title: Differences and similarities between culture-confirmed human granulocytic anaplasmosis and early lyme disease.
abstract: Lyme disease is transmitted by the bite of certain Ixodes ticks, which can also transmit Anaplasma phagocytophilum, the cause of human granulocytic anaplasmosis (HGA). Although culture can be used to identify patients infected with A. phagocytophilum and is the microbiologic gold standard, few studies have evaluated culture-confirmed patients with HGA. We conducted a prospective study in which blood culture was used to detect HGA infection in patients with a compatible clinical illness. Early Lyme disease was defined by the presence of erythema migrans. The epidemiologic, clinical, and laboratory features of 44 patients with culture-confirmed HGA were compared with those of a convenience sample of 62 patients with early Lyme disease. Coinfected patients were excluded. Patients with HGA had more symptoms (P = 0.003) and had a higher body temperature on presentation (P < 0.001) than patients with early Lyme disease. HGA patients were also more likely to have a headache, dizziness, myalgias, abdominal pain, anorexia, leukopenia, lymphopenia, thrombocytopenia, or elevated liver enzymes. A direct correlation between the number of symptoms and the duration of illness at time of presentation (rho = 0.389, P = 0.009) was observed for HGA patients but not for patients with Lyme disease. In conclusion, although there are overlapping features, culture-confirmed HGA is a more severe illness than early Lyme disease.
authors.affiliation: Department of Medicine, Division of Infectious Diseases, New York Medical College, Valhalla, New York, USA. gary_wormser@nymc.edu
authors.forename: Gary P
authors.initials: GP
authors.lastname: Wormser
authors.forename: Maria E
authors.initials: ME
authors.lastname: Aguero-Rosenfeld
authors.forename: Mary E
authors.initials: ME
authors.lastname: Cox
authors.forename: John
authors.initials: J
authors.lastname: Nowakowski
authors.forename: Robert B
authors.initials: RB
authors.lastname: Nadelman
authors.forename: Diane
authors.initials: D
authors.lastname: Holmgren
authors.forename: Donna
authors.initials: D
authors.lastname: McKenna
authors.forename: Susan
authors.initials: S
authors.lastname: Bittker
authors.forename: Lois
authors.initials: L
authors.lastname: Zentmaier
authors.forename: Denise
authors.initials: D
authors.lastname: Cooper
authors.forename: Dionysios
authors.initials: D
authors.lastname: Liveris
authors.forename: Ira
authors.initials: I
authors.lastname: Schwartz
authors.forename: Harold W
authors.initials: HW
authors.lastname: Horowitz
mesh_terms: D000328:Adult; D000368:Aged; D041081:Anaplasma phagocytophilum / Q000302:isolation & purification*; D000712:Anaplasmosis / Q000175:diagnosis* / Q000473:pathology*; D000818:Animals; D001769:Blood / Q000382:microbiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008193:Lyme Disease / Q000175:diagnosis* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies