Discovery of new tick-borne bacterium
Research helps educate public, physicians
Carol Werner, a Mayo Clinic Health System technologist in Eau Claire, Wis., noticed an anomaly in a blood sample and spoke up. Because she raised a red flag, Mayo Clinic began an investigation with the Centers for Disease Control and Prevention, area universities and several public health departments.
Tick-borne bacterium newly present in Minnesota and Wisconsin
The investigation revealed that a tick-borne bacterium, which infects humans with ehrlichiosis, is newly present in Minnesota and Wisconsin. Increasing reports of ehrlichiosis in humans led the Minnesota Department of Health to put out a health advisory in 2010.
The new bacterium, which has not yet been named, is a member of the ehrlichia genus and can cause a fever and other symptoms. DNA testing and culture analyses were conducted at Mayo Clinic to confirm the new strain, and the resulting research earned a spot in the Aug. 4, 2011, edition of the New England Journal of Medicine.
New awareness spreads to physicians and outdoor enthusiasts
"Before this report, human ehrlichiosis was thought to be very rare or absent in Minnesota and Wisconsin," says Bobbi Pritt, M.D., a Mayo Clinic microbiologist and director of the Clinical Parasitology and Virology Laboratories who helped coordinate the multi-agency research team. "Physicians might not know to look for ehrlichia infections at all."
The bacterium is likely transmitted through the bite of infected ticks, which are most active in the spring and summer months. Publication of the research in the New England Journal of Medicine, propelled Mayo Clinic and the other research partners to raise awareness about tick-borne illnesses and educate the states' outdoor sports enthusiasts about applying insect repellent and wearing pants and long-sleeved shirts when active outdoors.
Early recognition of symptoms aids in healthcare delivery
Ehrlichia infect and kill white blood cells and may cause fever, body aches, headache and fatigue. More severe cases may involve multiple organs such as the lungs, kidneys and brain and require hospitalization, but ehrlichiosis rarely results in death.
"As the deer tick population continues to spread and increase across Wisconsin, we are likely to see increasing incidence of this new infection, just as we have seen with Lyme disease and anaplasmosis which are transmitted by the same tick species,'' says Susan Paskewitz, Ph.D., an entomologist at the University of Wisconsin-Madison and co-author of the New England Journal of Medicine article.
Mayo Clinic aids in screening of blood samples nationwide
Thousands of blood samples from across the United States have been screened by Mayo Clinic laboratory technologists, and the bacterium has been detected only in specimens collected from Wisconsin and Minnesota. Thousands of ticks across the country have also been analyzed, and only those from the two states have been carriers. This suggests that the newly discovered bacteria is geographically restricted to the upper Midwest.
Traditional blood antibody tests may offer misleading results and fail to accurately identify the new species. A specific antibody test for the new bacterium has been developed by the CDC but it isn't widely available yet. Instead, a molecular blood test that detects DNA from the new ehrlichia species is the preferred method for detecting this disease in symptomatic patients.