723 blood sera from 537 patients of Regional Infectious Clinical Hospital, Astrakhan were obtained during high activity period of Rhipicephalus ticks (May-September 2015) and retrospectively studied for IgG/IgM to antigen of spotted fever group (SFG) Rickettsia. IgG and/or IgM to Rickettsia conorii were detected in 145 sera from 130 patients, and antibodies to R. sibirica (group-specific) were detected in 143 sera from 145. Antibodies to R. conorii were detected for 71,4% patients with Astrakhan spotted fever (ASF), for 28,4% patients with acute respiratory viral infection, for 19,1% patients with infection of unspecified etiology and for 40% patients having symptoms of a adenovirus infection. Acute rickettsiosis, provably ASF, is serologically validated for 71 patients. Dynamic of IgM/IgG to R. conorii in sera of patients having different preliminary diagnoses is discussed. IgM to R. conorii in sera of patients having adenovirus infection symptoms were detected at a later time as compared with others. For regions of high risk of R. conorii subsp. caspia infection the differentiation of diagnostic and anamnestic specific antibodies is very important. The absence of serological and molecular biological markers in third of patients with ASF symptoms is necessary to study. Preparations and algorithms for diagnosis of SFG rickettsioses are needed to improve.

Relevance. The Sverdlovsk district is a tense natural focus for Lyme borreliosis (LB) with a constantly recorded incidence that exceeds these indicators in the Russian Federation and the Ural Federal region several times. LB is registered on 56 of 59 administrative territories of the district. Currently, the count of LB in the Russian Federation includes both infections caused by Borrelia burgdorferi sensu lato group Borrelia and infections caused by Borrelia miyamotoi sensu lato group Borrelia.Aim. To characterize the epidemic process of LB in the territory of the Sverdlovsk district over a 20-year period (2002–2021).Materials and methods. The paper uses data from federal and regional statistical observations, reporting materials of the Department of Rospotrebnadzor in the Sverdlovsk district for 2002–2021, methods of statistical analysis.Results and discussion. During the follow–up period (2002–2021), the incidence rate of BL in the Sverdlovsk district exceeded the average long-term level in the Russian Federation by almost 3 times, and in the Ural Federal region – by 1.8 times. Among the mechanisms and ways of transmission of LB pathogens, the vector-borne mechanism dominated (84.5%), the share of the unidentified pathway was 15.4%, alimentary (when using raw goat's milk) – 0.1%. The duration of the epidemic season for LB in the district was 10 months (from March to December) with a peak incidence in June. Cases of LB were registered among people of different ages, with a predominance in the group of 60 years and older (39.1%). An analysis of the distribution of people with LB by social composition showed that pensioners prevailed among them – 36.3%, officials made up 27.8%, unemployed – 14.1%. Among the cases, a high proportion of schoolchildren and children under 7 years old were noted. It was found that erythematous and non-erythematous forms of LB are registered in the district, with a predominance of erythematous (64.5%). The main etiological agent of the erythematous form is Borrelia garinii, while the non-erythematous form is Borrelia miyamotoi and B. garinii. In the general structure of morbidity, the number of cases of LB is largely determined by the city inhabitants (92.9%). There were no fatal outcomes in LB in the territory of the district during the studied period.Conclusions. Due to the lack of vaccination of LB worldwide, the only strategy to reduce the incidence of LB is non-specific prevention and timely diagnosis of the disease, including data from epidemiological history, clinical and laboratory diagnostics. The long-term clinical and epidemiological and laboratory studies conducted by us in the Sverdlovsk district allowed us to characterize the main manifestations of the epidemic process of LB and to improve the diagnosis of the disease.

The article discusses the results of a retrospective study for the presence of Coxiellosis serological markers in 723 blood sera from 537 febrile patients hospitalized in May-September 2015 in the regional infectious hospital in the Astrakhan region. Blood sera were screened by ELISA for the presence of IgG and IgM to II phase Coxiella burnetii (IgG II and IgM II, respectively). Samples, containing IgG II, wear detected IgG to I phase C. burnetii (IgG I). 92 seropositive C. burnetii patients (including 15 children’s) were identified. Characteristics of the antibody profiles in this study (IgG II, IgG II + IgM II, IgG II + IgG I, IgG II + IgM II + IgG I, IgM II) and their titers were given. The clinical picture is typical for acute infectious diseases was more often noted (diagnoses - acute respiratory disease / acute respiratory viral infection, adenovirus infection, Astrakhan spotted fever, coxiellosis) at spectrum detecting IgM II, IgM II + IgG II or IgG II (1: 800-1: 1600 titters). The «unknown etiology viral infection» diagnosis was more common among adults with any possible antibodies spectrum. Diagnostic criteria of acute Q fever and chronic coxsiellosis are discussed in the context of the serological testing results.

