REVIEWS
Marburg fever is an acute natural-focal disease characterized by severe course, hemorrhagic syndrome, high level of contagiousness and lethality. The causative agent of the disease is the RNA-containing virus belonging to the family of filoviruses (Filoviridae). The main problem faced by doctors and scientists involved in the fight against Marburg fever is the lack of vaccines and preventive drugs against this disease. The development of effective vaccines against filovirus infection is relevant for protecting the population living in natural foci and medical personnel during epidemic outbreaks, as well as for ensuring safe research work in BSL-4 laboratories. In this regard, this review considers biomodels suitable for studying the pathogenesis of filovirus infections, preclinical studies of specific activity and harmlessness of prototype Marburg virus vaccines and variants of these vaccines.
We analyzed the data on availability and usage of mobile laboratories of biological expertise for indication and identification of pathogenic biological agents in foreign countries and in the Russian Federation. We outlined the major types of mobile units that exist abroad and in Russia. Key stages of evolution in design and deployment of mobile laboratories in the network of plague control institutions of the Rospotrebnadzor were described, as well as the broadening of the range of their use in Russia. We assessed operational use of the Russian mobile laboratories, both in Russia and abroad, in the provision of sanitary-epidemiological welfare during mass events, disaster management, and response to epidemic manifestations of particularly dangerous infectious diseases. Major trends in implementation of mobile units of biological expertise in Russia were identified. We addressed their usage in various State Programs on assistance to partner-countries in the matters of International Health Regulations (2005) implementation, control over dangerous infectious diseases. Advanced inventions – Second generation modernized mobile complex of the specialized anti-epidemic teams, mobile laboratory for monitoring and diagnostics, and airmobile anti-epidemic complex – were discussed.
The literature review focuses on epidemiological aspects of the spread of particularly dangerous mycoses across the world (coccidioidomycosis, histoplasmosis, blastomycosis, paracoccidioidomycosis). Forecast of morbidity rates for the next few years is provided too. Out of all endemic mycoses, coccidioidomycosis, endemic for North America regions, poses the most dangerous threat. In case of the infection, complications are most likely to arise, including the dissemination of the process in immunocompromised persons. Histoplasmosis is also classed as particularly dangerous mycosis. It affects both humans and animals. It is endemic for North, Central and South America, as well as Asia and Australia. The most studied endemic areas of infection with blastomycosis are in the territory of North America, while paracoccidioidomycosis is endemic for Latin America countries. Analysis of academic publications on particularly dangerous mycoses over the last three years testifies to the increase in their morbidity rates around the world. This situation is associated, primarily, with the increment in the number of immunocompromised subjects. An important stage in the improvement of the agent diagnostics is introduction of advanced methods for early diagnostics of mycoses, in particular, molecular-genetic and genome sequencing tools. It could also allow for the detection of patients beyond the limits of endemic foci.
Chiroptera is one of the largest in numbers orders of mammals which can take on the role of natural host and vector of various viruses, bacteria, and pathogenic fungi. Over the period of 2007–2013, 248 new viruses pertaining to 24 families were detected in chiropterans. Lately, a range of novel infections that provoked severe diseases in humans were associated with bats-carriers. Presently they are viewed as a potential reservoir of Ebola, Marburg, and Hendra viruses, severe acute respiratory syndrome agents, as well as many other lethal diseases. Chiropterans started drawing particular attention after establishment of the fact that they are involved in circulation of ebolavirus Zaire and possibly participate in the formation of natural foci of this infection. Currently chiropterans are considered to be natural reservoirs of ebolavirus Zaire and some other filoviruses (Filoviridae). Accept from filoviruses, other significant for public healthcare viruses were isolated from chiropterans on the African continent – lyssaviruses (Rhabdoviridae, Lyssavirus), henipaviruses (Paramixoviridae, Henipavirus), and coronaviruses (Coronaviridae, Alphacoronavirus, Betacoronavirus) that can also circulate among chiropterans in West Africa. The data available from literature sources on dissemination of chiropterans in the territory of the African continent, their species diversity, peculiarities of ecology and behavior are analyzed in this paper. The information on the infections for which chiropterans can serve as potential reservoirs is also provided. Specifics of interaction between the population residing on African continent and bats of different species are described too. The review is devoted to the assessment of results of studies on population, ecological, and epidemiological factors contributing to maintenance of circulation of a number of dangerous for humans viruses (filoviruses, lyssaviruses, henipaviruses, and coronaviruses) among African chiropterans. The need for further investigation of the mentioned factors affecting chiropteran populations in the Republic of Guinea is substantiated.
