suffer any symptoms, but among those who do, warning signs of an infection emerge within one to five weeks.
In the early stages, patients suffer from a flu-like illness with symptoms including a fever, headache and vomiting.
In later stages, the virus can spread to the brain and cause encephalitis, or brain swelling, as well as an altered mental state.
A 2023 study found that after an infection, 44 percent of patients suffered from some form of paralysis, while 33 percent had a cognitive deficit.
There is no treatment for the disease, including an antiviral to fight the virus or a vaccine to prevent an infection.
John Reagan, 66, was just four months into his retirement when he was infected with the virus
Instead, doctors use supportive care to manage symptoms and help patients to battle the infection.
The best way to prevent an infection is to avoid tick bites – which experts recommend doing by wearing long-sleeved clothes and avoiding long grass – and to remove ticks rapidly after being bitten.
For Reagan, when he first started showing symptoms he was prescribed doxycycline, an antibiotic used to clear suspected Lyme disease infections.
When his symptoms progressed, however, he was hospitalized. Doctors then detected Powassan virus using tests.
He was hospitalized for two weeks, where staff also put him on a ventilator and a feeding tube.
This week, he was transferred to Massachusetts General Hospital for further treatment. His wife says he now needs intense rehab to aid his recovery.
Friend Tom Wright yesterday told WMUR9: ‘I talked to his wife this morning. He was moving his fingers and moving his toes, and even his eyelids were moving.Â
‘So, they have given him a drug to help him wake up and come out of this.’
He was treated at a Concord Hospital for two weeks before being transferred to Massachusetts General Hospital
The above shows the number of Powassan virus cases detected in the US every year since 2004
The above shows where in the US Powassan virus cases have been detected
His wife said they removed a tick after finding it lodged on him before he fell ill, although it was not clear where he had picked it up.
The 2026 tick season is already the worst in a decade, experts say, amid surging emergency department visits for the bites.
In June, there were 126 ED visits for tick bites per 100,000 ED visits, the CDC says, the highest number for the month since 2017. Every region except the South Central US had a higher ED bite rate than a decade ago.
Dr Alison Hinckley, an epidemiologist and Lyme disease expert at the CDC, said: ‘Tick season is here and these tiny biters can make you seriously sick.
‘If you develop a rash or fever in the days to weeks after a bite, or after being in an area with ticks, seek medical care promptly.’