Assistant professor Catherine Brisette. Photo via med.und.edu.

Scientists at UND warn that all the variables for contracting Lyme disease are now present and established in Grand Forks County.

Although North Dakota borders Minnesota counties, where the risk of contracting the tick-borne Lyme disease is moderate to high based on confirmed human cases, few studies have been done on the migration of the disease farther west.

A joint research team led by biology professor Jefferson Vaughan and assistant professor Catherine Brissette, a biomedical scientist in the Department of Basic Sciences at the School of Medicine and Health Sciences, reports it has verified that Lyme disease has spread to Grand Forks County. Brissette’s laboratory works on the causative agent of Lyme disease, the bacterium Borrelia burgdorferi.

“Jeff Vaughan’s student, Nate Russart, a UND graduate student in biology, was surveying ticks and tick-borne pathogens across the state of North Dakota,” Brissette said.“This suggested that the Lyme disease bacterium was in our area. But it didn’t prove that getting bitten by one of these ticks would transmit the Lyme disease bacterium. We wondered if we could isolate live B. burgdorferi bacteria from those local mice or voles.”

Lyme borreliosis, commonly referred to as Lyme disease, is an infectious disease caused by the bite of an infected tick. Brissette explained the process used to identify the disease.

“We were able to isolate live B. burgdorferi from the hearts of mice and voles from the Forest River and Turtle River areas of Grand Forks County,” Brissette said. “We showed that these bacteria were indeed the Lyme disease bacterium. We were also able to show that these bacteria were related closely to B. burgdorferi from Minnesota, Wisconsin, and eastern Manitoba, demonstrating that B. burgdorferi has migrated westward.”

Next the research team tested the ability of these bacteria to transmit disease. In nature, female ticks feed on deer and then lay their eggs. When the eggs hatch, the larval ticks do not carry the Lyme disease bacterium.

The larval ticks only become infected if they feed on an infected animal; usually a mouse or other small rodent. These ticks will feed and then molt to the next life stage called a nymph. Infected nymphs can then transmit the infection to another small mammal, maintaining the bacterium in the environment. The nymphs can feed on an end host such as a person or pet. To test and prove that local bacteria were infectious, the research team looked at each stage of the infectious cycle in the laboratory.

“Prevention is key,” Brissette said. “The ticks are very small, the size of a poppy seed. The tick has to feed for at least 24 hours before it can transmit the Lyme disease bacterium, so it’s important to check yourself carefully for ticks after being in the woods. Wearing long sleeves and pants can help, as well as using repellents that contain DEET.”

Early symptoms may include fever, headache and fatigue. A rash occurs in about 70 to 80 percent of infected persons at the site of the bite after a delay of three to 30 days. The rash is rarely painful or itchy, although it may be warm to the touch. About 20 to 30 percent of infected persons do not experience a rash. Left untreated, later symptoms may involve the joints, heart and central nervous system. In most cases, antibiotics eliminate the infection and its symptoms, especially if the illness is treated early. Delayed or inadequate treatment can lead to more serious symptoms, which can be disabling and difficult to treat.

For future research, Vaughan is interested in whether voles might be an important reservoir in our area for the Lyme disease bacterium. Brissette is interested in what other bacteria or viruses these ticks might carry, and how that influences the transmission of disease.

Colin Johnson is a staff writer for The Dakota Student. She can be reached at [email protected].