Photo by Mayo Foundation for Medical Education and Research
Pritt the Lab Worker
Bobbi Pritt has decorated her office at the Mayo Clinic with ticks and parasites—none currently alive, at least not that she knows—in a conspicuously cheerful style. If that characterization seems impossible, then you’ve probably never seen a football-sized plush tick—or met Bobbi Pritt. On a recent day just before tick season, she shows off the stuffie, grabbing it with a pair of tweezers the size of a fire hydrant.
“To remove a giant tick you need a giant forceps,” she says.
Pritt turns to a DIY project, a plastic disc on her desk that showcases blacklegged ticks at different stages of engorgement.
“This is my latest arts-and-crafts project,” says the parasitologist and one-time art major. “They sell these for making jewelry.”
Other favorite projects include an annual calendar of artistic close-up photos of parasites, insects, and ticks (you can order one online, though she doesn’t make a profit from it), and cell phone cases featuring magnified images of tapeworms and head-lice nits (they’re abstract enough, she admits, that they could be mistaken for a new Kate Spade style).
Pritt’s public reputation stems largely from a blog she started in 2007, called Creepy Dreadful Wonderful Parasites. Each week, she posts a mystery medical case involving an unidentified parasite: Unsolved Mysteries, where the offender is a malicious parasite. Readers write in to guess the perp. Upon being introduced to her at meetings, people will often say, “Hey! You’re Parasite Gal!”
With five or six or seven research projects going on at once, Pritt feels fortunate that she is able to mix business and pleasure—especially after the snow has melted and tick season begins. This is showtime for a parasitologist, and anxiety tends to creep into her daily life.
“I’ll be driving along and see a beautiful field of flowers,” Pritt says. “And now I think, ‘I wouldn’t want to walk through that without insect repellent—just think of all the ticks!’ Whereas maybe 10 years ago, I would’ve just thought, ‘What a beautiful field of flowers.’”
Growing up in Vermont, Pritt lived a tick-free childhood. Since then, as ticks continue to expand their range, Vermont has joined the Northeast’s tick hotbed. Tick territory continues to increase rapidly: A new federal health study ranked Minnesota number seven for tick-based infections. Even within Minnesota, blacklegged ticks now show up further west and north. And Pritt is bracing for the eventual local arrival of the Lone Star tick, one of the species known to harbor diseases. For the macabre or the masochistic, something to look forward to.
The Lone Star tick is a vector for ehrlichiosis: a potentially deadly bacterial disease. The blacklegged tick (a re-branding effort for the pest previously known as the “deer tick”) harbors Lyme disease, the most prevalent tick-borne disease. It affects more than 300,000 Americans every year. In Minnesota, babesiosis (treatable, but life-threatening to some) and anaplasmosis (also life-threatening if untreated) represent the most common tick-borne diseases after Lyme disease. Elsewhere in the country—if you’d prefer a more unusual infection—there’s Southern Tick-Associated Rash Illness, Tick-Borne Relapsing Fever, and tularemia.
In some cases, ticks aren’t born with these diseases; they pick them up from feeding on other animals, usually small rodents. This is where Pritt’s lab comes in. All year long, the team tests blood samples from patients with suspected tick-borne diseases to identify the pathogens making people sick.
“If we know they are out there, in ticks and wildlife, we can do studies to see how common they are and learn how to prevent infection with them,” Pritt says.
If the lab identifies a new cause for disease, scientists can then develop tests to determine if a patient’s blood contains a specific pathogen. It’s an early step toward the ultimate goal of developing new drugs and treatments.
Already, Pritt’s lab has helped reveal two unknown bacteria that appear to cause tick-borne diseases. In 2012, for example, a tech noticed an anomaly in a blood sample from a patient suspected to have Lyme disease. He flagged it, and the team found six more samples from patients. Working with the Centers for Disease Control and Prevention and state health departments, they confirmed it as a previously unknown bacterium that appears to cause Lyme disease in the U.S.—just the second of its kind. Pritt’s lab named it Borrelia mayonii, after the Mayo brothers, who founded the Mayo Clinic. An unexpected honor, no doubt.
That discovery spurred the partnership to look for more. So far, Pritt’s lab has sent more than 10,000 patient samples to the CDC. Recently, the CDC typed a bacterium that had previously been found only in bat ticks, not in people. Scientists work to unpack the significance of that finding as part of a (much larger) quest to understand and prevent tick-borne diseases.
That work has a way of following Pritt home. Her cabin in Wisconsin happens to lie in the middle of tick country. “I really didn’t plan that,” she says. “It’s funny because part of me wants to just relax while I’m there, but part of me wants to go look for ticks.”
Her compromise? She invites folks from the CDC to join her for tick-dragging parties. Looking for ticks involves dragging white flannel through brushy tick habitat. Often, what look like tiny specks of dirt on the fabric turn out to be ticks.
“We’ll do a full day of dragging, and then we’ll have a cookout and play Bananagrams,” she says.
NO BITING!
Many types of ticks make a happy home in Minnesota, but two in particular pose threats to humans. To reduce your risks of contracting a disease, cover your skin fully when hiking in tick habitat. That means tucking pants into socks (stylish!) and wearing long-sleeved shirts and hats. White clothing (it’s after Easter) renders ticks easier to see and remove. Even better, spray all your clothing with a product containing permethrin. And spritz exposed skin with an insect repellent containing deet, picaridin, or lemon eucalyptus oil. Finally, a shower after your hike will increase the odds that you’ll find any ticks that managed to sneak through.
If you do find a tick, remove it with forceps or tweezers, pinching it by the head. Submerge the tick in alcohol, wrap it in tape, or flush it down the toilet (a fitting burial at sea).
MEET THE ENEMY
Photo courtesy of the CDC/James Gathany
black legged tick deer-tick
Ixodes scapularis
(blacklegged tick/deer tick)
Favored host: Small rodents, especially the white-footed mouse, deer . . . and you.
My hangout: I’ll find a long blade of grass to climb on, extend my legs, and wait for you to walk by. (Entomologists call this behavior “questing.”)
Size: Poppy seed (nymphs) to sesame seed (adult). Swells to the size of a poop emoji when engorged with blood.
I’d like to give you something special! Lyme disease, babesiosis, anaplasmosis, Powassan virus disease, and Borrelia miyamotoi relapsing fever.
Dermacentor variabilis
Photo courtesy of the CDC/james Gathany
Dermacentor variabilis
(American dog tick/wood tick)
Favored host: Raccoons, skunks, opossums and coyotes, pet dogs and cats . . .and you!
Where I lurk: Grassy fields, trails, and walkways with no tree cover. Exactly where you like to hike.
Superpower: Females can lay more than 4,000 eggs.
Size: Sesame seed (nymph) and apple seed (adult).
I’d like to give you something special! I can carry bacteria that cause Rocky Mountain spotted fever and tularemia.
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