Vol 10, No 1 (2020)

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Full Issue


Advanced technologies in diagnostics of viral diseases of unknown etiology

Khafizov K.F., Speranskaya A.S., Matsvay A.D., Shipulin G.A., Dedkov V.G.


Unveiling origin of infectious diseases with unknown etiology is one of the major issues in contemporary medicine, since a laboratory-confirmed diagnosis may, unfortunately, be obtained solely in very few cases. Because the majority of the most common mid-latitude infections display a typical overt clinical picture, this problem has not been paid a proper attention until recently. Recent rise in incidence rate of infectious diseases lacking typical clinical signs observed lately makes it extremely important to consider the problem more closely. It is believed that such trend is due to a whole body of reasons, including impaired sanitary control, increased both internal and external migration flows, refusal of vaccination in case of long-lasting epidemic wellbeing, emergence of atypical bacterial strains of bacteria resulting from irrational antibiotic therapy etc. Viruses constitute the largest group of organisms on our planet accounting for them as the most common causative agent of infectious diseases of unknown etiology. Some estimates obtained by mathematical modeling propose that at least 320,000 types of viruses capable of infecting mammals may exist, most of which have not been described yet. Hence, monitoring circulation of the known viral pathogens, tracing down their spreading and changes in genome nucleotide sequence as well as revealing new types of viruses become important aspects of epidemiological surveillance necessary for timely response to emerging threats, prediction and early detection of outbreaks both in humans and animals. This review summarizes traditional molecular genetics methods for detection of viral pathogens, such as PCR, real-time PCR, Sanger sequencing with pre-cloning, and methods based on the second and third generation sequencing. Therefore, a more detailed overview was provided to diverse methods based on using such technologies because viral infectious agents investigated with high-throughput sequencing (or NGS — Next Generation Sequencing) has been increasingly appreciated as feasible for diagnostics, disease control, molecular epidemiology and infection control. Finally, a special attention was also paid to the approaches used to enrich the viral genetic material in samples containing low amount of pathogen nucleic acids.

Russian Journal of Infection and Immunity. 2020;10(1):9-25
pages 9-25 views

Genetic determinants of virulence and drug resistance of Mycobacterium avium subsp. hominissuis — a causative agent of mycobacteriosis in humans

Starkova D.A., Narvskaya O.V.


Among the members of the large group of non-tuberculous mycobacteria (comprising more than 180 species), M. avium subsp. hominissuis (MAH) is the most significant causative agent of pulmonary infection in immunocompetent individuals as well as disseminated infection in immunocompromised hosts, e.g. human immunodeficiency virus (HIV)-positive patients. Due to increased incidence rate of mycobacteriosis, especially in HIV infection, much still need to be learnt about the MAH genetic control and virulence mechanisms. Deciphering the genome contents of the M. avium strain 104 (isolated from an AIDS patient with disseminated MAH disease) allowed to compare genome sequences of M. avium strains to gain insights into genomic diversity associated with variable hosts and environments. Comparative genome analysis of MAH strains isolated from patients with pulmonary and disseminated forms of mycobacteri-osis revealed differences in the structure of the genome, affecting the key virulence genes. This review provides current data on the genetic determinants of MAH virulence associated with the initial phase of infection. Several mycobacterial virulence-associated gene families, such as mce (mammalian cell entry), mmp (mycobacterial membrane proteins), pe/ppe and esx expressed by MAH during human infection are thought to be crucial for adhesion, entry, survival, and reproduction inside host macrophages. The genetic mechanisms of MAH survival in human macrophage cell culture as well as mice exposed to toxic effects of reactive oxygen, nitric oxide, bactericidal proteins (cathelicidin) are discussed. The MAH survival in the latency-like state is important for pathogen dissemination. Some genetic and phenotypic features of MAH (absence of a cord factor, presence of plasmids, potential to “switch” morphological types of colonies) are compared with M. tuberculosis. In addition, we summarized current state of MAH drug discovery, a role of MAH intrinsic multidrug resistance, genetic control, as well as mechanisms underlying formation of resistance to various groups of antibiotics in MAH strains.

Russian Journal of Infection and Immunity. 2020;10(1):26-34
pages 26-34 views

Innate immune receptors in development of Mycobacterium tuberculosis infection

Lapshtaeva A.V., Zhivechkova E.A., Sychev I.V., Evsegneeva I.V., Novikov V.V.


According to the World Health Organization, over 10 million new tuberculosis cases are reported annually worldwide. According to the 2017 Federal State Statistics Service Report, incidence rate for active TB infection in the Russian Federation was 109.8 cases per 100,000 population, of which 41.3% accounted for chronic disease form. Regardless of climatic conditions, high prevalence of TB infection, is not only due to high Mycobacterium tuberculosis viability, but also its ability for long persistence in human body and reactivation after an unlimited period of dormancy. The outcome of infection is largely determined by host immunoreactivity and its ability to develop protective immune response. In addition, status of immune system also underlies tuberculosis course after the onset: either as a localized form, or as a form with extensive damage to the lungs and even other organs observed in generalized infection. In recent decades, a great attention was paid to examining mechanisms of adaptive cell immunity played in pathogenesis of TB infection. No doubt, adaptive immunity is a powerful defense system providing a targeted specific immune response, but now it is becoming clear that it represents solely an effector arm of innate immunity. Innate immunity is a phylogenetically more ancient, inherited system largely aimed at ensuring rapid pathogen elimination and preventing development of infection at early stages when adaptive immunity ongoing antigen-specific maturation. Mechanisms of innate immunity mediated by cells, diverse receptors, molecules and their complexes, found on various cells. Activation of innate immunity begins with recognition of conserved molecular groups present in various pathogens called pathogen-associated molecular patterns (PAMPs), which are sensed by pathogen recognition receptors (PRRs). Here, we review current data on the role of innate receptors in recognizing M. tuberculosis-derived PAMPs, production of immunoregulatory cytokines and activation of signaling pathways playing a crucial role in the regulation of necroptosis, apoptosis and autophagy of infected macrophages. Significance of innate mucosal factors in implementing immune response to M. tuberculosis is discussed. In particular, Toll-like receptors, scavenger-receptors, mannose receptor, DC-SIGN etc. were described to participate in development of M. tuberculosis immunity. The data on single nucleotide polymorphic variants for innate genes are shown, which predispose to developing tuberculosis and affecting its course.

Russian Journal of Infection and Immunity. 2020;10(1):35-48
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Pattern of lactoferrin anti-influenza virus inhibitory activity

Zorina V.N.


