Статья посвящена эпилепсии Кожевникова, одному из наиболее распространенных и по сути патогномоничных проявлений хронического течения клещевого энцефалита. Описаны стадийность в ее развитии, типы течения сформировавшейся кожевниковской эпилепсии, подходы к терапии. В статье представлен уникальный по продолжительности наблюдения случай хронического клещевого энцефалита (ХКЭ) (47 лет от начала заболевания и свыше 30 лет после вакцинотерапии). Показано, что замедленное развитие тяжелой неврологической симптоматики, прогрессирование болезни происходят на фоне дисиммуноглобулинемии. Штамм, выделенный от пациентки, обладал высокой нейровирулентностью для белых мышей, был высоконейроинвазивным, показал принадлежность к сибирскому подтипу вируса клещевого энцефалита. По мере прогрессирования ХКЭ развивался полиштаммовый иммунный ответ и напряженный иммунитет с высокой авидностью антител (через 30-32 года после вакцинотерапии). В неврологическом статусе – характерные постэнцефалитические изменения с элементами кортикальной моторной эпилепсии. Существенного когнитивного дефекта не было выявлено. The article is devoted to Kozhevnikov's epilepsy, one of the most common and, in fact, pathognomonic manifestations of the chronic course of tick-borne encephalitis. The stages in its development, the types of the course of the formed Kozhevnikovskaya epilepsy, and approaches to therapy are described. This material presents a unique case of chronic tick-borne encephalitis (TBE) (47 years from the beginning of the disease and more than 30 years after vaccination). It is shown that the delayed development of severe neurological symptoms and disease progression occur against the background of dysimmunoglobulinemia. The strain isolated from the patient had high neurovirulence for white mice, was highly neuroinvasive, and belong to the Siberian subtype of tick-borne encephalitis virus (TBEV). As TBE progressed, a polystrain immune response and a stressed immune response with high antibody avidity developed (30-32 years after vaccination). In the neurological status – pecular postencephalitic changes with elements of cortical motor epilepsy. No significant cognitive defect was detected.

Currently available vaccines against tick-borne encephalitis (TBE) are highly effective; however, they do not ensure 100% protection. Laboratory diagnostics of TBE in vaccinated patients remains poorly developed. Objective. To compare the dynamics of humoral immunity in unvaccinated and vaccinated patients and to develop an algorithm of specific laboratory diagnostics of TBE. Patients and methods. We have tested 276 unvaccinated and 59 vaccinated patients using enzyme-linked immunosorbent assay for the detection of IgG and IgM against antigens of tick-borne encephalitis virus (TBEV). In hemagglutination inhibition assay, we used dry TBEV reagent. TBEV RNA was detected using reverse transcription polymerase chain reaction (RT-PCR). Results. We have identified three types of humoral immunity dynamics in vaccinated and unvaccinated patients: seroconversion, stable antibody titers, and negative (reverse) antibody dynamics with an at least 4-fold decrease in antibody levels. Among 39 vaccinated individuals, 18 patients demonstrated seroconversion, while 16 patients had stable antibody titers and 4 patients had negative dynamics. Patients with chronic TBE demonstrated different variants of humoral immunity dynamics. Discussion. We discuss the variants of antibody dynamics described above and diagnostic methods on the example of vaccinated patients. In individuals with stable antibody titers, we used an original method for detecting the dynamics of antibodies against Siberian strain of TBEV. Conclusion. In case of seroconversion, the level of specific immunity in vaccinated patients was higher than that in unvaccinated patients and healthy individuals vaccinated against TBE. Negative antibody dynamics is the rarest variant of humoral immunity development. The diagnosis of TBE in patients with stable antibody titers is confirmed by the detection of TBEV antigen, increasing serum levels of IgM, detection of TBEV RNA in the cerebrospinal fluid, and isolation of the virus. Keywords: vaccinated patients, humoral immunity, diagnosis, tick-borne encephalitis