The paper presents the data on the assessment of the demand for heterologous drugs and highlights the need for their use in practical healthcare. Currently, 15 heterologous immunoglobulins and sera are registered in the Russian Federation. Nine of them are against bacterial and viral infections (anthrax, diphtheria, tetanus, botulism, rabies, anti-gangrenous), one – against snake venom, five other – anti-thymocyte immunoglobulins produced by domestic and foreign manufacturers. Analysis of the data has demonstrated that anti-rabies immunoglobulin, anti-diphtheria and anti-botulinic sera, A, B and E type are the most in-demand. Production of other therapeutic drugs from this group, for instance, anti-gangrenous serum, tends to decline. Adequate provision of medical curative and preventive institutions with these preparations is a significant element in timely treatment of infectious diseases such as anthrax, diphtheria, tetanus, botulism, rabies, as well as snake bites. In prophylaxis and treatment of certain diseases (emergency aid in case of anthrax, rabies, venomous snake bites) heterologous preparations still oftentimes do not have an alternative. The key problem in regulation of heterologous preparation circulation is absence of quality, efficacy and safety criteria applicable to other immunobiological preparations. Development of unified requirements to standardization of heterologous sera and immunoglobulins of various specificity, principles of efficacy and safety evaluation is necessary for harmonization of current guidelines on medical use. Earlier elaborated by WHO approaches to heterologous sera to venoms of snakes can be used for monitoring and harmonization of normative legal documents on the improvement, evaluation of quality, efficacy and safety of alternative drugs being in circulation in the pharmaceutical market of the Russian Federation.
ORIGINAL ARTICLES
Objective of the study was to test the nutrient medium based on the enzymatic hydrolysate of corn extract condensed for a scaled production of live plague vaccine and to check the quality of the obtained batches against the specified parameters. Materials and methods .A dense nutrient medium based on corn extract was used to grow biomass in the process of live plague vaccine production. The quality parameters of the vaccine preparation obtained were studied by the regulated methods set forth in the regulatory documentation. Results and conclusions. The vaccine was monitored at all stages of its manufacture, including control of the finished dosage form, in strict accordance with the approved regulatory documentation. All the experimental production series complied with the specified indices. Approbation of the production cycle environment for live plague vaccine manufacturing showed efficiency of the conditions and the possibility of environment’s application in the industrial production of the preparation.
Central-Caucasian natural plague focus was permanently epizootically active since its discovering in 1971 till 2007. Inter-epizootic period has been in progress since 2008. It was not possible to isolate agent strains from field material. Therefore a forecast for focus activation is a relevant task, especially against the background of registered plague cases in humans in 2014–2016. Objective of the study was to create a forecasting model for quantitative prediction of possible activation or maintenance of inter-epizootic period. Materials and methods. We used archival data of Kabardino-Balkar Plague Control Station: journals of rodents’ autopsy, annual reports on epizootiological surveillance, meteorological data from meteostation “Kislovodsk” over the period of 1989–2017, and our epidemiological data for the period 2010 to 2017. We applied Spearman nonparametric correlation analysis, regression analysis, including principal component method, quarterly analysis, and inhomogeneous sequential pattern recognition procedures for statistical processing. Results and discussion. We have designed statistical model which provides for forecasting of plague focus epizootic activity proactively, a year in advance and 99 % probability or higher. The model was tested on retrospective data over the course of 7 years. All predictions were correct. The operational forecasts from 2015 to 2017 proved right too. However there is a possibility of fast changes in the ecology system conditions of the Central-Caucasian natural plague focus because of the global warming. Thereby the forecasting model will be annually checked for informative value of the predictors and, if necessary, adjusted accordingly.
Objective – study of biological and molecular-genetic properties of Bacillus anthraciscultures isolated in the supervised Siberian and Far Eastern territory between 1959 and 2013. Materials and methods. 39 B. anthracisstrains isolated from different specimens in 11 Siberian and Far Eastern constituent entities during epizootic and epidemic complications in terms of anthrax and monitoring of the soil foci were studied. The strains were examined using 16 culturalmorphological and 23 biochemical tests, for virulence, plasmid content, 15 VNTR- and 13 SNP-loci. Results and conclusions. Phenotypic and considerable genotypic heterogeneity of B. anthracisstrains found in the supervised territory was demonstrated. It was determined that 87,2 % of the isolates possessed typical cultural-morphological and biochemical properties. Twenty VNTR-profiles and three canonical SNP-clusters belonging to two global genetic branches A and B were revealed by means of molecular-genetic typing. The data can serve as a genetic marker in the investigation of anthrax cases, potential bioterrorist acts and evaluation of epizootic activity of stationary hazardous as regards anthrax areas in the specified administrative territory. The database «Biological properties of Bacillus anthracisstrains isolated in Siberia and Far East» was generated on the basis of systematization and analysis of the data concerning the origin, biological, molecular-genetic properties of the isolates. The Certificate of State Registration was also received. The database structure is replenishable and can be expanded if new technologies and methods are applied.