Active antigenic drift allows the influenza virus to partially or completely avoid recognition by the immune system. For treatment, inhibitors of the proton-selective ion channel M2 and inhibitors of neuraminidase are used, which have undesirable side effects and provoke the emergence of treatment-resistant strains of the virus. This justifies the need to search for new therapeutic agents. Lactoferrin (LF) is a glycoprotein with a molecular mass of 75—80 kDa, capable for binding metal ions. The highest concentrations of LF are detected in colostrum and milk, a significant amount is deposited in neutrophil granules. The structure of the LF domains of human milk, cow, goat, pig, horse, camel, buffalo is homologous. LF interacts with both specific receptors and endocytosis receptors (LRP), Toll-like, signal receptors on the surface of various cell types. Lactoferrin of humans and animals has a high antiviral activity. This glycoprotein modulates the immune system, including the humoral and cellular immune responses, and regulates redox reactions. However, literature data on the role of this protein in the prevention and treatment of influenza are few. LF inhibitory activity against influenza A and B viruses has been described, including H1N1, H5N1, H7N1, H3N2 strains. It has been established that LF binds virus hemagglutinin, preventing interaction with the cell, blocks programmed cell death through interaction with caspase 3 for preventing the spread of the virus at the later stages of the infection, and blocks virus assembly. Peptides synthesized on the basis of LF C-domain structure demonstrate high inhibitory activity against virus. The use of LF as an adjuvant for vaccines is more effective than of aluminum oxide. Further study of LF effects on influenza virus and on the immune response during infection is necessary to develop new methods of prevention and treatment.

Russian Journal of Infection and Immunity. 2020;10(1):49-54
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Impact of IgG Fc-fragments on experimental glomerulonephritis induced by Streptococcus pyogenes strain binding various immunoglobulin classes

Burova L.A., Pigarevsky P.V., Snegova V.A., Totolian A.A.


The pathogenesis of poststreptococcal glomerulonephritis (PSGN), a major complication of acute infections caused by group A streptococci (GAS) remains unclear. Several theories, based on the role of certain streptococcal virulence factors, as well as immunological mimicry between GAS and renal tissue, have been proposed. Earlier, we reported that many virulent clinical GAS isolates showing confirmed nephritogenic activity were capable of nonimmune Fc binding of monomeric or aggregated IgG. Moreover, a rabbit model of PSGN allowed to obtain findings regarding a crucial role of streptococcal IgG Fc binding proteins belonging to the M family surface proteins, in the onset of PSGN. Rabbits injected with inactivated IgGFcBP-positive streptococci, acquired changes in the renal tissue with deposited IgG and complement C3, as well as signs of immune inflammation characteristic for human PSGN. Also, it was shown that the induction of experimental glomerulonephritis could be inhibited after normal IgG or its purified Fc fragments were inoculated at early stages of the process. The data obtained in rabbits injected with group A streptococcal type M60 also showed pathogenic functions of the IgA Fc-binding proteins of GAS. The aim of the study was to examine inhibiting activity of the purified rabbit IgG Fc fragments on the manifestations of glomerulonephritis induced by S. pyogenes strains capable of binding diverse forms of immunoglobulins such native IgG, immune complexes, and IgA.

Materials and methods. GAS strains of emml, emml2 and emm60 genotypes were used to induce PSGN or IgA-nephropa-thy in rabbits. Fc fragments derived from rabbit IgG were obtained by enzymatic digestion and purified by affinity chromatography on a protein G-sepharose FF column. Immunomorphological changes of renal tissue were estimated by morphometric analysis.

Results. In the present study, using the rabbit model, we revealed pathological changes of different intensity and localization in the renal tissue. For streptococci of the emm1 and emm12 genotypes, PSGN was characterized by deposition of IgG or IgG-anti-IgG immune complexes within the basal glomerular membrane. Morphological changes were evaluated as a membranous-proliferative glomerulonephritis. Meanwhile, IgA-glomerulonephritis is characterized by deposition of IgA in mesangial cells of glomeruli, leading to the mesangial-proliferative glomerulonephritis or IgA-nephropathy. Intravenously administered purified Fc fragments derived from normal rabbit IgG varied in effects on pathological processes: (i) IgG Fc fragments of fully inhibited development of the PSGN induced by IgG Fc binding strain of emml genotype, (ii) IgG Fc fragments of partially reverted changes caused by the emm12 genotype strain, which was binding only to immune complexes, and (iii) had no effects on pathological changes caused by the emm60 genotype GAS strain, which was binding only IgA.

Conclusion. The data obtained point and emergence of differences in mechanisms of renal lesions development at glomerulonephritis, depending on the emm genotype of GAS strain. In addition, it also confirmed GAS-derived involvement for various IgFc-receptor proteins in the pathology. Further studies on potential prophylactic or curative effects of IgG Fc fragments in PSGN should therefore be of interest. The findings might suggest a new therapeutic approach for non-suppurative poststreptococcal diseases.

Russian Journal of Infection and Immunity. 2020;10(1):55-63
pages 55-63 views

In vitro interaction of hormone-conditioned neutrophils with commensal and uropathogenic Escherichia coli biofilms

Maslennikova I.L., Nekrasova I.V., Orlova E.G., Gorbunova O.L., Shirshev S.V.


The aim of the work was to examine an interaction between neutrophils conditioned with chorionic gonadotropin, estriol, kisspeptin, leptin, ghrelin and commensal and uropathogenic Escherichia coli biofilms. Peripheral blood neutrophils isolated from healthy non-pregnant women in the first phase of the menstrual cycle (n = 8) were cultured in vitro for 1 hour together with hormones at concentration corresp onding to their level in the first and third trimester of pregnancy. An interaction of neutrophils with commensal E. coli TG1 and uropathogenic E. coli DL82 (UPEC) biofilms was assessed 1 hour later. The biofilm biomass, activity of myeloperoxidase and cathepsin G was measured spectrophotometrically on a microplate reader Synergy H1 (BioTec, USA). Neutrophils conditioned with chorionic gonadotropin (10; 100 IU/ml), estriol (2; 20 ng/ml) and leptin (10 ng/ml) were found to enhance their potential to destroy solely opsonized commensal E. coli biofilm, without affecting the UPEC biofilm. The biomass of non-opsonized biofilm of commensal E. coli TG1 decreased after interaction with neutrophils conditioned with estriol (2 ng/ml), kisspeptin (9.6 pM) and ghrelin (0.83 ng/ml). In contrast, non-opsonized UPEC biofilm was more destroyed by neutrophils exposed to low- vs. high-dose chorionic gonadotropin (10 IU/ml and 100 IU/ml, respectively) or control group. Myeloperoxidase secretion increased when UPEC interacted with neutrophils conditioned with estriol at concentration of 2 ng/ml. Comparing the two E. coli strains allowed to find that chorionic gonadotropin (10 IU/ml) and estriol (20 ng/ml) enhanced activity of neutrophil myeloperoxidase after interaction with UPEC biofilms to a greater extent than with E. coli TG1 biofilms. Estriol (20 ng/ml) and kisspeptin (9 pM) reduced activity of neutrophil cathepsin G after interaction with UPEC biofilms.

