Features of human monocytic ehrlichiosis laboratory diagnostics

Abstract

Objective. Using the data obtained in Perm Region as an example, to identify the effectiveness of polymerase chain reaction (PCR) for the diagnosis of Human Monocytic Ehrlichiosis (HME) at different periods from the onset of the disease, and to determine the role of HME in the structure of infections transmitted by ixodic ticks using PCR and enzyme-linked immunosorbent assay (ELISA)
 Materials and methods. A thorough clinical and epidemiological examination of 583 patients with acute febrile diseases developed after the suction of ticks was carried out. To detect E. muris DNA, 1586 whole blood samples were examined by PCR at different periods from the onset of the disease. For the purpose of serological verification of HME, all patients were examined with ELISA for the presence of immunoglobulins M and G against E. chaffeensis.
 Results. In total, using the PCR method, ehrlichial DNA was detected in 76 (4.8 %) blood samples from 53 patients. Based on two research methods (ELISA and PCR) HME was diagnosed in 58 (9.9 %) persons, while in 50 (86.2 %) of them, the diagnosis was confirmed only by PCR. The timing of E. muris genomic material detection in the blood of patients varied from 1 to 58 days from the moment of the disease. The greatest effectiveness of PCR (up to 69.4 % of positive samples) was noted by us from the 1st to the 7th day of illness. HME was found in the form of monoinfection in 9 (15.5 %), mixed infection in 49 (84.5 %) persons. The following was revealed: HME+Ixodid tick-borne borreliosis (ITBB) in 35 (60.3 %), HME+ITBB+Human granulocytic anaplasmosis (HGA) in 6 (10.3 %), HME+ITBB+HGA+Tick-borne encephalitis (TBE) in 4 (6.9 %), HME+TBE in 2 (3.5 %), HME+TBE+ITBB in 2 (3.5 %).
 Conclusions. In the diagnosis of HME, PCR significantly increased the number (up to 86.2 %) of confirmed cases, and most often in the acute period of the disease (up to 69.4 15.3 % of positive samples in the first week of the disease). For laboratory verification of HME, it is advisable to combine ELISA with the PCR method, especially in case of negative results of serological studies.