Plague Foci Research Articles

Апробация устройств для дезинсекции нор мелких млекопитающих в Горно-Алтайском высокогорном природном очаге чумы

Апробация устройств для дезинсекции нор мелких млекопитающих в Горно-Алтайском высокогорном природном очаге чумы

The Analysis of Factors Influencing Immunologic Reactivity in People Vaccinated with a Live Plague Vaccine

Introduction: An increase in epizootic activity has been registered in a number of plague foci in the Russian Federation over the past few years. As part of securing sanitary and epidemiologic wellbeing of the population living in the natural foci of the disease, a mass immunization with a live plague vaccine based of the Yersinia pestis EV line NIIEG vaccine strain was carried out. Objectives: The purpose of the study was to assess the influence of a complex of factors including age, gender, health status, the number of previous vaccinations against plague, blood groups, and HLA gene polymorphism on the state of the cellular and humoral immune response in people vaccinated with the live plague vaccine. Materials and methods: The analysis of venous blood of 347 volunteers included determination of the concentration of specific antibodies to the capsular antigen (F1) of plague microbe, spontaneous and induced production of marker cytokines (IFN-γ, TNF-α, and IL-4) by ELISA, and genes of the main histocompatibility complex (HLA) class II by real-time PCR. We also analyzed medical documentation (Form 025/u) and the results of a questionnaire-based survey of the vaccinated people. Results and discussion: We established the influence of various factors, including genetic ones, on marker indicators of the humoral and cellular immune response in persons vaccinated with the live plague vaccine. We also characterized the relationship between the level of specific antibodies to plague microbe F1 production and some cytokines and the age and the number of previous vaccinations in our volunteers. The most common gene variants of the main histocompatibility complex of class II (HLA-DQA1, HLA-DQB1 and HLA-DRB1) in the cohort were identified and possible relationships between the production of IFN-γ, TNF-α, IL-4 and allelic polymorphism of HLA class II genes were determined. Conclusions: Immunologic reactivity in people vaccinated with the live plague vaccine is mainly determined by age, the number of previous vaccinations against this infection, and individual characteristics of HLA gene polymorphism.

Phylogeny of Yersinia pestis Strains Belonging to 0.ANT Branch, Isolated in Tien-Shan and Pamir-Alay in XX–XXI Centuries

Objective of the study was to conduct phylogenetic analysis of Yersinia pestis strains of the main subspecies, belonging to antique biovar, phylogenetic branch 0.ANT, isolated in XX – early XXI centuries in the foci of Tien-Shan and Pamir-Alay to identify the regularities of spatial-temporal circulation of plague agent in the territory of the foci. Materials and methods. We have carried out whole genome SNP-analysis of Y. pestis strains of antique biovar, isolated in natural foci of Kyrgyz Republic in 1928–2016. Phylogenetic investigation is based on 1646 identified core SNPs in 51 included in the analysis strains of different phylogenetic lines. Phylogenetic tree was constructed using Maximum Likelihood algorithm, PHYML software package, and HKY85 model. Results and discussion. All 29 studied Y. pestis strains isolated between 1928 and 2016 in the foci of Tien-Shan and Pamir-Alay fall under the phylogenetic branches 0.ANT3 and 0.ANT5 of antique biovar of the main subspecies. Strains of 0.ANT3 branch were collected predominantly in Aksay and Alay foci, while strains of 0. ANT5 – in Upper-Naryn and Sarydzhas foci of Tien-Shan. Strains of phylogenetic lines 0.ANT1 and 0.ANT2 were not found in the foci of Kyrgyz Republic. According to the results of whole genome SNP-analysis, Y. pestis strains isolated in the XXI century belong to phylogenetic branch 0.ANT5. This branch also comprises a strain obtained from a patient (lethal case) in Sarydzhas plague focus in 2013. Genetic homogeneity of the modern strains of 0.ANT5 branch and their wide dissemination testify to the extension of the areal of this population and activation of Tien-Shan foci, caused by climate warming. For the first time ever, genomes of Y. pestis 0.ANT5 branch, isolated in XXI century, including clinical strain dated 2013, have been sequenced. We have obtained the whole-genome sequence of Y. pestis strain, 0.ANT3 branch, which caused pneumonic plague outbreak in Tien-Shan in 1928.