Russian Journal of Infection and Immunity. 2020;10(1):64-72
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An interaction of Zika virus envelope fragments with serum antibodies derived from subjects after flavivirus infections

Shanshin D.V., Bakulina A.Y., Kazachinskaia E.I., Pyankov S.A., Ilyichev A.A., Scherbakov D.N.


The causative agent of Zika fever (ZIKV) belongs to the genus Flavivirus of the family Flaviviridae. The flavivirus genus consists of more than 70 members. Based on virion structural organization and amino acid composition of proteins, this virus resembles other flaviviruses such as dengue (DENV), yellow fever and West Nile (WNV) posing a threat to human health. ZIKV is an arbovirus and may be transmitted by diverse mosquito species of the genus Aedes. It is believed that the main carriers are also able to transmit dengue virus, yellow fever virus as well as other flavivirus infections. In 1947, ZIKV was isolated for the first time from blood samples obtained from rhesus macaques inhabiting the Zika Forest (Uganda). Long time this virus was not considered as a dangerous to human pathogen, as Zika fever mostly occurs asymptomatically. However, analysis of Zika fever course in pregnant women unveiled a link between this disease and severe congenital disorders of the nervous system, including microcephaly, that allowed to deal with it as a dangerous infection thereafter. Rapid ZIKV spread outlined a number of problems faced by medical doctors, among which the main issue was the lack of assays for its virus-specific diagnostics. ZIKV displays a marked antigenic similarity with other flaviviruses. The majority of dengue-specific monoclonal antibodies binds to Zika virus. It is expected given the high degree of amino acid sequence similarity found for flavivirus polyprotein. Several antigens bearing ZIKV E surface protein fragments were constructed to assess an opportunity for conducting differential diagnostics for distinct flaviviruses based on detection of virus-specific antibodies. Vector plasmid pET32 was selected for producing recombinant antigens in E. coli cells. After creating constructs encoding the ZEa187 and ZEa40 proteins, the chimeric proteins were produced in amount necessary for performing ELISA with blood serum samples. Protein samples were prepared by isolating them from bacterial biomass via lysis followed by chromatographic purification. Blood sera obtained from human subjects recovered after Zika, Dengue and West Nile fevers were used to examined immunochemical properties of chimeric proteins. Human sera containing no antibodies against flavivirus types were used as a negative control. It was found that serum IgM class antibodies derived from patients with flavivirus infections demonstrated a high level of cross-reactivity by interacting with ZEa187 and ZEa40. Upon that, despite increment of mean specific interaction signal observed for such proteins and IgG of ZIKV sera, a marked cross-reactivity with the IgG of WNV and DENV sera was found. Thus, with some certainty it may be concluded that in immunochemical assays use of natural amino acid sequence specific to Zika virus surface protein as antigenic material does not allow to achieve high specificity for antibody detection.

Russian Journal of Infection and Immunity. 2020;10(1):73-82
pages 73-82 views

Anesthesia of laboratory animals in manufacturing of diagnostic and preventive biomedicines

Semakova A.P., Germanchuk V.G., Rogozhin V.V., Shavina N.Y., Ovchinnikova M.V., Kirilova T.Y., Livanova L.F., Belyakova N.I.


Preparations such as XilaVet, Zoletil 100 as well as Aeranne (Isoflurane) are successfully applied for animal anesthesia in veterinary practice. We assessed a possibility of using parenteral narcosis with Zoletil 100 in combination with muscle relaxant Xila for producer-rabbits involved in manufacturing of natural rabbit serum subsequently deployed for production of diagnostic serum and immunoglobulin preparations. Administration of preparations into auricular vein is easy to do, while animals are sedated immediately allowing for safe fixation on restraining table and causing no additional stress for biomodels. This type of narcosis provides for expected depth of anesthesia and its maintenance until the end of blood-letting procedure. Parameters characterizing the state of cardiovascular system due to anesthetic products remained within the permitted limits. These preparations do not reduce heart beat rate allowing for collecting sufficient blood volumes. Application of inhalation anesthesia with Aeranne in laboratory animals provides for the specified depth of anesthesia and its maintenance until the end of the whole procedure. However, it requires specialized equipment and highly trained personnel with appropriate skills. Usage of Xila as a mono narcosis is not recommended as exhibits weak analgesic effects and strong hypotensive activity by decreasing quantity of collected blood volume. It was found that anesthetics such as Xila, Zoletil 100, Aeranne did not affect specific activity of immune sera in case of total dehematizing procedure. Moreover, antibody titers were not declined throughout entire observation (12 months) period and complied with the requirements of regulatory documentation. In addition, a feasibility of replacing old-fashioned anesthesia method with diethyl ether for a combination of safer contemporary preparations of Zoletil 100 and Xila was demonstrated while manufacturing tableted chemical cholera vaccine in experimental series with suckling rabbits used at diverse stages of raw material verification during surgical interventions. Xila, Zoletil 100, and Aeranne examined by us had no impact on the amount of blood obtained from donor-animals, immunological properties of the sera and ready-to-use diagnostic preparations. Such drugs were safe for all-age animals that comply with the requirements to anesthesia of animal biomodels and producer-animals in manufacturing of immunobiological preparations. Thus, our study allowed to conduct experiments with laboratory animals in a more humane manner.

Russian Journal of Infection and Immunity. 2020;10(1):83-89
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Measures counteracting 2016 spread of vaccine-derived poliomyelitis virus type 2 in Russian Federation

Popova A.Y., Ezhlova E.B., Melnikova A.A., Morozova N.S., Mikhailova Y.M., Ivanova O.E., Kozlovskaya L.I., Eremeeva T.P., Gmyl A.P., Korotkova E.A., Baykova O.Y., Krasota A.Y., Ivanenko А.V., Yarmolskaya M.S., Kovalchuk I.V., Romanenko E.N.


