Modification of isothermal test for detecting DNA of pathogens of tick-borne borreliosis.

Early diagnosis of tick-borne borreliosis determines the indications for etiotropic therapy, and the detection of borrelia in a tick that has bitten you serves as the basis for antibiotic prophylaxis. To determine the causative agent of borreliosis, PCR methods are most widely used, which requires special conditions for organizing the work of laboratories and the use of expensive equipment. In addition, the procedure for isolating bacterial DNA and subsequent amplification takes several hours of working time. At the same time, methods for detecting borrelia in the isothermal LAMP-reaction are described, which makes it possible to significantly speed up the diagnosis, does not require complex equipment and highly qualified personnel. It is also known that LAMP in some cases allows analysis without prior extraction of nucleic acids. The purpose was a development of a modified test for isothermal detection of DNA of borreliosis pathogens for an accelerated result and the possibility of excluding the stage of nucleic acid extraction. We used 40 samples of Borrelia DNA and 11 Ixodes persulcatus ticks. To shorten the detection time for Borrelia, the previously described LAMP method was modified by the introduction of additional loop primers. The copy number of the positive DNA sample of the borrelia plasmid was estimated using digital PCR. The results of the LAMP reaction were compared with those of the commercial PRC-RT test. The additional use of loop primers approximately halved the detection time for Borrelia DNA without affecting the comparative diagnostic efficiency. The analytical sensitivity limit of the modified LAMP method was 4 copies/µl or 21 molecules of the plasmid standard added to the reaction. In comparative testing with RT-PCR, the sensitivity of the LAMP method is 90%, and the specificity is 100%. The possibility of detecting borrelia in ticks without the stage of DNA extraction has been demonstrated for the first time. A modified isothermal method for the detection of pathogens of tick-borne borreliosis has been developed, which allows analysis within 20-30 minutes, including in ticks without preliminary DNA extraction.

[Clinical and laboratory diagnosis of tick-borne rickettsioses in areas of low risk of infection Rickettsia sibirica.]

For the first time, a comparative description of clinical and laboratory parameters in patients with clinical signs of tick-borne rickettsiosis in a natural focus with a low risk of infection with R. sibirica and circulation of R. raoultii is given, depending on the results of serological verification of the diagnosis. Established almost complete coincidence of clinical and laboratory parameters in patients with tick-borne rickettsiosis, regardless of the presence of antibodies to R. sibirica and / or R. raoultii. It was shown that even the complex use of complement fixation test, indirect immunofluorescent test and ELISA for the detection of antibodies to R. sibirica does not allow verification of the diagnosis in a third part of patients with pathognomonic signs of tickborne rickettsiosis. In seropostive patients, antibodies to R. sibirica prevailed, which makes it impossible to differentiate cases of tick-borne rickettsiosis of different species etiology. The possible reasons of the phenomenon of «seronegativeness¼ of patients with tick-borne rickettsiosis and approaches to its study are discussed. It is concluded that with the existing diversity and insufficient knowledge of rickettsiae circulating in natural foci, and the current state of laboratory diagnostics, the basis for the diagnosis of «Tick-borne rickettsiosis¼ should be the clinical and epidemiological signs of this infectious disease, which must be recorded in the established order even no serological verification. For such cases, ICD-10 has two encoding options: A 79.9 - Rickettsiosis, unspecified (infection caused by rickettsia, no other indication) and A 77.9 - Spotted fever, unspecified (tick-borne fever, no other indication) [mkb-10.com].

[The molecular biological methods of express-detection of pathogens in ticks taken way from patients as a basis of preventive therapy of tick transmissible infections.]

The complex molecular biologic study of ticks, took off from people in the Omskii oblast during Spring-Summer periods in 2014-2016 established their infection with agents of tick's transmissive infections and testifies a significant risk of infection of population. The analysis of ticks I. persulcatus established that rate of detection of DNA of borrelia made up to 59,5%, rickettsia - 30.6%, anaplasmae and erlichiae - 5.9%. The analysis of ticks D. reticulatus by polymerase chain reaction detected DNA of rickettsia in 20.5%, borrelia - in 6.6%, RNA of tick-borne encephalitis virus - in 3.6%. No DNA of anaplasmae and erlichiae was detected. During sequencing of tests positive to rickettsia the most often Rickettsia raoultii was identified. The approaches to expressdiagnostic and preventive therapy of tick-born transmissive infections were substantiated with consideration for mixt-infection of agents and pathogenic characteristics of developing nosologies. The algorithms of laboratory analysis regulated by the Sanitary Regulations 3.1.33-10-15 "Prevention of infections transmitted by ticks" require a broader implementation.

[THE LABORATORY DIAGNOSTIC OF HUMAN TRANSMISSIBLE INFECTIONS IN COMBINED HOT SPOTS].

The occurrence of common disease carriers of various pathogens condition wide prevalence of combined hot spots of tick infections. The comprehensive approach to laboratory diagnostic of these infections is substantiated taking into account specter of main pathogens transmitted by ticks.

[ON THE ROLE OF RICKETTSIA RAOULTII IN THE EPIDEMIOLOGY OF RICKETTSIOSES IN RUSSIA].

The paper analyzes data on the prevalence and possible epidemiological importance of Rickettsia raoultii. The possible risk of infection in the population was assessed from the results of a serological study of patients after tick suction and from those of molecular biological determination of contamination of removed carriers. The place of Rickettsia raoultii among other rickettsia causing rickettsioses of a tick-borne spotted fever group is assessed in Russia.

[A study of possible transovarial and transphase transmission of borreliae by the tick Dermacentor reticulatus (Ixodidae)].

A study of possible transovarial and transphase transmission of borreliae by the tick Dermacentor reticulatus is carried out. The possibility of borreliae transmission by the ticks of this species being infected spontaneously as well as experimentally is shown in principle. Although borreliae are preserved in the organism of D. reticulatus, low values of the infestation are established in the different stages of D. reticulatus development and in all steps of the study. D. reticulatus may be involved in the process of borreliae circulation in natural foci of tick-born borreliosis, but this species has no a significant importance for the maintenance of it.

[The preliminary results of an ecological epidemiological study of Lyme disease in western Siberia]. / Predvaritel'nye rezul'taty ékologo-épidemiologicheskogo izucheniia bolezni Laima v Zapadnoi Sibiri.

Studies of Ixodes persulcatus ticks in Omsk, Kurgan, and Novosibirsk regions revealed natural foci of Lyme's disease. Vector infection rate varied from 21 to 23.5% in the Omsk region, from 30 to 52.9% in the Kurgan region, and from 15 to 58.3% in the Novosibirsk region. Serologic screening of inpatients hospitalized during the epidemic season of 1991 with suspected tick-borne encephalitis and Lyme's disease confirmed the latter condition in 10.8% of the examinees in the Omsk and in 10% in the Kurgan regions. These data indicate the presence of active natural foci of Lyme's disease on the examined territories in west Siberia.

[The evaluation of the efficacy of obzidan and sydnopharm in patients with stenocardia of effort]. / Otsenka éffektivnosti obzidana i sidnofarma u bol'nykh so stenokardiei napriazheniia.

It is concluded that obsidane and sidnopharm were effective in the treatment of patients with exertion stenocardia in outpatients conditions. The patients continued to work. Obsidane treatment was most effective in patients with the hyperkinetic type of circulation, increased blood viscosity and hypercoagulation syndrome.