Epidemiological, clinical and laboratory distinction between human granulocytic ehrlichiosis and the initial phase of tick-borne encephalitis.
OBJECTIVE
To establish epidemiological, clinical and laboratory differences between adult patients with proven acute human granulocytic ehrlichiosis (HGE) and patients with the initial phase of tick-borne encephalitis (TBE).


METHODS
Epidemiological, clinical and laboratory findings were compared in nine patients with acute HGE (established by the presence of specific DNA sequences of Ehrlichia phagocytophila in whole blood by polymerase chain reaction and/or by seroconversion or at least a four-fold change of serum antibody titres to E. phagocytophila by indirect immunofluorescence assay) and 29 patients with the initial phase of TBE (demonstrated in ELISA tests by the presence of serum IgM antibodies to TBE virus).


RESULTS
Findings were similar for the majority of the general parameters examined, which included sex, age, incubation period, duration of fever, and frequency of additional tick bites. However, a statistically significant difference was found for the duration of fever before the first visit (median 7 days in patients with acute HGE and 4 days in patients with the initial phase of TBE; p = 0.0169), and for the frequency of hospitalisation, which was higher for patients with the initial phase of TBE (29/29) than for those with acute HGE (5/9; p = 0.0017). Comparison of clinical signs and symptoms and laboratory findings in the two groups revealed significant differences: in patients with acute HGE there was a higher frequency of chills (4/9 versus 3/29, respectively; p = 0.0407), myalgia (8/9 versus 13/29, respectively; p = 0.0263), and arthralgia (7/9 versus 3/29, respectively; p = 0.0003), and elevated values of lactate dehydrogenase (7/9 versus 3/29, respectively; p = 0.0003) and concentration of C-reactive protein (9/9 versus 6/29, respectively; p = 0.0000).


CONCLUSIONS
In a patient with febrile illness occurring after a tick bite, a clinical report of chills, myalgia and arthralgia, and laboratory findings of elevated values for lactate dehydrogenase and concentration of C-reactive protein direct towards a diagnosis of acute HGE rather than the initial phase of TBE.
Lotric-Furlan
Stanka
S
Department of Infectious Diseases, University Medical Centre, Ljubljana, Slovenia. stanka.lotric-furlan@mf.uni-lj.si
Petrovec
Miroslav
M
Avsic-Zupanc
Tatjana
T
Logar
Mateja
M
Strle
Franc
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D041081:Anaplasma phagocytophilum / Q000235:genetics; D000818:Animals; D001733:Bites and Stings / Q000150:complications; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D016873:Ehrlichiosis / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D004675:Encephalitis, Tick-Borne / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008875:Middle Aged; D010343:Patient Admission / Q000706:statistics & numerical data; D016133:Polymerase Chain Reaction; D012698:Serologic Tests; D017524:Slovenia; D013987:Ticks