Since April 2016 after global cessation of using trivalent oral poliovirus vaccine (tOPV) and switch to bivalent OPV consisting of polioviruses types 1 and 3 (the “switch”), any isolation of type 2 poliovirus has been regarded as an event of extreme importance requiring investigation, risk assessment and decision making. In 2016, 2 cases of isolated vaccine-derived poliovirus type 2 from healthy children was registered in Russia. Our study was aimed at on the assessing a risk of further spread of vaccine-derived poliovirus type 2 and provide measures for preventing its further spread based on epidemiological investigation and genetic characteristics of the isolated viruses. The cases were revealed within the surveillance program for poliomyelitis and acute flaccid paralysis syndrome conducted in the Russian Federation. The laboratory investigation was carried out in accordance with the algorithm adopted in the Russian Federation and recommended by the WHO standards: virus isolation on RD, L20B and Hep2C cell cultures, identification in the neutralization reaction, intratyping differentiation by using RT-PCR in real-time mode, sequencing of the poliovirus genome fragments encoding the VP1 protein. A risk assessment for spread of vaccine-derived poliovirus type 2 was performed in accordance with the WHO recommendations. There was uncovered a genetic relationship between virus strains isolated in September and December from unvaccinated Moscow resident boy (1 year old) who arrived from the Chechen Republic and from unvaccinated girl resident of the Chechen Republic (1 year old) with impaired humoral and cellular immunity. The virus strains were found to bear 10 and 13 genomic nucleotide substitutions, respectively, at the site encoding the VP1 protein compared with the Sabin type 2 vaccine strain that allowed to classify them as vaccine-derived polioviruses. In particular, both virus strains were shown to originate from the type 2 strain presented in the tOPV used shortly before the “switch”. Epidemiological investigation revealed family ties and probable contact between both children in the same premises. A series of organizational and vaccination measures was undertaken, as well as polio surveillance was strengthened in the region. No new type 2 polioviruses of vaccine origin were detected in the territory of the Chechen Republic during 18-month monitoring follow-up. The risk assessment of spread for vaccine-derived poliovirus type 2 in a region, Russian Federation as well as cross-boundary spread identified it as “low,” requiring no use of type 2 monovalent OPV. Such experience for countermeasures may be taken into account to oppose the risks before and after the global certification for poliomyelitis eradication.

Russian Journal of Infection and Immunity. 2020;10(1):90-98
pages 90-98 views

The antimicrobial susceptibility, resistance mechanisms and phylogenetic structure of S. Typhi isolated in 2005-2018 in the Russian Federation

Egorova S.A., Kuleshov K.V., Kaftyreva L.A., Matveeva Z.N.


Here we present current global epidemiological and microbiological trends for typhoid fever, as well as describe antimicrobial susceptibility and resistance mechanisms of S. Typhi. The data on examining 299 S. Typhi isolates collected in 2005—2018 in the Russian Federation were analyzed from the Russian S. Typhi Reference Center. It was found that S. Typhi population consisted of the isolates with different resistance phenotypes and mechanisms as well as genetic heterogeneity. Moreover, antimicrobial susceptibility was detected in as low as 10.4% S. Typhi strains, whereas 89.6% isolates showed fluoroquinolone resistance (including 7.3% high-level resistance) and 3.0% — multidrug resistance to am-picillin, chloramphenicol, trimethoprim/sulfamethoxazole, tetracycline and fluoroquinolones. All strains preserved susceptibility to extended-spectrum cephalosporins and azithromycin. Fluoroquinolone low-level resistance in S. Typhi was due to single nucleotide substitutions in the gyrA: Asp87Asn (78.7%) Ser83Tyr (5.0%) and Ser83Phe (3.2%). In addition, a plasmid-mediated low-level fluoroquinolone resistance (qnrS) was found in one isolate. In contrast, a fluoroquinolone high-level resistance in S. Typhi was due to accumulation of three single nucleotide substitutions in the genes gyrA (Asp87Asn+Ser83Phe) andparC (Ser80Ile). In multidrug resistant S. Typhi isolates, pHCMl plasmids of incompatibility group IncHI1B(R27) (consisted of blaTEM.1, catA1, dfrA7 and tetB) and single nucleotide substitutions Ser83Tyr or Asp87Asn in gene gyrA were detected. The data of phylogenetic reconstruction based on the analysis of core singlenucleotide variations among examined and previously sequenced S. Typhi genomes, demonstrated that more than 80.0% of S. Typhi isolated in Russia were referred to the Asian genotype as they belonged to subclade 4.3.1 (by Wong et al.) or dominant H58 clade (H58 haplotype by Roumagnac et al.). More than 60.0% isolates in this dominant phylogenetic group possessed a fluoroquinolone low-level resistance due to gyrA Asp87Asn. Less than 20.0% of S. Typhi strains isolated in Russia phylogenetically belonged to the subclades other than 4.3.1 (non-H58) and differed from the major S. Typhi population by lacked antibiotic resistance or exerted fluoroquinolone resistance due to gyrA Ser83Phe. The study data allowed to expand our understanding on genetic diversity in S. Typhi strains isolated recently and pinpoint features of phylogenetic structure for S. Typhi population in the Russian Federation.

Russian Journal of Infection and Immunity. 2020;10(1):99-110
pages 99-110 views

Detection of meningococcus, pneumococcus, Haemophilus influenzae, and group A streptococcus DNA in pediatric adenoid bioptats

Kombarova S.Y., Bichucher A.M., Soldatsky Y.L., Yunusova R.Y., Skirda T.A., Martynenko I.G., Golovina L.I., Edgem S.R., Severin T.V., Melnikov V.G.