Epidemiological and Epizootic Situation on Plague in the Russian Federation and Forecast for Its Development for 2020–2025

Objective of the investigation was to assess epidemiological and epizootiological conditions in natural plague foci of the Russian Federation, neighboring states and foreign countries in 2019. Negative effect of the current climate warming on the state of parasitic systems of natural foci with circulation of plague microbe of the main subspecies, medieval biovar, phylogenetic branch 2.MED1 is emphasized. In 2019, local plague epizooties were registered in the territory of two (Gorno-Altai high-mountain and Tuva mountain) out of 11 natural plague foci of the Russian Federation. The total area of epizooty covered 2248.5 km2 . All in all, 31 cultures of Y. pestis of the main subspecies, antique biovar, phylogenetic branch 4.ANT and 5 cultures of Altai biovar, central-asian subspecies, phylogenetic branch 0.PE4a were isolated. The forecast for continuing tense epidemiological situation, both for 2020 and for 2021–2025, has been substantiated for natural foci with circulation of the main subspecies of antique biovar, phyologenetic branch 4.ANT: Gorno-Altai high-mountain and Tuva mountain ones. In the remaining nine natural foci in the territory of the Russian Federation epizootic manifestations of plague in 2020 are highly improbable. This prognosis is an indication to optimize the deployment of human and logistical resources of plague control institutions through concentrated preventive activities in the territories of epizootically active natural plague foci. Otlined is the necessity to put a new enhanced classification of Y. pestis into practice.

The characteristics and genome analysis of the novel Y. pestis phage JC221

The pathogen of plague is Yersinia pestis (Y. pestis), one of the deadliest pathogens in the world and belonging to the family Enterobacteriaceae. In this work, the biological characteristics and complete genome sequence analysis of a novel lytic Y. pestis-specific phage JC221 isolated from Yunnan Province, China, was studied. JC221 belongs to the Myoviridae family and has a regular icosahedral head and a long contractile tail. The double-stranded DNA genome of JC221 contains 174,931 bp, and the G + C content is 41.23 %. There are 274 predicted genes, of which only 103 hits of genes or gene products are found in database searches, and there are no known virulence-related or antibiotic resistance genes. The genome sequence of JC221 showed <80 % identity to other phages, and evolutionary analysis revealed that bacteriophage JC221 belongs to the Yersinia phage cluster. Furthermore, the bacteriophage could completely lyse most of the tested Y. pestis strains (12/13) at 28 °C and 37 °C, and some Shigella strains could be lysed at 37°C. Morphological and genomic analysis indicated that JC221 is a new Y. pestis phage and a new member of the Tequatrovirus phages. The novel Y. pestis phage JC221 has important reference value for the study of environmental microecology and epidemiology of plague foci.

Soil salinity and aridity specify plague foci in the United States of America

Plague is a deadly zoonosis that periodically reemerges as small outbreaks in geographically limited foci where the causative agent Yersinia pestis may reside in soil. We analyzed a dataset of 1.005 carefully documented plague cases that were georeferenced over 113 years in peer-reviewed literature in the contiguous United States. Plotting outbreaks by counties defined as plague foci on geographical maps, we observed a significant co-localization of plague outbreaks with high soil salinity measured by an electric conductivity of >4 dS/ m−1 and aridity measured by an aridity index <0.5. Thus, we identified aridity and soil salinity as significantly associated with ecological risk factors for relapsing plague in the contiguous United States. These results reveal two evolutive parameters that are partially associated with anthropic activities, complicating the epidemiology of plague in the contiguous United States. Exploiting aridity and soil salinity data may help in the surveillance of evolving plague foci in the contiguous United States.

The Significance of Fleas (Siphonaptera) in the Natural Plague Foci

The role of fleas in the manifestations of plague epizootics in the natural plague foci in Russia and adjacent states is discussed. The specific conditions of pathogen transmission in each focus are determined by the vital activities of several species of fleas that are parasites of the main plague carrier. These fleas have the nidicolous type of parasitism, facilitating wide spread of the plague microbe in the focus. Most of the natural plague foci include more than one vector species. The most intense epizootic outbreaks in each focus occur during the periods of active feeding and reproduction of the flea vectors.

