Infectious Diseases

The etiological structure and specificities of the current course of Ixodes tick-borne borrelioses in the Chelyabinsk region

The article presents a molecular-epidemiological analysis of the causative agents of Ixodes tick-borne borreliosis in natural foci of the Southern Ural, offers a comparative clinical and etiopathogenetic characteristic of various forms of disease. Monitoring of the genetic structure of ITB pathogens in natural foci of Southern Urals has shown that the spirochetes B. garinii and B. afzelii are practically ubiquitous and circulate together. The genospecies B. garinii is represented by two types: 20047т and NT29. The range of bacterial load in ticks Ix. persulcatus was studied, which amounted to 101–106 copies of Borrelia DNA in a tick. In 76.5% of ticks, low bacterial load was observed with threshold cycles above 35. The etiological structure of ITB is monoinfection (73.7%), incl. caused by B. afzelii in 10 patients (16.4%), B. garinii – in 25 patients (40.9%) and B. burgdorferi s.s. – in 10 patients (16.4%). A marked clinical polymorphism and a significantly high incidence of organ pathology syndrome with signs of damage of the nervous, cardiovascular systems and locomotor apparatus were noted (50, 25,1 and 12.6%, respectively). In 34.5% of patients, combined pathology can be found, in 30.3% – isolated damage of the nervous system (neuroborreliosis). The main manifestations of neuroborreliosis were serous meningitis, meningoencephalitis, meningoradiculoneuritis, neuropathy of the facial nerve, radiculoneuritis, encephalomyelitis. We have found a significant probability of the formation of stable neurological residual events (impaired cognitive functions, depressive episode – 13.8%) in nonerythemic
forms of ITB.
Key words: Borrelia genospecies, diagnosis, Ixodes-tick borrelioses, clinical signs, pathogenesis.
For citation: Konkova-Reidman A.B., Barsukova D.N. The etiological structure and specificities of the current course of Ixodes tick-borne borrelioses in the Chelyabinsk region. Infekc. bolezni (Infectious diseases). 2019; 17(2): 32–39. (In Russian).

DOI: 10.20953/1729-9225-2019-2-32-39