Meningococcal, pneumococcal, streptococcal A and Haemophilus influenzae infections are manifested in different clinical forms, ranging from bacterial carriage to generalized life-threatening conditions. However, a connection between bacterial carriage and disease development has not been fully explored. A PCR assay was performed with adenoid biopsy samples collected from 112 children after planned adenotomy to detect Neisseria meningitidis, Streptococcus pneumoniae, Streptococcus pyogenes, H. influenzae carriage. A DNA specific to at least one of the four studied microbial species was found in 104 samples (92.86%) so that: meningococcal DNA was detected in one sample (0.9%), pneumococcal — in 98 (87.5%), H. influenzae — in 19 (16.96%), and streptococcal A — in 42 (37.5%) samples. However, none of these species was found in 8 children (7.14%). A sole S. pneumoniae was detected in 54 samples (48.2%), whereas S. pyogenes — in 5 samples (4.5%). Moreover, two bacterial species were simultaneously as follows: N. meningitidis and S. pneumoniae — in 1 sample (0.9%), S. pneumoniae and H. influenzae — in 7 samples (6.3%); H. influenzae and S. pyogenes — in 1 sample (0.9%); S. pneumoniae and S. pyogenes — in 25 samples (22.3%). A triple combination consisting of S. pneumoniae, H. influenzae and S. pyogenes bacteria were detected together in 11 patients (9.8%). Meningococcal serogrouping revealed no connection with any of the 6 most common global serogroups responsible for epidemic incidence rise (A, B, C, W-135, X, Y). A clear tendency for prevalence of S. pyogenes DNA in adenoid pediatric biopsies in children diagnosed with “Adenoids and tonsils hypertrophy” vs. “Adenoids hypertrophy” was observed. It is noteworthy, a high relative prevalence of pneumococcal carriage (87.5%), found by us was of special importance. Pediatric carriers serving as a reservoir for virulent pneumococcal species pose a threat both for themselves and surrounding people. Thus, PCR-based data of adenoid biopsies may be a promising approach for future studies, as a potential to identify live viable but nonculturable bacteria in clinical specimens will contribute to a more accurate assessment of carriage rate of meningococci, pneumococci, H. influenzae and group A streptococci.

Russian Journal of Infection and Immunity. 2020;10(1):111-120
pages 111-120 views

The importance of pathogenicity factors of some Streptococcus spp. and Klebsiella spp. in determining their etiological role in the inflammatory processes of the respiratory tract

Kraeva L.A., Kunilova E.S., Burgasova O.A., Hamdulaeva G.N., Danilova E.M., Bespalova G.I.


Together with the known pathogens of inflammatory processes of the respiratory tract in clinical practice are often found representatives of Streptococcus and Klebsiella, previously considered commensals of the mucous membranes of the upper respiratory tract. The exchange of genetic information facilitates the transfer of virulence factors between strains not only within the species but also within the genus. In such cases, the acquisition of virulence genes by nonpathogenic species from representatives of pathogenic species contributes to the manifestation of previously not typical properties. Therefore, the aim of the research was to study the virulence of opportunistic Streptococcus spp. and Klebsiella spp. in inflammatory processes of the respiratory tract and substantiate their etiological role in the development of the disease. We studied 220 strains of Streptococcus spp. and 97 strains of Klebsiella spp., isolated from patients with inflammatory processes in the respiratory tract and from healthy individuals. Strains of Streptococcus spp. were investigated for the presence of virulence genes: sagA, lmb, fapl, ply, lytA. Strains of Klebsiella spp. were examined for the presence of virulence genes: MrkD, magA, kfu. The phenotypic marker of lmb gene expression in Streptococcus and MrkD gene in Klebsiella was the indicator of adhesion of isolated strains to buccal epithelial cells. Expression of the fapl gene was evaluated in a phenotypic biofilm formation test. In individuals with upper respiratory tract inflammation, the most common types of strepto -cocci were: S. mitis, S. anginosus, and S. oralis. Strains of these species isolated from inflammatory processes in the upper respiratory tract had 2—4 times greater adhesiveness than strains isolated from healthy individuals. Phenotypic determination of the ability to biofilm formation showed that strains of Streptococcus containing the fapl gene formed a dense biofilm in contrast to strains without the fapl gene. K. oxytoca strains isolated from people with sinusitis had mrkd, magA, and kfu virulence genes that are characteristic of K. pneumoniae strains. In phenotypic tests, it was found that the value of the adhesion index in K. oxytoca strains isolated from patients is 4 times higher than in strains of this species isolated from healthy individuals. Thus, to confirm the etiological role of an opportunistic microorganism in the development of the infectious process, it is necessary to be guided by data on the genetic and phenotypic markers of virulence of the isolated strain.
Russian Journal of Infection and Immunity. 2020;10(1):121-128
pages 121-128 views

Level of measles herd immunity assessed in hospital medical workers within a framework of the state measles elimination program

Kostinov M.P., Filatov N.N., Zhuravlev P.I., Gladkova L.S., Polischuk V.B., Shmitko A.D., Pakhomov D.V., Khromova E.A., Vasilyeva G.V., Tikhonova I.A., Ryzhov A.A., Blagovidov D.A., Kostinova A.M.


Within a framework of the state measles elimination program, in April, 2018 a level of measles herd immunity was assessed in 1899 Moscow hospital medical workers aged from 19 to 69 years and older. All subjects enrolled in the study were vaccinated against measles or recovered after measles infection. Serum samples were collected from subjects and examined by ELISA for measles IgG antibodies with the Vector-Best IgG-measle test system (Russia). It was found that 278 (14.6%) and 1621 (85.4%) subjects were seronegative (< 0.18 IU/mL) and seropositive (> 0.18 IU/ml), respectively. Age-related group distribution of 1855 serum samples revealed that percentage of seronegative subjects was in: aged 19—23 years was -38.5%; 24-28 and 29-33 years - 22.2%; 34-38 years - 27.5%; 39-43 years - 25.8%; 44-48 years - 16.8%; 49-53 and 54-58 years — 8.6% and 8.3%, respectively; 59-63 years old — 4.9%; 64-68 and over 69 years old — 0%. Moreover, mean level of measles IgG antibodies increased proportionally to age of medical workers from 0.58 IU/ml (19-23 years) to 2.94-2.72 IU/ml (64-68 and over 69 years). The data obtained indicate that a cohort of measles susceptible subjects (from 38.5% to 16.8%), respectively, is identified among young and middle age (from 19 to 48 years) individuals. It is assumed that two-dose measles vaccination in childhood does not contribute to the long-term preservation of protective levels of measles antibodies, thereby justifying a need to administer a three-dose measles vaccine.

Russian Journal of Infection and Immunity. 2020;10(1):129-136
pages 129-136 views

Formation of humoral and cellular immunity to measles vaccine in adults

Toptygina A.P., Andreev Y.Y., Smerdova M.A., Zetkin A.Y., Klykova T.G.