Relevance.Modern inactivated culture vaccines against tick-borne encephalitis (TBE) with at least 70% of the population living in the natural foci of the FE give a high epidemiological effect. Unresolved issues are the simplification of the cumbersome vaccination scheme, the optimal number of revaccinations, the protective titer of antibodies against the Siberian subtype of the TBE virus dominant in Russia.Goalof this work is to study the state of postvaccinal immunity in the population of the highly endemic area of the Trans-Urals.Materials and methods. 1381 blood serum of the population vaccinated from 3 to 13 times with vaccines was studied: unconcentrated culture inactivated from strain No. 205 of the TBE virus produced by «Virion», Tomsk, «EnceVir» produced by «Microgen», Tomsk, produced by Chumakov Federal Scientific Center for Research and Development of Immuneand-Biological Products of Russian.To identify specific antibodies – IgG, IgM, antigen of TBE virus, sets of reagents of ELISA from «Vector-Best» were used. Neutralizing activity of sera was determined by the index of neutralization index with 4 strains of the Siberian subtype of TBE virus.Results.The immune layer among the vaccinated population in 10 districts of the Kurgan region, which differ in epidemiological tension, ranges from 69.9% to 94.6%. The intensity of humoral immunity varied according to IgG titers in ELISA from 1: 100 – 1: 200 to 1: 3200 (rarely 1: 6400). The duration and intensity of immunity depends on the number of vaccinations and the number of missed remote revaccinations. Preservation and intensity of immunity with reliability P = 95%, higher in persons vaccinated 6–10 times compared with the group of vaccinated 3 times. In persons who had 4–8 booster dose of vaccine, the immunity persisted for 15–19–36 years with an IgG titer of not more than 1: 100. The neutralizing activity of the sera of vaccinated individuals with antibody titers from 1:100 to 1: 6400 was studied for the Siberian subtype of BCE. The degree of protection of the vaccinated population against the doses of the virus found in individual mites is determined. From the doses of the virus, 57% of the vaccinated population are most often found in mites, and from the dose of 105– 8%. Recommendations are proposed on the tactics of revaccination of the population, depending on the level of immunity.

Relevance.Тhe Ural Federal district (Ural Federal district) is a highly endemic tick-borne viral encephalitis (TBEV) territories in the Russian Federation. The epidemiological situation on the TBEV is studied in Sverdlovsk and Chelyabinsk regions and slightly shown in the Kurgan region. There is no information about the evolution TBEV, the structure of immunity population, vaccine prevention in the Kurgan region. The article presents the dynamics epidemiological situation on TBEV in the Kurgan region over a 30-year period.Materials and methods: Used expedition reports, viral encephalitis named after the Academy of medical Sciences of the USSR for 1983–2007, as well as materials of medical institutions of the Kurgan region 2007–2017. For population immunity used: hemagglutination test (HAI-test), neutralization test (NT). To identify specific antibodies – IgG, IgM, antigen of TBEV, sets of reagents of ELISA from «Vector-Best» were used. To immunotypicalli and genotypically Strains and isolates RNA of TBEV isolated in 1983–2007, used precipitation in agar (RDPA) and by RT-PCR technique in real time with genotypespecific probes.Results and discussions: Kurgan region is a highly TBEV endemic area. the morbidity rate – 18,3 per 100 thousand people 1983. Maximum elevation – 44.1 in 1996 to and decrease to 13.5 in 2000–2012. The immune part of the population according hemagglutination tests, on epidemiologically significant territories is 15–20%, (66% NT), in the regions with sporadic incidence is 8%, (21–50% NT), in non-endemic territories – 3%. At the present stage, the region marked the expansion of nosoareal TBEV due to the previously less significant Eastern regions. In Kurgan region vaccination coverage against TBE 39.3%. The clinical efficacy of vaccination was manifested in an increase in fever forms of TBE disease and a decrease in meningeal and focal forms of the disease. In the period 2004–2012 the number of vaccinated patients was 20.3% of the total number of patients.Сonclusions. Evolution of tick-borne encephalitis manifested the expansion of nosoareal TBEV, increase seasonal activity of ticks, the TBEV Siberian subtype is absolutely dominating.