Objective of the study was the development of immune-enzymatic monoclonal test-kit for detecting glanders and melioidosis agents. Materials and methods. We used microbial cultures and hybrid cell lines obtained from the collection of the «48th Central Research Institute» of the Ministry of Defense of the Russian Federation. Hybridoma cells were incubated in the peritoneal cavity of BALB/c mice. Preparations of glanders and melioidosis monoclonal antibodies were isolated from the ascetic fluids through precipitation with ammonium sulfate and purification by means of ion-exchange chromatography. Specific components of the test-kits were subjected to freeze drying in corresponding protective media. Study of diagnostic properties of the developed test systems was performed using ELISA. Results and conclusions. We have obtained preparations of monoclonal antibodies in vivo, as well as isolated and purified immunoglobulins from ascetic fluids. We also selected the pairs of monoclonal antibodies for manufacturing specific components. Experimental series of immune-enzymatic monoclonal test-systems allowing for specific detection of glanders and melioidosis causative agents in concentrations ranging from 0.5·106 CFU/ml and higher were made. The absence of cross-reactivity with closely related saprophytes and heterologous microorganisms in concentrations of 1,0·108 CFU/ml was shown. Demonstrated was the possibility in principle to differentiate between Burkholderia malleiand Burkholderia pseudomallei using ELISA. Test systems are promising for follow up state registration as medical products for in vitro diagnostics.
Epidemic complications in the territory of Gorno-Altai high-mountain natural plague focus, associated with increase in numbers of carriers and vectors of the dangerous diseases, entailed strengthening of preventive element in the system of epidemiological surveillance. Objective of the study was to assess the efficiency of disinsection and deratization during anti-epidemic campaign. Materials and methods. Investigations were performed in 2014-2017 in the territory of Kosh-Agach district of the Republic of Altai, based on the archival and operational records from Altai Plague Control Station, Rospotrebnadzor Administration in the Republic of Altai, and our own data. “Interactive Map on Management of Health Promotion Measures in Gorno-Altai high-mountain natural plague focus” was used as an assessment tool. Results and conclusions. The most hard-hitting sections of preventive complex as regards plague are still disinsection and deratization. Application of advanced methods and means of control over numbers of carriers and vectors of the infection testify to their high anti-epidemic effectiveness. Insecticide and rodenticide treatments of encampments situated in epizootic areas, disinsection and deratization in major population centers in the territory of the focus allowed for the reduction in risk of population infection. Technical efficiency of the field disinsection amounted to 96.7 %, community deratization and disinsection varied from 91.6 to 100 %. Emergency insecticide and rodent treatments in epizootic areas alongside other measures provided for epidemiological welfare on plague.
Objective of the investigation was a comparative bioinformatics analysis of rtxA gene translation products of Vibrio cholerae strains isolated from patients and environmental objects. Materials and methods. 32 Vibrio cholerae strains from the Rostov-on-Don Research Anti-Plague Institute collection were used. DNA sequencing was conducted on the MiSeq platform (Illumina), gene identification and analysis was carried out by means of BioEdit 7.2.5, BLASTN 2.2.29, Blastp, Vector NTI Advance 11 software programs. Results and conclusions. The rtxA genes of the studied strains were represented by multiple alleles. AlignX-analysis of their deduced products divided 32 proteins into 3 separate clusters. The first one included proteins of O1 and nonO1/nonO139 strains similar to the prototype, the second – nonO1/nonO139 only, the third – O139. Blastp-analysis revealed that the proteins of the first cluster retained all domains characteristic of MARTX – ACD (actin cross-linking), RID (Rho GTFase inactivation), CPD (cysteine protease) and ABH (alpha-beta hydrolase) which evidences the probability of manifestation of the typical activity. In 3 strains a new Hia domain (of putative adaptation factor) was detected. The proteins of the second cluster lacked ACD but formed an additional RID; two of which lacked ABH too, but in one, VIP2 domain (of actin modification) appeared and in another – Hia. These data are in accordance with the presumption of J. Dolores, K.J.F. Satchell (2013) on the possible converting of actinomodulator MARTX into toxins with other mechanisms of action. The proteins of O139 vibrios shared all specific domains except from ACD. For a number of altered proteins revealed by us full homologues were found in NCBI gene bank, belonging to isolates from other regions of the world. The presence of similar determinants in the genomes of strains of different origin points to non-occasional character of their conservation. It is possible that certain strains “deliberately” alter those genes or switch off the synthesis of the high-molecular toxin completely with a view to energy-saving.