Despite adherence to the policy of mass measles vaccination in the majority of countries, this infection still remains far from being fully eradicated. Measles outbreaks are reported worldwide, when the vast majority of cases are recorded in subjects of 18—35 years of age. Studies on assessing measles IgG antibody level in different regions of Russia reveal increased percentage of measles seronegative subjects among young adults. Current study was aimed at investigating formation of humoral and cellular immunity after measles vaccination in seronegative adults aged 18 to 30 years old. There were enrolled 50 measles seronegative healthy volunteers aged 18 to 30 years old. Level of anti-measles IgM and IgG antibodies was measured by ELISA (Vector-Best, Russia). Subclasses of measles specific IgG antibodies were analyzed by ELISA, by replacing IgG conjugate for IgG1, IgG2, IgG3, IgG4 conjugates, whereas measles specific IgA antibodies were estimated by ELISA with IgA conjugate (Polygnost, Russia) at a concentration of 1 μg/ml. Antibody avidity was assessed by ELISA (Euroimmun, Germany). Cell-mediated measles immunity was estimated by CD107a surface expression on CD8hi T cell subset stimulated by measles virus-derived antigens. A specific cellular response to measles antigens before vaccination was detected in 50% of examined subjects, whereas 40% samples showed no signs of cellular immune response, with 10% of remaining cases described as equivocal. It was found that 6 weeks after vaccination all vaccinated subjects developed measles specific IgG antibodies at protective level reaching 1.33 (0.85—1.82) IU/ml [Me (LQ—UQ)]. Anti-measles IgA antibodies were of 0.655 (0.423—1.208) IU/ml [Me (LQ—UQ)]. However, no measles specific IgM antibodies were detected 6 weeks after vaccination. In addition, primary type of immune response (dominant low-avidity anti-measles antibodies IgG3 subclass) to measles vaccination was observed in 24 out of 50 subjects, whereas 26 subjects developed secondary type of immune response (high-avidity anti-measles antibodies dominated by IgG1 subclass). A measles specific cellular immune response was observed in 47 of the 50 examined subjects, and in 3 volunteers it was equivocal. Further analysis revealed a cohort of subjects who were not vaccinated against measles (18 subjects), although 60% of them provided medical record on previous dual measles vaccination occurred in childhood. Another cohort consisted of subjects who had medical record of measles vaccination in childhood (32 subjects), but lost protective measles antibodies produced by plasma cells (23 subjects), and memory T cells (3 subjects), or measles antibodies and memory B cells (6 subjects) over time. Such pattern evidences that measles-specific cellular and humoral arms immune responses were developed and maintained independently of each other.

Russian Journal of Infection and Immunity. 2020;10(1):137-144
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Features of local immunity in women with endometriosis and genital infection

Zaynetdinova L.F., Telesheva L.F., Koryaushkina A.V.


Introduction. External genital endometriosis is an inflammatory estrogen-dependent disease characterized by implantation and proliferation of endometrial tissue outside the uterus, accompanied by increased production of proinflammatory cytokines, prostaglandins, components of the complement, hydrolytic enzymes, increased angiogenesis and anomalies of ectopic endometrium. According to implantation theory, external genital endometriosis develops from viable endometrial cells transferred retrogradely through the fallopian tubes to the abdominal cavity during menstruation, while a disturbed local immunity is an important factor in its pathogenesis. Genital pathogens may be involved in the formation of the immune environment of the peritoneal cavity in women with endometriosis.

Purpose. To study the peculiarities of local immunity in women with external genital endometriosis and genital infection pathogens.

Materials and methods. 159 women with external genital endometriosis were examined. The total number of leukocytes, the absolute and relative number of viable cells, counts of neutrophils, macrophages and their functional activity, the level of IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IFNα, IFNγ, TNFα in the peritoneal fluid were evaluated. The study of local immunity was performed in women with endometriosis, stage 1—2 and 3—4, depending on detected genital pathogens. Chlamydia trachomatis, Ureaplasma spp., Mycoplasma genitalium, HSV1,2/CMV, high carcinogenic risk HPV were analyzed by using PCR in samples collected from the endometrium, peritoneal fluid, and endometrioid heterotopies. Statistical processing was performed by using the IBM SPSS Statistics Version 22.2 statistical analysis software package.

Results. In the presence of HPV and Ureaplasma spp. in women with endometriosis, stage 1—2, the decreased functional activity of peritoneal neutrophils and macrophages was found. At 3—4 stage, a correlation analysis revealed that detected HPV and Ureaplasma spp. obtained increased both pro-inflammatory and anti-inflammatory cytokines in the peritoneum. However, the higher activity of Th-2 cells in the peritoneal fluid secreting IL-4 and IL-10 and suppressing cellular immunity, was observed in HPV-positive samples. In addition, HPV also correlated with a decreased IL-2 and IL-4 levels.

Conclusions. The most prominent changes in the immunological parameters from peritoneal fluid samples were observed in case of detected genital infection pathogens, particularly HPV. Thus, immune disturbances emerged upon bacterial and viral pathogen detection may contribute to the implantation of endometrial cells in the pelvic organs and disease progression.

Russian Journal of Infection and Immunity. 2020;10(1):145-158
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Genotyping of tick-borne encephalitis and Kemerovo viruses in taiga ticks collected in the Komi Republic

Kartashov M.Y., Mikryukova T.P., Krivosheina E.I., Kuznetsov A.I., Glushkova L.I., Korabel`nikov I.V., Egorova Y.I., Ternovoi V.A., Loktev V.B.


Over the last years, an increasing rate of ixodes tick bites has been registered in the northern regions of the European Russia. In addition, the number of subjects request medical assistance due to tick bites has been dramatically increased in the Komi Republic. In addition, incidence of tick-borne encephalitis was also increased particularly starting since 2009. However, highly limited data on pathogen genetic diversity related to viral tick-borne infections in this region are currently available. Taiga ticks (Ixodespersulcatus) collected from the Komi Republic southern and central part vegetation were examined to identify and genotype tick-borne viruses. Individual ticks were used to identify by RT-PCR viral RNA coupled to tick-borne encephalitis and Kemerovo viruses. Viral genome fragment sequencing allowed to unambiguously identify these viruses. It was found that viral RNA tick-borne encephalitis was detected in 6.8±1.2% individual ticks. Moreover, tick-linked isolate genotyping based on analyzing E protein gene fragment nucleotide sequence derived from tick-borne encephalitis discovered that 35% and 65% isolates belonged to the Far Eastern and Siberian subtype, respectively. In addition, subsequent phylogenetic analysis demonstrated that at least four variants of the Siberian and Far Eastern subtypes of tick-borne encephalitis virus were detected, which were close to the viruses circulating in the Urals and Siberia. In contrast, prevalence of Kemerovo virus in taiga ticks was 0.8±0.2%. Sequencing of Kemerovo virus RNA-dependent RNA polymerase gene fragment showed around 94% homology with the remainder of the Kemerovo virus strains. Phylogenetic analysis of the Kemerovo virus genome fragments demonstrated at least two subtypes circulating in the Komi Republic. Thus, it was suggested that tick-borne encephalitis virus was introduced relatively recently from the Urals and Siberian region into the natural foci of the Komi Republic. Moreover, genetic differences found in Kemerovo virus strains presume for them a longer lasting evolution throughout the natural foci of this region. In addition, a potential role for birds and their ticks in rapid spreading of viral tick-borne infections in the Komi Republic is also discussed. Thus, the data on genetic diversity of the viral agents related to tick-born encephalitis and Kemerovo fever may be useful for improving their diagnostics, prevention and treatment in the Komi Republic.

