ST. PAUL, Minn. (AP) -- Minnesota residents may believe this past winter was rough, but state health officials say it wasn't bad enough to kill off the deer ticks that carry Lyme disease.

Dave Neitzel is an epidemiologist with the Minnesota Department of Health. Neitzel says the cold kills ticks only if the insects are exposed to the air. He says the ticks mostly survived the harsh cold by staying insulated under a thick blanket of snow.

Early results from health department field surveys indicate there are more deer ticks now compared to this time last year.

Deer ticks carry Lyme disease, which causes fever and fatigue, joint damage and, if left untreated, heart and neurological problems.

Neitzel urges outdoor enthusiasts to protect themselves from tick bites with repellents containing DEET or permethrin.

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