Wild Rodents and Their Ectoparasites in an Enzootic Plague Focus, Western Iran.

Introduction: Entomological surveys of ectoparasites and their hosts are an essential tool for assessing the risks of rodent-borne diseases transmitted to humans by arthropod vectors. Objectives: This study was carried out to update the epidemiological data of plague with respect to species compositions of the rodents and their ectoparasites at enzootic foci located in Kurdistan Province, Iran. Methods: The rodents' habitats were selected based on past records of plague and subclimates in each study district with especial attention to the vegetation type. The trapped rodents were anesthetized using a chloroform chamber, and the animals were then examined for ectoparasites by brushing their hair over a pan containing water. The ectoparasites were collected with a fine brush and preserved in 70% ethanol in screw cap tubes. Results: A total of 208 rodents were trapped from three districts. Taxonomic ranking of the rodents indicated that the specimens belonged to 2 suborders of Myomorpha and Sciuromorpha, 4 families (Muridae, Muscardinidae, Cricetidae, and Sciuridae), 7 genera, including Meriones, Apodemus, Mus, Sciurus, Microtus, and Dryomys, and 15 species. Out of 208 rodents, only 56 (26.9%) were infested with 22 species of ectoparasites. Totally, 312 ectoparasites were isolated from 56 rodents, including 12 flea species (54.5%), 6 mite species (27.3%), 3 tick species (13.6%), and one louse species (4.6%). Five species of fleas were recorded for the first time in Kurdistan Province, including Ctenophthalmus iranus persicus, Paraceras melis melis, Nosopsyllus iranus iranus, Paraceras sp., and Ctenophyllus spp. Conclusion: The finding revealed new records for rodents and ectoparasites in Kurdistan Province, as well as changes in dominant rodent species and their ectoparasites compared to previous studies. This phenomenon can influence the changes in the incidence of plague and its epidemiology.

Population Approach to Determination of the Borders and Number of Natural Plague Foci

Population approach to determination of the borders and number of natural plague foci implies the specialists’ acceptance of the concept that the existence of a natural plague focus is always provided by a single population of the main carrier. Motivation for our discussion of such an approach was the data of a long-term study of the Hissar natural plague focus (Tadzhikistan). The area of the focus was only 300 km2 and its functioning was maintained by a single, relatively small population of Microtus carruthersi (Thomas, 1909) – the main carrier of plague. The Hissar mountain range territories adjacent to the focus have been surveyed for plague for more than 20 years, however, no plague agent (Yersinia pestis Lehmann, Neuman 1986) has been found, despite the complete identity of the species composition of rodents and fleas. Many of the known natural plague foci are significantly larger in size than the Hissar focus and inhabited by several populations of the main carrier. For instance, in the East-Caucasian high-mountain focus, covering the area of 23,500 km2 , five groups of common vole populations (the main carrier of plague) are distinguished (Microtus arvalis Pallas, 1778). In the Tuva mountain focus, the plague agent was detected in six populations of the main carrier – the long-tailed souslik (Spermophilus undulates Pallas, 1778). In the territory of the Mojynkumsky desert natural plague focus that occupies 93,000 km2 , 17 populations of the great gerbil (Rhombomus opimus Lichtenstein, 1823) were singled out. Similar data are available for a number of other foci. Revealingly, in different populations of the main carriers, genotype differences were identified, both in rodents and the plague agent, as well as asynchrony in the plague epizooty development. Thus, the plague parasitic coenosis, operating within the boundaries and in the territory of a single population of the main carrier, constitutes an autonomous, standalone natural focus. Therefore, the foci with several populations of the main carrier are, in fact, groups of autonomous foci with a close, similar biocoenotic structure. There are many more natural (autonomous) foci within the natural plague focality zone than is widely assumed.