Russian Journal of Infection and Immunity. 2020;10(1):159-166
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Rat peripheral blood leukocyte subset composition, hemogram, lymphoid organ and body morphometry after exposure to biologically active substances derived from Hirudo verbana saliva

Aminov R.F., Frolov A.K., Fedotov Y.R.


Medical community has noted that the prevalence of allergic diseases by steadily tends to rise resulting from using synthetic drugs ecological catastrophe. In this regard, more and more attention is increasingly being paid to natural therapeutic approaches, one of which is based on applying hirudotherapy. There were used 40 pubescent outbred female rats and their 200 pups born during experiment. In particular, female rats underwent leeching in the subscapular region 2 weeks before and 2 weeks after mating by applying medical leeches weighing 400 ± 10 mg. Next, relevant progeny was examined at day 1, 15, 30, 45, and 60 after birth, whereas female rats– after weaning. Experiment was designed to assess diverse parameters in accordance with the age-related rat development: newborn pups – 1-5 days old, day 6-21 – suckling period, day 22-50 – onset of puberty, day 60 onward – puberty. After measuring body morphometric parameters, female rats were sacrificed by decapitation under ether narcosis on day 60, whereas rat pups – at various time points. followed by autopsy and collecting blood sample into a sterile centrifuge tube by using 2% Spofa crystalline heparin (8:1) to be further examined by standard assays: morphometry of rat body, spleen and thymus; measuring total leukocyte count; CBC with differential; RBC; hemoglobin level; color index. Statistical data processing was performed by calculating arithmetic mean, error of arithmetic mean, standard deviation by using SPSS version 21.0 and Microsoft Office Excel 2010 software. Significance of differences was estimated by using Student's t test, and set at p≤0.05. Our study demonstrated medical leech saliva components applied during hirudolotherapy exerted an immune-augmenting effect of on morphometric body, thymus and spleen parameters. Moreover, starting from day 1, total leukocyte count, RBC, and hemoglobin level were increased in the experimental group. Moreover, we convincingly demonstrated a stimulatory effect of medical leech saliva components on histogenetic reactions at various ontogenetic stages in both female rats and their progeny. In the former, such morphogenetic effect was maintained for more than 70 days after the last leeching: on week 2 after mating and 30 days after delivery. Changes in morphological and hematological evidence about enhanced morphogenetic function of immune system in response to saliva-derived biologically active substances released by medicinal leeches.
Russian Journal of Infection and Immunity. 2020;10(1):167-174
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Prevalence of Borrelia burgdorferi sensu lato genetic markers in blood-sucking ticks in suburban park zones in Saint Petersburg

Panferova Y.A., Vaganova A.N., Freylikhman O.A., Tretyakov K.A., Medvedev S.G., Shapar’ A.O., Tokarevich N.K.


Tick-borne bacterial and viral infections are widespread in middle latitudes of the Northern hemisphere. Natural foci of such infections coincide with geographic areas inhabited by ixodid ticks. Ixodid tick-borne borreliosis is a pressing issue for some territories of Russia, especially for the North-Western Federal District and St. Petersburg megalopolis as well as adjacent areas of the Leningrad District, where people may become infected after tick bite in recreational zones in suburban park areas. Currently, very few publications regarding prevalence of tick-borne pathogens in St. Petersburg area are available. In our study, questing ticks flagged in park zone (northern coast of Finnish Gulf, Kurortny District) were examined with PCR for carriage of pathogenic B. burgdorferi sensu lato complex. In addition, samples positive for Borrelia DNA signal were further genotyped with species-specific primers against rpoBgene fragment. It was found that Ixodes persulcatus dominated in this area. Prevalence of Borrelia burgdorferi s.l. complex comprised 9.33%. Genospecies B. afzelii and less frequently B. garinii were detected. A mixt-infection with two Borel-lia species was detected in one sample. Interestingly, all Borrelia-infected ticks belonged to I. persulcatus suggesting a closer association for certain species in «pathogen-vector» system. Our findings are essential in investigating distribution of ixodid borreliosis foci in St. Petersburg and suburbs, obtaining new data regarding epidemiology, diagnostics, treatment and prevention of this infection. It is noteworthy than prevalence of pathogenic Borrelia spp. vs. tick-borne encephalitis virus in vectors was higher thereby accounting for its higher morbidity. Comparing our data with those published elsewhere by European researchers allows to note that prevalence of pathogenic Borrelia spp. in ticks varies broadly in diverse geographic regions. It is necessary to take into consideration that prevalence of Borrelia markers achieves ~10% in ticks given frequent attendance of park areas near St. Petersburg that point at risk of developing bor-reliosis in recreational zones.

Russian Journal of Infection and Immunity. 2020;10(1):175-179
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Complement activation lectin pathway (mannose-binding lectin and ficolin) genes polymorphism as the risk factor of CagA positive chronic Helicobacter pylori infection in adolescents

Tereshchenko S.Y., Smolnikova M.V., Zobova S.N.


