Clinical and epidemiologic assessment of results of testing individuals and Ixodes ticks for etiologic agent of human ehrlichiosis in mixt endemic sites of tick-borne infections in the Tomsk Region
AbstractEhrlichiosis is a group of acute tick-borne zoonosis including human monocytotropic ehrlichiosis (HME) and human granulocytotropic anaplasmosis (HGA), which characterized by polymorphic clinical symptoms.
The objective of the study is to assess incidence disease rates of HME and HGA in the spectrum of tickborne infections in the Tomsk Region for the first time.
We have tested 1120 samples of Ixodes ticks picked in various natural biotopes of the Tomsk Region for Ehrlichia and Anaplasma by PCR. Moreover, from 2004 to 2013, about 6712 human serum samples obtained from residents of Tomsk and the Tomsk Region are assessed for specific antibodies to Ehrlichia and Anaplasma by ELISA. Clinical symptoms are analyzed in 30 patients of HME and 64 patients of HGA.
It is found that from 2,5 to 10 % ticks picked in various natural biotopes of the Tomsk Region are infected with Ehrlichia. Contamination of Ixodes ticks with Anaplasma are varied from 3,1 до 10,6 %. Altogether we have registered 141 human clinical cases including 104 (73,7 %) patients with HGA (incidence rates varied from 0,19 to 4,7 per 100 000 population) and 37 (26,3 %) patients with HME (incidence rates varied from 0 to 1,64 per 100 000 population). Clinical symptoms in patients with HME and HGA are very much alike, excluding skin eruption and lymphadenitis, which are significantly more frequent in HME (p<0,05) and leukopenia predominantly associated with HGA (p<0,05).
Thus, we first establish higher risk of HME and HGA infections for population in the Tomsk Region.
Keywords:human granulocytotropic anaplasmosis, HGA, human monocytotropic ehrlichiosis, НМЕ, tick-borne infections, clinical symptoms, enzyme-linked immunosorbent assay, ELISA, incidence rates, IR, polymerase chain reaction, PCR, Tomsk Region