The article discusses the results of a retrospective study for the presence of Coxiellosis serological markers in 723 blood sera from 537 febrile patients hospitalized in May-September 2015 in the regional infectious hospital in the Astrakhan region. Blood sera were screened by ELISA for the presence of IgG and IgM to II phase Coxiella burnetii (IgG II and IgM II, respectively). Samples, containing IgG II, wear detected IgG to I phase C. burnetii (IgG I). 92 seropositive C. burnetii patients (including 15 children’s) were identified. Characteristics of the antibody profiles in this study (IgG II, IgG II + IgM II, IgG II + IgG I, IgG II + IgM II + IgG I, IgM II) and their titers were given. The clinical picture is typical for acute infectious diseases was more often noted (diagnoses - acute respiratory disease / acute respiratory viral infection, adenovirus infection, Astrakhan spotted fever, coxiellosis) at spectrum detecting IgM II, IgM II + IgG II or IgG II (1: 800-1: 1600 titters). The «unknown etiology viral infection» diagnosis was more common among adults with any possible antibodies spectrum. Diagnostic criteria of acute Q fever and chronic coxsiellosis are discussed in the context of the serological testing results.

Relevance. The Sverdlovsk region is a highly endemic territory for infections transmitted by ixodic ticks. The possibilities of laboratory diagnostics of tick–borne infections in the routine practice of a clinician in the region today are limited mainly by testing blood serum for antibodies to the tick-borne encephalitis virus (TBE virus) and Lyme disease (LD) pathogens – Borrelia burgdorferi sensu lato complex, therefore, among tick-borne infections in the region currently mainly TBE and LD are registered. In case of negative results for antibodies to the pathogens of the above infections, the diagnosis may remain unknown. Aims. To study the etiological structure of infections transmitted by ixodic ticks in the Sverdlovsk region at the present stage, as well as to characterize the epidemiological and clinical features of the course of tick-borne infections detected in conditions of a combination of natural foci. Materials and methods. The study included 227 patients undergoing inpatient or outpatient treatment during the epidemic season of tick activity in 2021 (June-August) at LLS MO "New Hospital" (Urban Center of Natural Focal Infections). The case histories (epidemiological, clinical and laboratory indicators) were studied from each patient, as well as the material (blood) was examined prospectively and retrospectively using molecular biological (PCR) and serological (ELISA, planar protein biochip) methods. Results and discussion. During the study, six diseases were identified among the examined patients: TBE, LD (erythematous and nonerythematous forms), Borrelia miyamotoi disease (BMD), human granulocytic anaplasmosis (HGA), human monocytic ehrlichiosis (HME), as well as "Viral fever transmitted by arthropods" (VFTA). Among the examined patients, the proportion of patients with monoinfection was 49,5%, with mixed infection – 50,5%. Additional studies conducted by us using specific PCR for the presence DNA rickettsia and the causative agent of Q-fever in the blood of patients gave negative results. The general epidemiological characteristics for the above identified infections were the vector-borne mechanism, the prevalence of diseases in groups of middle-aged and elderly people, the largest number of cases of infection with pathogens of any tick-borne infection occurred in Yekaterinburg and its surroundings, for all infections, the duration of tick bite in most cases did not exceed one day; there were differences by sex, incubation period. Clinical symptoms were similar, except for the erythematous form of LD (the presence of erythema migrans at the byte site of tick), because the vast majority of patients had a general infectious syndrome; general laboratory indicators varied. Confirmation of the diagnosis was based on the results of the complex application of molecular biological and serological research methods. Conclusions. The modern etiological structure of infections transmitted by ixodic ticks in the Sverdlovsk region is represented not only by TBE and LD, but also by new disease to our country, such as BMD, HGA, HME, while a high proportion of mixed infections in various combinations has been revealed.