Relevance. Modern inactivated culture vaccines against tick-borne encephalitis (TBE) with at least 70% of the population living in the  natural foci of the FE give a high epidemiological effect. Unresolved  issues are the simplification of the cumbersome vaccination scheme,  the optimal number of revaccinations, the protective titer of  antibodies against the Siberian subtype of the TBE virus dominant in Russia. Goal of this work is to study the state of postvaccinal immunity in the population of the highly endemic area of the Trans-Urals. Materials and methods . 1381 blood serum of the population vaccinated from 3 to 13 times with vaccines was studied: unconcentrated culture inactivated from strain No. 205 of the TBE  virus produced by «Virion», Tomsk, «EnceVir» produced by  «Microgen», Tomsk, produced by Chumakov Federal Scientific Center for Research and Development of Immuneand-Biological Products of  Russian.To identify specific antibodies – IgG, IgM, antigen of TBE  virus, sets of reagents of ELISA from «Vector-Best» were used.  Neutralizing activity of sera was determined by the index of  neutralization index with 4 strains of the Siberian subtype of TBE  virus. Results. The immune layer among the vaccinated population in 10 districts of the Kurgan region, which differ in epidemiological tension, ranges from 69.9% to 94.6%. The intensity of humoral immunity  varied according to IgG titers in ELISA from 1: 100 – 1: 200 to 1:  3200 (rarely 1: 6400). The duration and intensity of immunity  depends on the number of vaccinations and the number of missed  remote revaccinations. Preservation and intensity of immunity with  reliability P = 95%, higher in persons vaccinated 6–10 times  compared with the group of vaccinated 3 times. In persons who had 4–8 booster dose of vaccine, the immunity persisted for 15–19–36 years with an IgG titer of not more than 1: 100. The neutralizing  activity of the sera of vaccinated individuals with antibody titers from 1:100 to 1: 6400 was studied for the Siberian subtype of BCE. The  degree of protection of the vaccinated population against the doses  of the virus found in individual mites is determined. From the doses  of the virus, 57% of the vaccinated population are most often found  in mites, and from the dose of 105– 8%. Recommendations are  proposed on the tactics of revaccination of the population, depending on the level of immunity.

Chronic tick-borne encephalitis (CTBE) is a severe form of the disease, leading to permanent disability and death. Most cases of CTBE caused Siberian subtype of a virus of tick-borne encephalitis virus (TBEV), dominant in the Russian Federation. The pathogenesis of CTBE associated with persistence of TBEV in the central nervous system and the organs of the immune system. Specific vaccine therapy with using of inactivated full-virion vaccines prevents immunosuppression, leading to activation of persisting tick-borne encephalitis. The article describes various schemes of CTBE vaccinotherapy. Dynamics of humoral immunity in CTBE caused by Siberian subtype of TBEV. In the early stages and during remission antibodies against this subtype are detected. Vaccine therapy increases the level of immunity to all subtypes of TBEV, slowing the progression of the disease. In seronegative status of the patient vaccine therapy is not effective: from the central nervous system of a deceased patient severe strain «Zausaev» was isolated. Mechanisms of high immunity after 30-32 years after vaccine therapy and advantages of vaccine therapy compared with treatment of CTBE using specific immunoglobulin are discussed.

In the Yaroslavl region (Central Federal District of Russia), endemic of tick-borne encephalitis (TBE), the features of epidemiology of this infection were studied during 1992-2012. Cyclical fluctuations in the incidence of TBE, the lack of the trend to decrease of the incidence were observed, the average annual incidence was 1,6 ± 0,32 per 100 thousand ofpopulation. The prevalence offebrile forms of disease was 62,2%, meningeal forms - 16,3%, the total percentage offocal forms was 13,9%. Manifestations of evolution of TBE were: the increase of the epidemiological significance of anthropogenically transformed natural foci, anthropurgical foci of TBE, until 81% of TBE cases were unvaccinated citizens, the high lethality of 4% and the high frequency of cases of alimentary infection of TBE of 7,8% with lethality of 10,8%. The aethiological agent of 10 lethal cases was Siberian subtype of TBE virus.

1 . VAccINE thERApy OF chRONIc tIcK-BORNE ENcEphALItIS 1 Chumakov Institute of polyomielitis and viral encephalitides of Russian academy of medical sciences, 142782, Moscow, Russia; 2 Aldan central hospital, 678900 Republic Saha (Yakutia), Aldan, Russia. Chronic tick-borne encephalitis (CTBE) is a severe form of the disease, leading to permanent disability and death. Most cases of CTBE caused Siberian subtype of a virus of tick-borne encephalitis virus (TBEV), dominant in the Russian Federation. The pathogenesis of CTBE associated with persistence of TBEV in the central nervous system and the organs of the immune system. Specific vaccine therapy with using of inactivated full-virion vaccines prevents immunosuppression, leading to activation of persisting tick-borne encephalitis. The article describes various schemes of CTBE vaccinotherapy. Dynamics of humoral im- munity in CTBE caused by Siberian subtype of TBEV. In the early stages and during remission antibodies against this subtype are detected. Vaccine therapy increases the level of immunity to all subtypes of TBEV, slowing the progression of the disease. In seronegative status of the patient vaccine therapy is not effective: from the central nervous system of a deceased patient severe strain «Zausaev» was isolated. Mechanisms of high immunity after 30-32 years after vaccinу therapy and advantages of vac- cine therapy compared with treatment of CTBE using specific immunoglobulin are discussed. Key w ords: tick-borne encephalitis; chronic tick-borne encephalitis; Siberian subtype of tick-borne encephalitis virus; persistence; vaccine therapy; immune system; antibodies.

