Emergence of a new pathogenic Ehrlichia species, Wisconsin and Minnesota, 2009

Bobbi S. Pritt, Lynne M. Sloan, Diep K. Hoang Johnson, Ulrike G. Munderloh, Susan M. Paskewitz, Kristina M. McElroy, Jevon D. McFadden, Matthew J. Binnicker, David F. Neitzel, Gongping Liu, William L. Nicholson, Curtis M. Nelson, Joni J. Franson, Scott A. Martin, Scott A. Cunningham, Christopher R. Steward, Kay Bogumill, Mary E. Bjorgaard, Jeffrey P. Davis, Jennifer H. McQuistonDavid M. Warshauer, Mark P. Wilhelm, Robin Patel, Vipul A. Trivedi, Marina E. Eremeeva

Research output: Contribution to journalArticlepeer-review

217 Scopus citations


BACKGROUND: Ehrlichiosis is a clinically important, emerging zoonosis. Only Ehrlichia chaffeensis and E. ewingii have been thought to cause ehrlichiosis in humans in the United States. Patients with suspected ehrlichiosis routinely undergo testing to ensure proper diagnosis and to ascertain the cause. METHODS: We used molecular methods, culturing, and serologic testing to diagnose and ascertain the cause of cases of ehrlichiosis. RESULTS: On testing, four cases of ehrlichiosis in Minnesota or Wisconsin were found not to be from E. chaffeensis or E. ewingii and instead to be caused by a newly discovered ehrlichia species. All patients had fever, malaise, headache, and lymphopenia; three had thrombocytopenia; and two had elevated liver-enzyme levels. All recovered after receiving doxycycline treatment. At least 17 of 697 Ixodes scapularis ticks collected in Minnesota or Wisconsin were positive for the same ehrlichia species on polymerasechain- reaction testing. Genetic analyses revealed that this new ehrlichia species is closely related to E. muris. CONCLUSIONS: We report a new ehrlichia species in Minnesota and Wisconsin and provide supportive clinical, epidemiologic, culture, DNA-sequence, and vector data. Physicians need to be aware of this newly discovered close relative of E. muris to ensure appropriate testing, treatment, and regional surveillance. (Funded by the National Institutes of Health and the Centers for Disease Control and Prevention.)

Original languageEnglish (US)
Pages (from-to)422-429
Number of pages8
JournalNew England Journal of Medicine
Issue number5
StatePublished - Aug 4 2011


Dive into the research topics of 'Emergence of a new pathogenic Ehrlichia species, Wisconsin and Minnesota, 2009'. Together they form a unique fingerprint.

Cite this