In this work there is shown the value of the immunological screening in the organization and implementation of the epidemiological surveillance of natural focal infections. The application of this method with regard to this group of infections, allows to detect the frequency and the level of so-called "pro-epidemising" of the population, also helps with the identification of the mild, subclinical, latent forms of disease not detected by the clinical method of the diagnosis. The obtained results clearly demonstrate extensive nosoareals of natural focal infections in the territory of the subject among the population with different levels of seropositivity, and thus indicate to the needfor the implementation of the immunological screening in the future as an relevant diagnostic tool in the formulation of the diagnosis in epidemiological surveillance system.

As a result of social and economic transformation taking place in the Russian Federation over the last 20 years the number of urban inhabitants has been steadily elevating. Urban areas are increasing. Cities absorb not only the surrounding communities, but also the non-urban fauna and flora, and with them the natural foci of certain feral herd infectious (FHI) diseases. The study found that the results confirm the existence of the necessary conditions for the formation and operation of natural foci in the metropolis - Ulyanovsk. 3 out of the 4 infections mentioned above: leptospiroses (39.2%), followed by Hemorrhagic fever with renal syndrome (HFRS) (17,9%) and Ixodes tick-borne borreliosis (ITB) (14,7%) obtained a wide dissemination. In such separate territories of the region center as Park Pobedy, Belyy Klyuch», Park Karamzina, park «Yunost'» the existence of conjugate foci of the FHI (HFRS, Tick-borne viral encephalitis (TVE), leptospirosis) has been proved.

Coxiellosis (Q-fever) is a systemic natural focal zooanthroponosis disease, which has a very wide geographical area. A variety of clinical manifestations and the absence of pathognomonic signs of illness forces to use for making a definite diagnosis complex of techniques including epizootological, epidemiological data, clinical manifestations, and certainly the results of several serological tests designed to detect antibodies to Coxiella burnetii. There is presented a description of an acute case of Q - fever in a child in the subject, characterized as trouble-free of Coxiellosis from 70-ies of the last century.

The causative agent of Q fever, the intracellular pathogen Coxiella burnetii, is found almost worldwide; many types of blood-sucking ticks that are dangerous to animals and humans are involved in the circulation of the pathogen. Using molecular-genetic methods, closely related species of microorganisms of the genus Coxiella sp. have been discovered, some of which are endo-symbionts of ticks, and some can survive in the human body, causing an infectious process. The existence of species whose genes are similar in nucleotide sequence to those of C. burnetii makes it difficult to diagnose the pathogen in arthropod vectors. The aim of this work was to consider the use of PCR and sequencing of an extended 16S rRNA gene fragment for molecular diagnostics and differentiation of C. burnetii from Coxiella-like microorganisms. Materials and methods. Individual samples of blood-sucking ticks were examined to detect bacteria of the genus Coxiella sp. applying standard PCR. For positive samples, an extended fragment of the 16S rRNA gene was obtained and examined by sequencing and multiple alignment with homologous sequences. Results and discussion. Of the 96 examined ticks collected in the Ulyanovsk Region, one was positive for the presence of C. burnetii DNA and one – for the presence of Coxiella sp. The greatest similarity for the C. burnetii isolate was noted in comparison with Western European strains, for the Coxiella-like microorganism - with closely related bacteria from ticks of the same species. Unique polymorphisms for the detected microorganisms were identified. It has been established that genus-specific primers to the 16S rRNA gene fragment are able to amplify not only bacteria of the genus Coxiella sp., but also genetically distant species. Analysis of the sequence of the extended 16S rRNA gene fragment makes it possible to differentiate C. burnetii from Coxiella-like microorganisms; some gene polymorphisms appear to have arisen through microevolution in different geographic regions. In the European part of the Russian Federation, Coxiella-like bacteria have been uncovered for the first time.

Diagnosis of Ixodes tick borreliosis (SDS) at an early stage of the disease is not perfect that creates problems in a timely diagnosis. This paper presents the results of a comparative analysis of the incidence rate of Ixodes tick borreliosis (CBI) in the Ulyanovsk region for the period 2002-2013; there is considered the pattern of mite species and the results of their research on Borrelia species (2011-2013).