In the Kurgan region, the Siberian subtype of the tick-borne encephalitis virus (TBEV) is dominant. The vaccines prepared from Far-Eastern TBEV subtype are used in this area. Among TBE patients in 2007-2011, 23.79% were vaccinated according to complete or incomplete course. 76.9% of persons were vaccinated with Encevir vaccine, Tomsk. An unusual focal form of TBE with fulminant disease with lethal outcome was developed in a patient who was vaccinated 6 times with heterotype vaccines produced using the strains of the Far-Eastern TBE subtype. inoculation of immunoglobulin in hospital produced aggravation of clinical symptoms, development of convulsions, brain oedema, and respiratory distress syndrome. The disease continues only 55 hours from first symptoms to fatal outcome. Siberian subtype of TBEV was isolated from patient spinal cord (Kurgan-118-2010 strain). Possible mechanisms of this disease are discussed.

Eighteen polytypic tick-borne encephalitis virus (TBEV) strains containing the fragments of E and NS1 protein genes of Siberian and Far Eastern, occasionally Siberian and European subtypes were isolated in the European and Asian parts of the tick-borne encephalitis (TBE) area. They were identified using real-time polymerase chain reaction, hybridization-fluorescence detection with genotype-specific probes, restriction fragment length polymorphism analysis, and E protein sequencing. The polytypic strains were isolated from individual Ixodes persulcatus ticks, their pools, from the blood of patients and the brain of dead patients. The isolation rates of the polytypic strains in the sympathry area of different TBEV subtypes ranged from 4.4% (the Irkutsk Region) to 15.1% (the Yaroslavl Region). In addition to 2 polytypic strains, a strain similar to the TBEV 886-84 strain was isolated. The TBEV subtypes entering into the composition of the polytypic strains show nongenetic interactions, such as neutral replication or competition. The polytypic strains are stable during passages in the cultured pig embryo kidney epithelial cells and on cloning. Mouse brain passage promotes dissociation of polytypic strains. The conditions for the formation of polytypic strains and their role in the etiology of TBE are discussed.

Eighteen polytypic tick-borne encephalitis virus (TBEV) strains containing the fragments of E and NS1 protein genes of Siberian and Far Eastern, occasionally Siberian and European subtypes were isolated in the European and Asian parts of the tick-borne encephalitis (TBE) area. They were identified using real-time polymerase chain reaction, hybridization-fluorescence detection with genotype-specific probes, restriction fragment length polymorphism analysis, and E protein sequencing. The polytypic strains were isolated from individual Ixodes persulcatus ticks, their pools, from the blood of patients and the brain of dead patients. The isolation rates of the polytypic strains in the sympathry area of different TBEV subtypes ranged from 4.4% (the Irkutsk Region) to 15.1% (the Yaroslavl Region). In addition to 2 polytypic strains, a strain similar to the TBEV 886-84 strain was isolated. The TBEV subtypes entering into the composition of the polytypic strains show nongenetic interactions, such as neutral replication or competition. The polytypic strains are stable during passages in the cultured pig embryo kidney epithelial cells and on cloning. Mouse brain passage promotes dissociation of polytypic strains. The conditions for the formation of polytypic strains and their role in the etiology of TBE are discussed.

