Tick Dragging with Bobbi Pritt, M.D.
Minnesota Department of Health researchers recently teamed up with scientists from Mayo Clinic for a “tick drag” at Camp Ripley in Minnesota. During the drag, they gather samples to bring back to their labs to add to surveillance records and test for disease pathogens, both of which help determine the risk that black-legged ticks pose to people.
One of those scientists from Mayo Clinic was Bobbi Pritt, M.D., Director of the Clinical Parasitology Lab and Co-Director of Vector-Borne Diseases Lab Services in Mayo Clinic’s Department of Lab Medicine and Pathology. During the tick drag, Dr. Pritt told the Washington Post, “I have to be really careful because the nymphs, being the size of a poppy seed, can look like just little dots. But then you look at them and they move—or they have little legs.”
According to the article, Borrelia burgdorferi, the main bacterium that causes Lyme disease, is found in about 40% of adult ticks and 20% of nymphs, although researchers have found rates vary drastically by location. But the CDC report noted that nine new mosquito- and tick-borne germs have been discovered or introduced since 2004, including two discovered by Dr. Pritt’s lab that have been found only in the Upper Midwest. Those localized pathogens fall into a category of “non-notifiable” diseases that the CDC doesn’t track but that could affect people.
“I wouldn’t be surprised if more [localized pathogens] continue to be discovered,” says Dr. Pritt, possibly explaining cases where people are sick but no one knows why. “Those are the cases that particularly interest me,” Dr. Pritt says. “A lot of my work is involved with trying to figure out what else is out there.”
After returning to her Rochester lab, Dr. Pritt tests the ticks from the Camp Ripley drag for Powassan virus in addition to looking for the bacteria that cause Lyme, Ehrlichiosis, babesiosis, anaplasmosis and tick-borne relapsing fever. The Powassan virus, while rare, can be deadly. But Dr. Pritt suspects there are more patients who have a milder form of the disease. Dr. Pritt is developing a test for it; she was hoping to use some of the ticks from the drag in that work, but none tested positive for the virus.