Experts warn of deadly tick-borne Powassan virus

Though Lyme disease is the most prevalent — and most well-known — tick-borne virus, it isn't the only reason to take extra precautions when walking in the woods.

Tick season is upon us and experts say this could be a "particularly bad year," as they're seeing greater numbers of ticks in more areas of the country.

Dr. Susan Paskewitz, the chair of the department of entomology at the University of Wisconsin-Madison, has been studying the deer tick population in the state for more than 20 years.

When she first started, in order to find them in great numbers, you had to look in the north woods. But that's not the case anymore.

"There's no spot left where we've gone looking for them and we haven't found them," she told CBS affiliate WISC.

With the spread of ticks has come the spread of Lyme disease. Twenty years ago, Paskewitz would tell her students there'd be 400 to 500 cases each year in Wisconsin.

"Now when I teach the class, it's 3,000 cases each year," she said, adding that according to the CDC, that number likely "under-estimates by quite a lot. It is probably closer to 30,000 cases in the state. So that's a large increase."

While nowhere near as prevalent, another tick-borne disease called Powassan virus carries a serious, sometimes fatal health risk.

According to the CDC, approximately 75 cases of Powassan virus have been reported over the past decade.

"So it is a rare disease. We don't see a lot of cases," Paskewitz said. "Unfortunately, it is a disease that can often have pretty severe impact. People die as a result of Powassan infection."

Dr. Jeannina Smith, an infectious disease specialist at UW Health, explains that Powassan "attacks the brain itself, causing inflammation and infections of the brain. And because of that, patients who have had this viral encepahlitis can have significant neurological problems, if they recover."

Minnesota has seen the most cases of Powassan, with 20 reports in the past 10 years. Wisconsin and New York have each had 16 cases.

"I don't think people need to be fearful of it because it is so rare, but it is out there and it is one more reason for people to do those careful tick checks at the end of the day, or try to reduce your contact with them to begin with," Paskewitz said.

Both Lyme disease and Powassan virus present with flu-like symptoms and can progress to confusion and difficulty speaking. Both infections require medical attention as soon as possible.

To prevent these and other tick-borne illnesses, the CDC recommends using tick repellents, wearing long sleeves and pants, avoiding bushy and wooded areas, and doing thorough tick checks after spending time outdoors.