UND researchers study long-term symptoms of tick-borne illness
Long hikes through the Upper Midwest are an excellent way to take in the landscape. They're also a pretty good way to pick up ticks.
The small parasites are usually just a minor inconvenience to pry off. But in 2015, that small bite led to Lyme disease in at least 1,176 confirmed cases in Minnesota and 33 in North Dakota. Though the Minnesota forests have been known to harbor Lyme disease for some time, the westward spread is a more recent phenomenon.
"Ten years ago, nobody thought there was Lyme disease in North Dakota" said UND medical science researcher Catherine A. Brissette.
Since then, she said, tick surveys and confirmed cases as far as the state's Montana border have ended that notion by revealing the presence of Borrelia burgdorferi, a tick-dwelling bacteria which causes Lyme disease.
"We've isolated these bacteria from small mammals here in the Grand Forks area and showed that, yes, they're here, they're infectious," Brissette said. "And in the state, we found an increase in cases of Lyme disease in last several years, so it's definitely moving into this region."
Lyme disease can usually be treated with a battery of antibiotics taken over a few weeks. However, for some infected with the disease, symptoms such as fatigue, pain, or joint and muscle aches can stretch into a longer-term illness known as Post-Treatment Lyme Disease Syndrome.
Brissette and a group of UND School of Medicine and Health Science researchers, including fellow professors and medical scientists Archana Dhasarathy and John Watt, are now spearheading a study aimed at determining how symptoms can persist in patients who should ostensibly be cured. The group's efforts were recently awarded a $108,000 grant from the Global Lyme Alliance, for which Brissette serves on an advisory board.
The funded study is intended to build a better understanding of persistent brain inflammation, a prominent feature of Lyme disease.
Brissette said early research indicates that infection by Borrelia bacteria can lead to changes in the epigenetics—a kind of informational supplement to DNA which helps translate genetic code into actual characteristics—of specialized cells in the human brain.
Those cells, known as astrocytes, play an important support role in the blood-brain barrier, a structure that coats the brain and acts as a sort of molecular bouncer, regulating the movement of nutrients and other substances into the brain. The astrocytes are also thought to conduct some cellular-level maintenance and repair.
Probing at the mechanisms of PTLDS called for a cross-discipline approach in the SMHS Department of Biomedical Sciences. Brissette's research mainly focuses on spiral-shaped bacteria, a group which includes the germ which causes Lyme disease. Dhasarathy brings a speciality in epigenetics. Watt's expertise rests with astrocytes.
The question of the exact nature of the epigenetic shift in those brain cells—and how the bacteria might cause it—rests at the center of the UND study.
"We know there are these changes taking place, so now we're trying to find exactly what those are," said Brissette.
The first step of the grant process is dedicated to producing those kinds of findings. Once the epigenetic processes are more clear, Brissette said the research team will shift to studying how the neuroinflammatory symptoms of PTLDS can be better treated in the future.