Doctors record first-ever case of deadly tick-borne virus in the UK: 'It's a really common problem that was absent 20 or 30 years ago'

Rising temperatures in the United Kingdom have created an ideal environment for ticks to thrive in, paving the way for them to spread a virus in a population that is largely unprotected against it.

What happened?

A mountain biker riding through North Yorkshire Moors National Park in 2022 became the first confirmed person in the U.K. to contract encephalitis — or swelling of the brain — after getting bit by at least one black-legged tick.

The man began experiencing fatigue, muscle pain, and fever after five days but eventually regained some health. However, he began to lose coordination about a week later, and an MRI scan showed that he had developed encephalitis.

Though the virus was discovered nearly a century ago and has largely remained in Europe and northern Asia, Earth's overheating has allowed encephalitis-carrying arachnids to venture to new territories.

"It's a really common problem that was absent 20 or 30 years ago," said Gábor Földvári, an expert at the Center for Ecological Research in Hungary, per Grist.

Why is the tick migration concerning?

Tick-borne encephalopathy is deadlier than other diseases spread by the parasite because of how easily it can move from country to country, thus making it harder to contain and treat.

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Following an incubation period that typically lasts one to two weeks, patients will exhibit symptoms such as fatigue, headache, and fever, according to the World Health Organization. About 15% of infected individuals will experience a more severe second phase that affects the central nervous system and typically leads to hospitalization.

While the most extreme cases are fatal, survivors of TBE have "lingering neurological problems, such as sleeplessness and aggressiveness," Grist noted.

The WHO stated that there are 10,000 to 12,000 reported cases annually of encephalopathy, but actual numbers may be much higher. Additionally, it's an issue that will only get worse should the planet's overheating continue on its current trajectory.

The average temperature in the U.K. from 1991-2020 was 0.8 degrees Celsius (1.4 degrees Fahrenheit) warmer than the previous three decades, per the Meteorological Office. That trend has coincided with the rise in reported cases of TBE since the 1990s.

Warmer climates and milder winters have extended the window for ticks and other creatures that feed on blood to breed and feed while allowing them to move to previously inhospitable areas. Thus, experts have become wary of TBE.

"The number of overwintering ticks is increasing, and in spring there is high activity of ticks," said Gerhard Dobler, a doctor at the German Center for Infection Research. "This may increase the contact between infected ticks and humans and cause more disease."

What can I do to protect myself?

Taking precautionary measures when exploring the outdoors, like wearing clothes that cover your entire body and spraying repellent, is the best way to prevent ticks from latching to your skin. The Centers for Disease Control and Prevention also recommends checking your clothes, skin, and pets after returning home.

Grist mentioned two vaccines to combat TBE, but neither covers all three of the most prevalent subtypes.

As such, some experts have called for the development of a new vaccine that is more effective against all variants of TBE.

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