Move over mosquitoes: Tick-borne diseases on the rise in Minn.

Published 10:55 am Wednesday, May 11, 2011

Living in Mower County, it’s easy to forget about ticks and the potential diseases they can carry. But tick-borne diseases reached record-high levels in 2010, and health officials say they’re still on the rise.

Jeanine Vorland, Department of Natural Resources area wildlife manager said, “We do now live where it is, so we should be aware of it.”

She and others nearby have encountered many ticks. One of her friend’s dogs recently contracted Lyme disease in Freeborn County.

Email newsletter signup

Minnesota’s three most common tick-borne diseases come from the blacklegged tick, often called the deer tick. According to a news release from Minnesota Department of Health (MDH), the three most common tick diseases, Lyme disease, Babesiosis and anaplasmosis, all increased in 2010.

The one that has officials concerned is human anaplasmosis, which researchers didn’t discover until the mid-1990s. About 30 percent of the 2010 anaplasmosis patients were hospitalized, and one patient died. Some central Minnesota counties recorded higher numbers of anaplasmosis than Lyme disease, too.

“We’re seeing a continuing and troubling trend of marked increases in cases of tick-borne diseases in Minnesota,” said Dave Neitzel, MDH epidemiologist specializing in the area. “We are particularly concerned about anaplasmosis, with case numbers now rivaling Lyme disease in some areas of the state.”

In Mower County, the problem may not be that severe, as most of the diseases come from the deer tick, which can’t survive outside heavily wooded areas.

“The ticks have a lot harder time trying to survive,” Neitzel said. “They’re not going to survive in corn.”

Neitzel added, “It all comes down to what the ticks feed on.” The deer tick feeds on the blood of white-footed mice and chipmunks, from which it contracts the diseases.

But everyone should watch out. Neitzel said anaplasmosis, among other deer tick diseases, can cause fever, chills and muscle aches. Anyone experiencing these symptoms during the summer should seek medical attention, as that is unusual.

Neitzel said part of the rise in numbers may be more awareness and better medical findings. But he’s still concerned ticks and their diseases are spreading.

“We’re seeing increases in all of our tick diseases,” he said.

Cases of other serious but less common diseases carried by ticks in Minnesota have also increased in number. “We’re concerned about new cases of tick-borne diseases that hadn’t been detected in Minnesota before 2008,” Neitzel said. These newer diseases include Powassan virus disease and a new form of ehrlichiosis, both of which appear to be carried by the blacklegged tick. A different form of ehrlichiosis, as well as Rocky Mountain spotted fever and tularemia, are also occasionally found in Minnesota residents.

All forms of tick diseases can be treated with antibiotics except for Powassan, as it is caused by a virus. About 30 percent of the 2010 anaplasmosis patients were hospitalized, and one patient died. Nearly half of the babesiosis cases were hospitalized, and one patient died, as well.

Although the diseases can be severe, Neitzel said prevention can be easy. He studies ticks in heavily wooded areas finds about 200 to 300 on his skin each year. Through all his encounters, he’s never contracted a disease from a tick.

For deer ticks, the best approach is repellent because young deer ticks can be nearly impossible to spot. They look like tiny black spots.

“The challenge is the small, nymph stage of the tick,” he said.

So officials recommend either 30 percent DEET-based repellent or Permethrin-based repellents.

People who find deer ticks on themselves are usually still okay, however. Deer ticks must attach themselves to the skin for more than a day to transmit any disease. Prevention and paying attention to skin is the best approach.

2010 Deer tick diseases

• Lyme disease: 1,293, up 21 percent from 2009 and slightly above the 2007 level of 1,239.
• Human anaplasmosis: 720 (more than double the 300-plus cases in recent years).
• Babesiosis: 56, up from 31 in 2009.

Other diseases ticks can carry:

• Powassan virus disease
• Different forms of ehrlichiosis
• Rocky Mountain spotted fever
• Tularemia