Dissemination of &lt;i&gt;Yersinia pestis&lt;/i&gt; of Medieval Biovar in Northern, North-Western Caspian Sea Region and Fore-Caucasus in the second Half of the Twentieth Century

Objective of the study was to determine the origin of Y. pestis strains that widely disseminated in natural plague foci of Northern, North-Western Caspian Sea region and Fore-Caucasus in the second half of the XX century. Materials and methods . We have carried out the investigation of properties and whole genome sequencing of 22 Y. pestis strains, isolated between 1923 and 2003 in five natural foci of the souslik type, situated in Northern and North-Western Caspian Sea region and Fore-Caucasus. Phylogenetic analysis was conducted using the data of whole genome SNP-typing, based on 1348 identified SNPs. The search of SNPs in the core genome was performed with the help of Wombac 2.0 software. Phylogenetic relations were analyzed using Maximum Likelihood dendrogram, GTR model. Results and discussion . All the studied strains from the foci of Northern, North-Western Caspian Sea region and Fore-Caucasus fall into phylogenetic branch 2. MED1of medieval biovar. On the basis of whole genome SNP-analysis, existence of two groups of closely related strains, comprising the strains dated 1923-1945 and 1962-2003, has been revealed. The predecessors of the 1962-2003 strains from the Northern, North-Western Caspian Sea region and Fore-Caucasus on the phylogenetic tree are the strains from Northern Aral Sea region that go back to 1945. It testifies to the fact that synchronized activation of a group of natural foci in Caspian Sea lowland and Fore-Caucasus in 1975-1979, after prolonged 20-37 year long breaks, could be caused by the dissemination of the strains from the Northern Aral Sea region. The data of epizootic observations indicate that activation of Volga-Ural sandy plague focus in 1960s preceded the start of registration of plague epizooties in the territory of natural foci of souslik type in Northern, North-Western Caspian sea region and Fore-Caucasus.

Construction of &lt;i&gt;Yersinia pestis&lt;/i&gt; Strain Producing Fluorescent Protein GFP and Prospects of Its Usage

Objective of the study was to construct the recombinant Y. pestis strain producing fluorescent protein GFP and analysis of the prospects of its usage for investigation of interaction of the agent with the protozoa, and also macroorganism of mammals (rodents). Materials and methods . To create the strain producing fluorescent protein GFP, we used the natural Y. pestis strain isolated in 2016 in Gorno-Altai high-mountain plague focus. Fluorescent protein gen was inserted into commercial vector pTurboGFP-B via electroporation. Properties of the obtained recombinant Y. pestis strain 367 pTurboGFP-B were studied using microbiological, biological, and molecular-genetic methods. Results and conclusions . The plague agent strain, containing vector plasmid pTurboGFP-B which encodes synthesis of green fluorescent protein GFP, and being resistant to ampicillin was constructed applying electroporation. The designed Y. pestis strain, producing green fluorescent protein, does not differ from the stock strain by its cultural-morphological, biochemical properties, virulence and survivability in mixed culture with Acanthamoeba castellani . On solid nutrient media, recombinant strain and its subcultures, obtained from infected animals, formed colonies of greenish-yellow color, becoming fluorescent under UV-light. In preparations from animals and from co-cultures with amoeba, fluorescent cells of plague agent were observed. The constructed strain can be utilized as a model one for investigation of interactions between plague agent and cells of protozoa (soil amoeba, nematodes) and mammals under laboratory conditions.

Evolutionary selection of biofilm-mediated extended phenotypes in Yersinia pestis in response to a fluctuating environment

Yersinia pestis is transmitted from fleas to rodents when the bacterium develops an extensive biofilm in the foregut of a flea, starving it into a feeding frenzy, or, alternatively, during a brief period directly after feeding on a bacteremic host. These two transmission modes are in a trade-off regulated by the amount of biofilm produced by the bacterium. Here by investigating 446 global isolated Y. pestis genomes, including 78 newly sequenced isolates sampled over 40 years from a plague focus in China, we provide evidence for strong selection pressures on the RNA polymerase ω-subunit encoding gene rpoZ. We demonstrate that rpoZ variants have an increased rate of biofilm production in vitro, and that they evolve in the ecosystem during colder and drier periods. Our results support the notion that the bacterium is constantly adapting—through extended phenotype changes in the fleas—in response to climate-driven changes in the niche.