Currently, features of the host immune response against Helicobacter pylori (Hp) both regarding establishment of chronic carriage after primary infection as well as a role of impaired immune and inflammatory response in the mechanisms of developing erosive-ulcerative lesions remain poorly investigated. Only few molecules are known to activate the complement activation lectin pathway including human ficolins and mannose-binding lectin (MBL). A substantial part of the human population bears an intrinsically low MBL and ficolin production level and/or low functional activity due to the carriage of various MBL2 genetic variants potentially elevating susceptibility to a more severe course of a wide range of infectious diseases. It has been shown that the MBL2 gene polymorphisms are associated with a risk of developing in Hp-infected patients more severe gastric mucosal atrophy and gastric cancer risk. An impact of the MBL2 and L-ficolin (FNC2) gene variants on Hp infection rate in Russia has not yet been examined in full detail. In our study we enrolled 93 Caucasian adolescents (aged 12-17, Krasnoyarsk, Siberia, Russia) to test for serum anti-Hp-CagA antibodies. Additionally, 203 newborn dried blood spot specimens born in Krasnoyarsk, Russia, were used as a population control sample. Genotyping of allelic MBL2 and FCN2 gene variants was performed by using RFLP approach to examine the following polymorphic regions: rs11800451 and rs1800450 (MBL2), rs17549193 and rs7851696 (FCN2). Carriage of the rare allele in the polymorphic region rs1800450 of the MBL2 gene and the homozygous for the rare allele T of polymorphism rs17549193 in FCN2 gene was associated with an increased risk of CagA seropositivity (OR = 2.36 (1.03-5.4), p = 0.04 and OR = 5.69 (1.08-29.99), p = 0.04, respectively) shown before to be associated with low plasma concentrations and/or low functional activity of mannose-binding lectin and L-ficolin. In contrast, such genetic variants in the newborn population cohort had an intermediate prevalence further confirming the Caucasoid identity of the samples and an unbiased inclusion of subjects in the main test groups. Thus, we suggest that the primary MBL and L-ficolin deficiencies are associated with a higher risk of CagA positive Helicobacter pylori chronic infection in adolescents seemingly accounted for by alterations in lectin-mediated complement activation and opsonization especially in case of CagA positive bacterial strains.

Russian Journal of Infection and Immunity. 2020;10(1):180-186
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Influence of Helicobacter pylori on cytokine regulation in chronic atrophic gastritis

Smirnova O.V., Sinyakov A.A.


At present, the level of Helicobacter pylori infection is determined by geographic area, gender and age of the examined individuals, and can reach up to 95% of the total population. Environmental adaptation of H. pylori is exhibited in its ability to adhere to the gastric mucosal epithelium and modulated expression of its own virulent factors. Current concepts implicate that H. pylori can survive inside epithelial cells, evading host immune response. Cytokines are produced by immune cells and act to regulate its major stages. A cytokine cascade launched after Helicobacter pylori infection triggers immune reactions, progression of chronic inflammatory and destructive processes in the gastric mucosa. The role of cytokines in precancerous diseases of the stomach is ambiguous because, on the one hand, they activate immune response aimed at eliminating the pathogen, whereas on the other hand, they do contribute to the disease progression. The aim of our study was to examine profile of some cytokines and features of cytokine regulation in H. pylori-infected middle-aged males with chronic gastritis (CG) as well as chronic atrophic gastritis (CAG). In patients with CG with H. pylori, CAG and CAG with H. pylori, an increase in the cytokine IL-2 was observed that might contribute to augmented damaging effect of cytotoxic lymphocytes, as well as implementation of antitumor effect. CAG with H. pylori was featured with IL-8 hyperproduction, which resulted in increased absolute numbers of band neutrophils in peripheral blood and their decreased phagocytic activity evidencing about altered host defense mechanisms. There was increased amount of IFNy involved in recognition of malignantly transformed cells and upregulated expression of the major histocompatibility complex molecules on antigen-presenting cells. In patients with CG with H. pylori and CAG with H. pylori, production of IL-4 was increased, which might serve as a contributing factor to the chronicity of H. pylori-associated diseases. Overproduction of type 1 and type 2 cytokines indicates about activated Th1 and Th2 type immune reactions in H. pylori-associat-ed CG. A potent pro-inflammatory cytokine cascade triggers inflammatory changes in gastric mucosa with developing neutrophil infiltration and lymphocyte activation. Damage and death of epithelial cells upon inflammation form erosive and ulcerative defects, or changes manifested as gastric mucosal atrophy, metaplasia and neoplasia. The data obtained may be used as additional diagnostic criteria in early diagnostics of precancerous stomach diseases.

Russian Journal of Infection and Immunity. 2020;10(1):187-192
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Examining Echinococcus multilocularis infection in some Midland Russia predatory animal species

Andreyanov O.N.


Commercially exploited predator animal species are considered as a final host for multiple biohelminths posing a threat both to human and other animals. Fight against pathogens of dangerous helminthozoonoses should be based on combining efforts of scientific and practical centers, various state departments, executive authorities, law enforcement authorities as well as country residents. Examining parasitic fauna in commercially exploited predator animals is of special priority in the Midland Russia with high population density, wherein people have been engaged in hunting closely contacting both with fur animals as well as domestic pets (dogs, cats). Alveococcosis is a natural focal disease caused by Echinococcus multilocularis. The study was aimed at examining dynamics of E. multilocularis recording in the Midland Russia commercially exploited predator animals. 2007—2018 Cestode spread was examined. A research material for (corpses, carcasses, body and tissue fragments) was obtained hunting reserves located in the Vladimir, Nizhny Novgorod, Moscow, Tver, Oryol and Bryansk regions of the Midland Russia as well as the Republic of Karelia. Complete or partial helminthological autopsy carried out in accordance with K.I. Scriabin technique (1928) was performed in 262 animals, including 193 common red foxes, 28 domestic and 16 raccoon dogs, 16 domestic cats, 6 wolves, 2 brown bears and one lynx. It was shown that cestodes E. multilocularis was found in 46 foxes (23.8%), 3 raccoon dogs (18.7%), 3 wolves (50%) and one domestic dog (3.6%). Moreover, the peak tapeworm prevalence in carnivorous animals was noted for foxes and raccoon dogs in 2010—2011 (42.4%), 2011— 2012 (37.1%) and 2012—2013 (42.1%). On the other hand, no tapeworm invasion in carnivores was noted during 2009—2010 and 2013—2014 sports hunting seasons. However, a causative agent of alveococcosis is routinely detected in the Ryazan and Vladimir regions. The prevalence of invasion in animals differs in foxes, raccoon dogs, wolves ranging from 12 to 40,000, in raccoon dogs — from 37 to 112, in wolves — from 12 to 318 tapeworms per animal, and in domestic dog reaching 19 worms per animal. The data of 2007—2018 personal studies point at spread of alveococcosis foci in the Midland Russia.

Russian Journal of Infection and Immunity. 2020;10(1):193-196
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