Emergence of a New Pathogenic Ehrlichia Species, Wisconsin and Minnesota, 2009

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

来源：New England Journal of Medicine, 2011, 365(5): 422-429.

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 polymerase-chain-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.

• 出版日期2011-8-4