INFLUENCE OF POLYOXIDONIUM, Poly(I:C), DALARGIN ON THE PROTECTIVE EFFICACY OF YERSINIA PESTIS VACCINE STRAIN EV LINE NIIEG IN EXPERIMENTAL PLAGUE

In this study, the use of immunoadjuvants polyoxidonium (azoximer bromide), Poly (I:C) as a synthetic analog of double-stranded RNA (TLR3 ligand), and synthetic analog of leu-enkephalin dalargin (DA) was experimentally investigated for their potential to minimize ImD50 Yersinia pestis vaccine strain EV line NIIEG co-administrated via invasive (subcutaneous) and noninvasive (intranasal) routes in lethal bubonic and pneumonic models of plague followed by challenge with virulent Y. pestis strains of the main and non-main subspecies from various natural plague foci. The data showed that in all cases immunoadjuvants significantly increased protective efficacy of Y. pestis vaccine strain EV line NIIEG co-administrated to BALB/c inbreed mice in case of lethal challenge with virulent Y. pestis strains in spite of varying magnitude of humoral immune response. Y. pestis vaccine strain EV line NIIEG formulated with polyoxidonium provided more effective protection against lethal challenge with wild-type high virulent strain Y. pestis in pneumonic model of plague. Polyoxidonium introduced into vaccine formula resulted in four-fold rise in total survival in animals with pneumonic plaque. Feasibility of using immunoadjuvants for regimen of specific and urgent plaque prevention is justified.

Molecular detection of Rickettsia spp., Borrelia spp., Bartonella spp. and Yersinia pestis in ectoparasites of endemic and domestic animals in southwest Madagascar

Little is known about the presence of vector-borne bacteria in southwest Madagascar. Anthropogenic alteration of natural habitats represents an important driver for the emergence of new diseases. Especially the involvement of livestock and the involuntary maintaining of invasive synanthropic animals (particularly rats) facilitate disease transmission from wildlife to humans and associated animals and vice versa. The dissemination or acquisition of ectoparasites is most likely in regions where human/wildlife contact is increasing. Little is known about the presence of vector-borne bacteria in southwest Madagascar. In 2016 and 2017, ectoparasites were collected from various introduced (cattle and goats, cats, dogs and chicken, rats and mice) and native animal species (mouse lemurs [Microcebus griseorufus], Grandidier's mongooses [Galidictis grandidieri], bastard big-footed mice [Macrotarsomys bastardi], greater hedgehog tenrecs [Setifer setosus] and lesser hedgehog tenrecs [Echinops telfairi]) in the northern portion of Tsimanampetsotsa National Park and the adjacent littoral region. Thirteen species of blood-feeding ectoparasites (235 individuals of ticks [5 species], 414 lice [4 spp.] and 389 fleas [4 spp.]) were investigated for the presence and identity of rickettsiae, borreliae, bartonellae and Yersinia pestis using PCR techniques. Rickettsia spp. were detected in every single ectoparasite species (Amblyomma variegatum, A. chabaudi, Rhipicephalus microplus, Haemaphysalis simplex, Argas echinops, Ctenocephalides felis, Echidnophaga gallinacea, Pulex irritans, Xenopsylla cheopis, Haematopinus quadripertusus, Linognathus africanus, L. vituli, Lemurpediculus verruculosus). Lice and ticks were found harboring rickettsiae identified as Rickettsia africae, while Rickettsia felis-like bacteria were associated with fleas. Borrelia spp. were detected in 5% of H. simplex and 1% of R. microplus ticks. Bartonella spp. were detected in 40% of H. quadripertusus pools and in 5% of L. verruculosus pools. Y. pestis was detected in X. cheopis and E. gallinacea fleas collected from a rat. This study presents the detection of a broad spectrum of vector-borne bacteria including potential pathogens, and an unexpected finding of Y. pestis far off the known plague foci in Madagascar.