Objective of the study was to develop enzyme-immunoassay test-kit for the detection of Bacillus anthracis spores. Materials and methods. Microbial cultures from the State Collection of Microorganisms at the premises of Affiliated Branch of the «48th Central Research Institute» of the Ministry of Defense of the Russian Federation and BALB/c mice were used in the research. Hybridization of B-lymphocytes with SP2/0-Ag14 myeloma cells was performed according to G. Kohler and C. Milstein procedure in De St. Fazekas and P. Scheidegger modification. Hybridomas were cultured in the peritoneal cavity of BALB/c mice. Ascitic fluids were isolated from mice, precipitated with ammonium sulfate and purified by means of ion-exchange chromatography for preparation of monoclonal antibodies. Specific activity of hybridoma’s supernatants, ascitic fluids, purified monoclonal antibodies was studied by «sandwich» ELISA. Specific components of test-kit were lyophilized in suitable cryoprotective medium. Results and conclusions.We have obtained new hybrid cell lines producing specific monoclonal antibodies against Bacillus anthracisspore antigens and ascitic fluids from which immunoglobulins were isolated. Optimum combinations of monoclonal antibodies as a sensitizer and a component of immunoperoxidase conjugates have been selected. Monoclonal antibodies 272E10G1-272F7A10 provide the highest sensitivity of ELISA for the detection of anthrax microbe spore antigens. Our enzyme-immunoassay test allows for identification of Bacillus anthracis spores in concentrations up to 5,0·105 spores per milliliter. No cross reaction with closely related saprophytes and other heterologous microorganisms in concentrations of 1,0·108 CFU per milliliter is observed.
In 2017, from October 15 to November 21, 5 cholera cases imported from India – 3 patients and 2 carriers of V. cholerae – were recorded in Almaty. The patients recovered from the disease. Objective of the study was to characterize the imported cases of cholera and investigate the properties of cholera vibrio strains isolated from patients and carriers of V. cholerae. Materials and methods. Revised were the medical records; blood sera, feces from patients and contact persons were assayed. Studied were sensitivity spectrum to antibacterial preparations of isolated V. cholerae strains according to the “Methodological guidelines on laboratory diagnosis of cholera”, dated September 27, 2010; No 252. Epidemiological, microbiological, immunological and molecular-genetic methods were applied for investigation. Results and conclusions. Consequently to molecular genetic studies, genes of specificity, wbeN and toxicity (epidemic significance), ctxA, tcpA were detected in samples from 3 patients and 2 contact persons. The isolated strains were identified as Vibrio cholerae O1 Eltor Inaba in two cases, and in one case – as Vibrio cholerae O1 Eltor Hykoshima, Heiberg group I, toxigenic, hemolysis negative in Greig test, virulent, highly sensitive to ciprofloxacin, doxycilin, erythromycin, tetracycline and moderately sensitive to levomycetin. It was established that the country of export in all the cases was India. Relevant anti-epidemic and preventive measures were undertaken to localize and eradicate the foci in order to prevent possible threat of epidemic spread of infections among the population.
Objective of this work was to develop the algorithms for differential PCR indication of Brucella genus strains using databases of their genomes. Materials and methods .Resources of the National Center for Biotechnology Information (NCBI) and BLAST and Vector NTI 9.1.0 software utilities. For PCR amplification, B. suis, B. abortus, B. melitensis nucleic acids, as well as plasmid DNA with marker insertions were used. Results and conclusions. We assessed brucella gene sequences, some of which are found in Brucella genus bacteria, others only in representatives of B. melitensis, and the third ones – only in representatives of B. abortus. As a result of primers and probes designing for indication of Brucella genus bacteria and representatives of B. melitensis and B. abortus species, criteria for marker sequence amplification have been established. These criteria provide for simultaneous differentiation in a single reaction. The determination of strain differences within one species of Brucella is described in multilocus VNTR assay technique, and the profiles of tandem repeats of various B. melitensis and B. abortus strains are available in the public domain. To monitor the progress of amplification, a positive control has been developed that has the nucleotide sequence of all marker regions. The text of the paper discloses all the nucleotide sequences of primers, probes and positive control, which makes it possible to independently acquire them in competent organizations.
BRIEF COMMUNICATIONS
Objective of the study was to assess epidemiological and epizootiological activity of natural tularemia foci in the Republic of Tatarstan for further forecasting of the developments and working out the tactics for implementation of preventive and anti-epidemic measures. Materials and methods. We utilized statistical data, reports of the Center of Hygiene and Epidemiology in the Republic of Tatarstan, and literature sources for the analysis. Results and conclusions. Since 1995, the incidence among the population in Tatarstan has not been registered. Natural tularemia foci are situated in 19 enzootic as regards the infection administrative districts in the territory of the Republic. Epizootiological monitoring of the natural foci suggests that over the last four years their activation occurred. In this contest realization of complex anti-epidemic measures, regulated by the current normative-methodological documents remains relevant, as well as timely and effective diagnostics, including among the patients with a similar to tularemia symptoms.
ISSN 2658-719X (Online)