Background: Tick-borne encephalitis virus (TBEV) is transmitted to humans by Ixodid ticks causing >10,000 cases of disease annually. The risk of human infection relates to the efficiency of virus transmission between infected and uninfected ticks. Here we identify specific mutations in the viral envelope protein that affect transmission efficiency of TBEV between ticks. Methods: The genomes of 4 field isolates of TBEV deficient in haemagglutination, were sequenced and recreated by site-directed mutagenesis, in a TBEV infectious clone. They were then compared with the wild-type infectious clone in mice, porcine kidney PS cells and adult and nymphal I. ricinus ticks. Results: Sequence analysis revealed unique amino acid substitutions D67G, E122G or D277A in the envelope glycoprotein. Each mutation resulted in an increase of net charge and hydrophobicity on the virion surface. When introduced individually into the TBEV infectious clone (IC), each substitution inhibited haemagglutination and reduced mouse neuroinvasiveness from 65% to 15-30%. Antibody production in infected mice was 1.5-3 times lower for IC-E122G and IC-D277A suggesting lower levels of viraemia and/or deficient immune stimulation induced by these viruses. All mutants demonstrated delayed growth in PS cells during the first 24hpi; however, mutant IC-D67G exhibited significantly better growth characteristics than IC-E122G and IC-D277A. The reproduction of IC-E122G and IC-D277A in fasting ticks was similar to that of control HA positive virus whereas the titres of IC-D67G were significantly lower (2.5-3 vs. 1-2 log10PFU/ml, respectively). In feeding ticks, the titre of IC-E122G increased approximately 1000-fold and IC-D277A and IC-D67G - approximately 300-fold, whereas for control virus the increase was about 10-fold. Non-viraemic transmission efficiency from infected to uninfected ticks was increased by each individual substitution in nymphal I. ricinus (Figure 1). Figure 1 Tick-to-tick transmission rate (clear bars) is expressed as the proportion of infected I.ricinus nymphs. Black triangles show the average virus titres in individually infected recipient nymphs as determined by plaque assay. Conclusion: We hypothesize that the mechanism of adaptation of TBEV to its host utilizes the shift of charge/hydrophobicity at several critical aminoacid residues exposed on the virion surface. This shift results in different biological consequences depending on the localisation of certain aminoacid residue. The results provide valuable information concerning the maintenance in nature and the emergence of pathogenic variants of TBEV. Abstracts for SupplementInternational Journal of Infectious DiseasesVol. 14Preview Full-Text PDF Open Archive

The evolution of tick-borne encephalitis (TBE) is marked by the expanded nosological area, the transformation of landscapes, the formation of anthropurgic foci, the change of environmental systems, the increase of mortality rate mainly among urban dwellers, as well as pathomorphism. The evolution of natural TBE virus (TBEV) populations was studied in Eastern and Western Siberia, Middle Urals, and the European part of the nosological area. The paper first describes the types of evolutionary transformations of viral populations under the conditions of a varying environmental and epidemiological situation. These include: 1) the change of TBEV subtypes over 50-60 years; substitution of the Far-Eastern subtype for its Siberian subtype (the Sverdlovsk and Kemerovo regions); 2) the steady-state circulation of one Siberian subtype with mutanttypes being accumulated (the Vologda region); 3) co-existence of the Far-Eastern and Siberian subtypes with the common vector Ixodes persulcatus (the Yaroslavl and Irkutsk regions, etc.); 4) original mixed TBEV strains including the gene sites of proteins E and NSI of two subtypes. There is new evidence that the Siberian subtype is able to induce focal TBE forms, leading to death.

The study has covered 11 strains and 8 RNA iso : lates of tick-borne encephalitis, corresponding to the Siberian and the Far Eastern genotypes within the E-gene complete sequence. The isolation period for strains refers to 40 years for the Siberian genotype and 70 years for the Far Eastern genotype. The study confirmed the earlier findings that strains and isolates of Siberian genotype could be subdivided into distinct branchs (Asian and European branchs), where the Asian splits into two smaller branches, one of which corresponds to the prototypic strain Zausaev, and the other one to the strain Vasilchenko. The European and Asian subtypes carry stable amino acid markers on E gene (positions 175 and 234). The Far Eastern isolates involve a distinct group of isolates from Hokkaido, namely the Oshima. Strains from Ural, Western Siberia and Far East, don’t have stable amino acid markers on E gene. The entire genome nucleotide sequence was obtained for two strains, one of which (178-79) was isolated in 1979 in the Irkutsk region from I.persulcatus ticks, and the other (886-84) was also isolated in the Irkutsk region from Cl. rufocanus in 1984. The nucleotide and amino acid sequences analysis have referred both strains to the Far Eastern genotypes.

Chita region is the least studied among other East-Siberian regions in respect of tick-borne encephalitis (TBE); population of TBE virus, colonizing the focal territories, is not studied well enough. High rate of local forms of the TBE and high mortality level of this disease in Chita region at the background of lower morbidity level as compared with contiguous territories was noted. First the representative group of TBE virus strains, isolated from dead people (from 1995 up to 2003), have been investigated with the help of molecular-biological methods for studying of etiological structure of local TBE forms with lethal outcome. Some phenotypic characteristics of the isolated strains were studied. It was shown that TBE cases in Chita region depended on two independent subtypes of the TBE virus — Far-Eastern and Siberian, — and both were etiologically connected with local TBE forms with lethal outcome. Strains of the TBE virus, containing genome areas of the Far-Eastern and the Siberian subtypes take part in progress of local forms too. Retrospective analysis of strains allows to argue about stability and duration (more than 40 years of observation) of the Siberian TBE virus subtype circulation in natural foci of the region.