Биологические свойства и молекулярно- генетическая характеристика штаммов чумного микроба, циркулирующих в песчаночьих природных очагах чумы Республики Казахстан

Since 2010, an active course of epizootics with the release of the plague pathogen, isolated from hosts and vectors has been established in 8 autonomous foci of the plague from 14 autonomous foci of the Central Asian plague focus in Kazakhstan. It was necessary to take into account the parameters of variability of the main component of the parasitic system – the plague microbe in the process of certification of landscape and epizootological zoning of natural foci of plague in Kazakhstan. The aim of the work was to study the phenotypic and genetic properties of strains of the plague microbe isolated in natural sandy plague foci of Kazakhstan. Materials and methods. The work used 1196 strains of Yersinia pestis isolated over the past 10 years (2010–2019) from natural sandy plague foci, strain passports, literature sources, data on certification of plague foci in Kazakhstan. The study of the strains was carried out by bacteriological, serological and molecular genetic methods. Results. Certification and typification of the territories of sandy plague foci were carried out, taking into account the phenotypic and molecular-genetic properties of Y. pestis strains isolated from 12 autonomous foci of the Central Asian plague focus of Kazakhstan in 2010–2019. According to the results of the study, 84 atypical strains were identified. As a result of the analysis, 18 genotypes were identified among the studied strains, of which 13 (72.2%) were unique and did not repeat in the sample. The remaining 5 genotypes formed 5 clusters, combining 20 strains (60.6%) and all strains were phylogenetically assigned to representatives of the Mediaevalis biovar. Key words: plague microbe, plague foci, phenotypic features, molecular genetic features

Diversity of Fleas, Vectors of Plague Pathogens: the Flea Oropsylla silantiewi (Wagner, 1898) (Siphonaptera, Ceratophyllidae)

The taxonomic diversity, distribution patterns, and host-parasite relationships of fleas of the genus Oropsylla, which are vectors of the plague pathogen in the Eurasian and North American plague foci, are analyzed. Data on the abundance, ecological features, and epizootological significance of the marmot parasite Oropsylla silantiewi (Wagner, 1898) in different Palaearctic plague foci are summarized.

Конструирование системы мультиплексных ПЦР с гибридизационно-флуоресцентным учетом результатов на твердой подложке для индикации и идентификации штаммов возбудителя чумы

Plague agent strains differ in intraspecific appurtenance, place of origin, as well as their virulence. Development of a rapid and reliable means of Y. pestis strain indication, their identification by intra-specific appurtenance and assessment of their virulence is a relevant issue. To solve the task, we have constructed a system of multiplex PCR with hybridization-fluorescent registration of results on solid substrate, for indication and identification of strains by their belonging to Y. pestis species, sub-species, biovars, phylogenetic lines, also by the presence of the main gene-factors of pathogenicity of chromosomal and plasmid localization. Its effectiveness is confirmed on 114 plague agent strains of various origins. The developed system of multiplex PCR with hybridization-fluorescent registration of results on solid substrate, can be applied for molecular-genetic identification of strains from natural plague foci with specification of their appurtenance to the main phylogenetic branches and assessment of virulence, for enhancement of sanitary-epidemiological control of RF territories and CIS member-states. plague pathogen, strains, indication and identification, PCR

Мониторинг хлорорганических пестицидов в грудном молоке женщин Кыргызстана

Статья посвящена актуальной проблеме химической безопасности, до сих пор не исследованной должным образом - последствиям широкого применения пестицидов в исторический период 1970-80-х гг. на территории республик бывшего СССР, что до сих пор оказывает негативное влияние на экологическую ситуацию. Приведены результаты выполненных анализов на наличие стойких органических загрязнителей - хлорорганических пестицидов (ХОП) в грудном молоке 108 женщин, проживающих в сельской местности на юге Кыргызстана в разных экологических зонах. В пробах грудного молока 37 из 108 обследованных женщин обнаружены четыре вида ХОП: дихлородифенилэтилен (ДДЭ) и три изомера гексахлорциклогексана - альфа-ГХЦГ, бета-ГХЦГ и гамма-ГХЦГ. Доля лиц с ХОП в грудном молоке составляла от 0 до 100 процентов в различных группах, максимальная обнаруженная суммарная концентрация ХОП достигала 0,29 мг/л. Результаты рассмотрены в связи с данными о наличии источников загрязнения в местах бывшего применения пестицидов. Источником загрязнения ХОП в условиях юга Кыргызстана могут быть территории, расположенные на высоте свыше 3500 м над уровнем моря, которые в прошлом были очагами чумы и где в 1980-е годы были проведены дустации норок возбудителей инфекции сурков с использованием ДДТ (дихлородифенилтрихлорэтан). Кроме того, вторичными источниками загрязнения ХОП являются бывшие агроаэроплощадки и склады ядохимикатов, находившиеся в активном использовании более 30 лет назад. Полученные и литературные данные проанализированы с целью разработки мероприятий, направленных на реабилитацию окружающей среды и защиту здоровья населения. The current study highlights a challenging issue of chemical safety, which has not yet been adequately studied, i.e. far-reaching after-effects of widespread use of pesticides in the historical period of the 1970-80s on the territory of the former USSR republics, which still has an adverse impact on the environment. Results of analyzes for the presence of persistent organic pollutants - organochlorine pesticides (OCPs) in breast milk of 108 women living in rural areas of southern Kyrgyzstan in different ecological zones are presented. Four types of OCPs have been found in the breast milk samples obtained from 37 of 108 women, i.e. dichlorodiphenylethylene (DDE) and three isomers of hexachlorocyclohexane - alpha-HCH, beta-HCH, and gamma-HCH. The proportion of women with OCPs detected in the breast milk varied in the range from 0 to 100 percent with the maximum total pesticide concentration reaching 0.29 mg/L. The results are discussed in terms of data available for sources of pollution at the sites of the former pesticide use. Possible sources of OCP pollution in southern Kyrgyzstan can be associated with territories located at an altitude of more than 3,500 m above sea level, which have been former foci of plague and where marmot holes have been treated with DDT (dichlorodiphenyltrichloroethane) as an infection pathogen-fighting agent, in the 1980s. Additionally, the secondary sources of OCP pollution can be attributed to the former pesticides storehouses, agro-air strips, etc., which have been intensively used more than 30 years ago. The obtained and published literature data are analyzed for the purpose of developing measures aimed at rehabilitation of the environment and human health protection.

Efficiency of Human Plague Vaccination in Tuvinian Natural Plague Focus

Background. Plague is an especially dangerous natural focal infectious disease belonging to a group of quarantine infections. There are eleven natural plague foci in Russian Federation. In Republic Tyva plague endemic territories include Ovyur, Mongun-Taigin and Tes-Hem areas where Y. pestis strains are intermittently isolated from Citellus undulates. Population living at the territory of the natural foci get immunoprophylaxis against plague at complication of epizootic and epidemic conditions.This paper presents the results of monitoring indicators of the immune status of people vaccinated with the plague vaccine living in the territory of the Tuva natural focus.Materials and methods. The study involved 76 volunteers who had not previously been vaccinated. The study included the determination of production IFN-γ, IL-4, TNF-α by blood cells, titers of specific IgG antibodies to the capsule F1 antigen of the Yersinia pestis, and concentrations of immunoglobulins in serum blood, as well as immunophenotyping of blood lymphocytes.Results. In the course of a comprehensive immunological study, features of the development of cellular and humoral reactions in people living in the territory of the Tuva natural plague focus were established in the first months after vaccination. Changes in the concentration dynamics of the main classes of immunoglobulins were accompanied by an increase in the level of specific IgGs to the F1 within 6 months after immunization. In the same period, a significant increase in the production of cytokines, as well as significant changes in terms of the subpopulation composition of the vaccinated blood.Conclusion. It is necessary to note the importance of studying of the human immune status in 1–3 months after plague vaccination as this period coincides with potentially dangerous season from epidemiological point of view. Nevertheless, much important role for improvement of tactics of the specific prevention measures plays the data received after the revaccination.

Вклад трудов профессора Н.Н. Клодницкого (1868–1939) в становление учения о природной очаговости чумы

Вклад трудов профессора Н.Н. Клодницкого (1868–1939) в становление учения о природной очаговости чумы